|
DAVE,
Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI] http://www.radiointel.com/review-ats505.htm Two points made by the reviewer we * "An external antenna jack is provided, but it only works for SW (not AM/MW)." * "This receiver is quite sensitive on SW and I found that using an external antenna overloaded it." iane ~ RHF .. .. = = = "Dave" wrote in message = = = ... - - - - - S N I P - - - - - Sorry, forgot to include that information. I am using a DX-402 (aka Sangean ATS-505). I honestly wondered about that, but hesitated to shorten the wire because I would (obvioiusly) lose some sensitivity, and really like being able to pick up VOK's English broadcasts to Central America. Only problem is the noise that makes it difficult to single out. Thanks, Dave |
Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash surrounding them (like Voice of Korea's broadcast to Central and South America.) I am planning on building a preselector anyway, and will post updates on the effects of that addition. Dave "RHF" wrote in message om... DAVE, Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI] http://www.radiointel.com/review-ats505.htm Two points made by the reviewer we * "An external antenna jack is provided, but it only works for SW (not AM/MW)." * "This receiver is quite sensitive on SW and I found that using an external antenna overloaded it." iane ~ RHF . . = = = "Dave" wrote in message = = = ... - - - - - S N I P - - - - - Sorry, forgot to include that information. I am using a DX-402 (aka Sangean ATS-505). I honestly wondered about that, but hesitated to shorten the wire because I would (obvioiusly) lose some sensitivity, and really like being able to pick up VOK's English broadcasts to Central America. Only problem is the noise that makes it difficult to single out. Thanks, Dave |
Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash surrounding them (like Voice of Korea's broadcast to Central and South America.) I am planning on building a preselector anyway, and will post updates on the effects of that addition. Dave "RHF" wrote in message om... DAVE, Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI] http://www.radiointel.com/review-ats505.htm Two points made by the reviewer we * "An external antenna jack is provided, but it only works for SW (not AM/MW)." * "This receiver is quite sensitive on SW and I found that using an external antenna overloaded it." iane ~ RHF . . = = = "Dave" wrote in message = = = ... - - - - - S N I P - - - - - Sorry, forgot to include that information. I am using a DX-402 (aka Sangean ATS-505). I honestly wondered about that, but hesitated to shorten the wire because I would (obvioiusly) lose some sensitivity, and really like being able to pick up VOK's English broadcasts to Central America. Only problem is the noise that makes it difficult to single out. Thanks, Dave |
Hmmm. Others have suggested I was overloading it, but I don't *think* that
is the case. It's just hard to dig weak signals out of the hash and trash surrounding them (like Voice of Korea's broadcast to Central and South America.) I am planning on building a preselector anyway, and will post updates on the effects of that addition. Dave "RHF" wrote in message om... DAVE, Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI] http://www.radiointel.com/review-ats505.htm Two points made by the reviewer we * "An external antenna jack is provided, but it only works for SW (not AM/MW)." * "This receiver is quite sensitive on SW and I found that using an external antenna overloaded it." iane ~ RHF . . = = = "Dave" wrote in message = = = ... - - - - - S N I P - - - - - Sorry, forgot to include that information. I am using a DX-402 (aka Sangean ATS-505). I honestly wondered about that, but hesitated to shorten the wire because I would (obvioiusly) lose some sensitivity, and really like being able to pick up VOK's English broadcasts to Central America. Only problem is the noise that makes it difficult to single out. Thanks, Dave |
DAVE,
So you have a Sangean ATS -505 and your 'problems' are Antenna Overload and Noise Levels. * Consider a 'smaller' shorter Antenna will reduce the overload problems. * Consider a Low Noise Antenna Design will reduce the noise problems. {LOW NOISE SWL ANTENNA - popularized by John Doty} http://groups.yahoo.com/group/Shortw...enna/message/2 http://www.anarc.org/naswa/badx/ante...e_antenna.html For a simple 'external' Shortwave Antenna to use with the Sangean ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack External Shortwave Antenna Input. Consider a Random Wire Antenna using a Matching Transformer and Ground for Low Noise and Wide Range Frequency Coverage. PARTS: Here is a simple SWL Antenna Idea using a few common RadioShack TV Antenna type parts: Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.) Catalog #: 274-286 = 1/8" Mono (Phone) Plug Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors NOTE: This is an 'improved' Random Wire SWL Antenna using "TV" Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in or near most modern homes/buildings. EXTERNAL "OUTSIDE" SWL ANTENNA: The Antenna [Loop] Element is Stretched outside Horizontally or in the shape of an Inverted "L". The Antenna [Loop] Element is formed by connecting the two ends of the Far-End of the 300 Ohm TV Twin Lead. This forms a continuous single skinny horizontal flat loop going out and back. This also represents a Balance 300 Ohm Load to match-up with the 300 Ohm Matching Transformer. The 300 Ohm Leads of the Matching Transformer connects to the Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector of the Matching Transformer is connected to the 75 Ohm Coax Cable. The 75 Ohm Coax Cable acts as the Lead-In from the Outside to inside the house to the radio shack. The other end of the 75 Ohm Coax Cable is connected to the 75 Ohm F Connector of the Matching Transformer. The Radio-End of the Coax Cable F Connector would connect to a 75 to 300 Ohm Matching Transformer; and then into a 1/8" Mono-Plug to plug into the Radio. NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop Antenna should balance-cancel-reduce most man made noise and be Omni-Directional. GROUND: Find a Grounding Point within/about your dwelling. Secure a good Grounding Point for your Radio and Antenna. Run a Heavy & Short Ground Wire to your Radio. Locate the Ground Terminal on your Radio. Attach/Secure the Ground Wire to the Coax Cable and/or the Radio's Ground Terminal. FWIW: This Antenna using common TV Antenna type parts should be effective as SWL Antennas above 5MHz and beyond 30MHz. iane ~ RHF .. Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond - The Beyond ! .. .. = = = "Dave" wrote in message = = = ... I recently hooked up a thirty-six foot (plus or minus a couple of feet) piece of four-stranded wire with alligator clip to the internal "whip" antenna of my portable shortwave receiver, for the extra performance such a device offered. It works so well that I now cannot usually use my "DX" setting because of all the background noise (sounds like hundreds of other broadcasts vying for attention.) I don't know the frequency source of all this background noise, but would like to filter out as much of it as I can. One manufacturer of a similar "wind-up" antenna adds a capacitor to the wire in order to lower the resonance frequency of the wire. If I were going to try something similar (adding a capacitor, in series) in an attempt to bring the resonance of the wire down into the 30 MHz range, what size (roughly) capacitor should I use? Should I just try a few with different ranges, or does anyone here have any suggestions? TIA Cross-posted between sci.electronics.basics and rec.radio.shortwave Dave .. |
Wow. Thank you for these concise and clear directions. One thing though, I
really don't *think* I am overloading the set. Only problem I have is digging the weak (but desired) signals our of the background noise surrounding them. In another post I mentioned Voice of Korea's Central and South American broadcast as the point of interest. It is just at the same level as the background noise that doesn't interfere with other broadcasts like the BBC on 5975 kHz or Radio Havana, Cuba on 9820 kHz (or Radio China International, originally from Taiwan and rebroadcast through some place in Florida, which frequency I can't remember at the moment.) It is only the weak signals I am having trouble with. If I tune into WWV our of Ft. Collins CO I can barely make out some out-of-band signals coming in, but they are so weak as to be vanishing. Does this still sound like overloading? Because the troublesom signals are also very weak, I am thinking that a preselector will probably take care of my problems. (I am still tempted to abandon my random wire and install your suggested antenna just because it sounds so much more sophisticated. Will let you know.) Thanks for the feedback. Dave "RHF" wrote in message om... DAVE, So you have a Sangean ATS -505 and your 'problems' are Antenna Overload and Noise Levels. * Consider a 'smaller' shorter Antenna will reduce the overload problems. * Consider a Low Noise Antenna Design will reduce the noise problems. {LOW NOISE SWL ANTENNA - popularized by John Doty} http://groups.yahoo.com/group/Shortw...enna/message/2 http://www.anarc.org/naswa/badx/ante...e_antenna.html For a simple 'external' Shortwave Antenna to use with the Sangean ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack External Shortwave Antenna Input. Consider a Random Wire Antenna using a Matching Transformer and Ground for Low Noise and Wide Range Frequency Coverage. PARTS: Here is a simple SWL Antenna Idea using a few common RadioShack TV Antenna type parts: Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.) Catalog #: 274-286 = 1/8" Mono (Phone) Plug Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors NOTE: This is an 'improved' Random Wire SWL Antenna using "TV" Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in or near most modern homes/buildings. EXTERNAL "OUTSIDE" SWL ANTENNA: The Antenna [Loop] Element is Stretched outside Horizontally or in the shape of an Inverted "L". The Antenna [Loop] Element is formed by connecting the two ends of the Far-End of the 300 Ohm TV Twin Lead. This forms a continuous single skinny horizontal flat loop going out and back. This also represents a Balance 300 Ohm Load to match-up with the 300 Ohm Matching Transformer. The 300 Ohm Leads of the Matching Transformer connects to the Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector of the Matching Transformer is connected to the 75 Ohm Coax Cable. The 75 Ohm Coax Cable acts as the Lead-In from the Outside to inside the house to the radio shack. The other end of the 75 Ohm Coax Cable is connected to the 75 Ohm F Connector of the Matching Transformer. The Radio-End of the Coax Cable F Connector would connect to a 75 to 300 Ohm Matching Transformer; and then into a 1/8" Mono-Plug to plug into the Radio. NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop Antenna should balance-cancel-reduce most man made noise and be Omni-Directional. GROUND: Find a Grounding Point within/about your dwelling. Secure a good Grounding Point for your Radio and Antenna. Run a Heavy & Short Ground Wire to your Radio. Locate the Ground Terminal on your Radio. Attach/Secure the Ground Wire to the Coax Cable and/or the Radio's Ground Terminal. FWIW: This Antenna using common TV Antenna type parts should be effective as SWL Antennas above 5MHz and beyond 30MHz. iane ~ RHF . Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond - The Beyond ! . . = = = "Dave" wrote in message = = = ... I recently hooked up a thirty-six foot (plus or minus a couple of feet) piece of four-stranded wire with alligator clip to the internal "whip" antenna of my portable shortwave receiver, for the extra performance such a device offered. It works so well that I now cannot usually use my "DX" setting because of all the background noise (sounds like hundreds of other broadcasts vying for attention.) I don't know the frequency source of all this background noise, but would like to filter out as much of it as I can. One manufacturer of a similar "wind-up" antenna adds a capacitor to the wire in order to lower the resonance frequency of the wire. If I were going to try something similar (adding a capacitor, in series) in an attempt to bring the resonance of the wire down into the 30 MHz range, what size (roughly) capacitor should I use? Should I just try a few with different ranges, or does anyone here have any suggestions? TIA Cross-posted between sci.electronics.basics and rec.radio.shortwave Dave . |
Sorry, all, for the repeated posts. It's not me, my ISP has been doing
something funny, and disconnecting me without warning. Every time I reconnect to do something else it reposts whatever is left in the job it never finished. Think it may be fixed now though. Dave "Dave" wrote in message ... Hmmm. Others have suggested I was overloading it, but I don't *think* that is the case. It's just hard to dig weak signals out of the hash and trash surrounding them (like Voice of Korea's broadcast to Central and South America.) I am planning on building a preselector anyway, and will post updates on the effects of that addition. Dave "RHF" wrote in message om... DAVE, Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI] http://www.radiointel.com/review-ats505.htm Two points made by the reviewer we * "An external antenna jack is provided, but it only works for SW (not AM/MW)." * "This receiver is quite sensitive on SW and I found that using an external antenna overloaded it." iane ~ RHF . . = = = "Dave" wrote in message = = = ... - - - - - S N I P - - - - - Sorry, forgot to include that information. I am using a DX-402 (aka Sangean ATS-505). I honestly wondered about that, but hesitated to shorten the wire because I would (obvioiusly) lose some sensitivity, and really like being able to pick up VOK's English broadcasts to Central America. Only problem is the noise that makes it difficult to single out. Thanks, Dave |
Dave wrote:
Wow. Thank you for these concise and clear directions. One thing though, I really don't *think* I am overloading the set. Only problem I have is digging the weak (but desired) signals our of the background noise surrounding them. In another post I mentioned Voice of Korea's Central and South American broadcast as the point of interest. It is just at the same level as the background noise that doesn't interfere with other broadcasts like the BBC on 5975 kHz or Radio Havana, Cuba on 9820 kHz (or Radio China International, originally from Taiwan and rebroadcast through some place in Florida, which frequency I can't remember at the moment.) It is only the weak signals I am having trouble with. If I tune into WWV our of Ft. Collins CO I can barely make out some out-of-band signals coming in, but they are so weak as to be vanishing. Does this still sound like overloading? Because the troublesom signals are also very weak, I am thinking that a preselector will probably take care of my problems. (I am still tempted to abandon my random wire and install your suggested antenna just because it sounds so much more sophisticated. Will let you know.) Thanks for the feedback. Dave If you don't hear that background noise with the whip antenna, the problem is almost certainly too much signal (overloading) from the external antenna. That's why I recommended a passive preselector. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"Dave" ) writes:
Hmmm. Others have suggested I was overloading it, but I don't *think* that is the case. It's just hard to dig weak signals out of the hash and trash surrounding them (like Voice of Korea's broadcast to Central and South America.) I am planning on building a preselector anyway, and will post updates on the effects of that addition. Dave But if it's really just adjacent signals, and I doubt it, nothing done at the antenna will fix the problem, unless you go to a directional antenna so you can null out the unwanted signals. You can't get enough selectivity at shortwave frequencies with coil and capacitor filters to knock out stations adjacent in frequency to what you want to hear. Well, a crystal filter at the signal frequency would work, but that gets complicated, and it's only good for one frequency. That's the whole point of the superhet receiver, to convert to a fixed frequency where a good filter can be built. Michael "RHF" wrote in message om... DAVE, Here is the RadioIntel 'review' of the Sangean ATS-505 by Russ [K3PI] http://www.radiointel.com/review-ats505.htm Two points made by the reviewer we * "An external antenna jack is provided, but it only works for SW (not AM/MW)." * "This receiver is quite sensitive on SW and I found that using an external antenna overloaded it." iane ~ RHF . . = = = "Dave" wrote in message = = = ... - - - - - S N I P - - - - - Sorry, forgot to include that information. I am using a DX-402 (aka Sangean ATS-505). I honestly wondered about that, but hesitated to shorten the wire because I would (obvioiusly) lose some sensitivity, and really like being able to pick up VOK's English broadcasts to Central America. Only problem is the noise that makes it difficult to single out. Thanks, Dave |
"starman" wrote in message ... Dave wrote: Wow. Thank you for these concise and clear directions. One thing though, I really don't *think* I am overloading the set. Only problem I have is digging the weak (but desired) signals our of the background noise surrounding them. In another post I mentioned Voice of Korea's Central and South American broadcast as the point of interest. It is just at the same level as the background noise that doesn't interfere with other broadcasts like the BBC on 5975 kHz or Radio Havana, Cuba on 9820 kHz (or Radio China International, originally from Taiwan and rebroadcast through some place in Florida, which frequency I can't remember at the moment.) It is only the weak signals I am having trouble with. If I tune into WWV our of Ft. Collins CO I can barely make out some out-of-band signals coming in, but they are so weak as to be vanishing. Does this still sound like overloading? Because the troublesom signals are also very weak, I am thinking that a preselector will probably take care of my problems. (I am still tempted to abandon my random wire and install your suggested antenna just because it sounds so much more sophisticated. Will let you know.) Thanks for the feedback. Dave If you don't hear that background noise with the whip antenna, the problem is almost certainly too much signal (overloading) from the external antenna. That's why I recommended a passive preselector. Okay, that I can understand. If I leave the radio switched to DX while listening to BBC etc, the background noise is still there, but like the desired signal is at least twice the strength it would be with the whip alone. Therefore I switch to Local, which blanks out the noise. WithVOK to Central and South America I can't do that without losing the desired broadcast as well. Will a preselector still help (at least somewhat?) or is this just the way it is? Thanks, Dave |
Just printed your instructions in prep for a trip to the store, and have one
question: The twin-lead is 300 ohm, connected to a 300/75 ohm matching transformer, connected to 75 ohm coax. Then the coax is connectect to another 75/300 ohm matching transformer, which is connected to the 1/8" mono plug to plug into the external antenna jack? Is the 1/8" jack a 300 ohm impedance connection? Somehow I thought it would be 50 or 75 ohms, like coax. Do I need some 300 ohm coax to put between the second transformer and the plug? Thanks, Dave "RHF" wrote in message om... DAVE, So you have a Sangean ATS -505 and your 'problems' are Antenna Overload and Noise Levels. * Consider a 'smaller' shorter Antenna will reduce the overload problems. * Consider a Low Noise Antenna Design will reduce the noise problems. {LOW NOISE SWL ANTENNA - popularized by John Doty} http://groups.yahoo.com/group/Shortw...enna/message/2 http://www.anarc.org/naswa/badx/ante...e_antenna.html For a simple 'external' Shortwave Antenna to use with the Sangean ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack External Shortwave Antenna Input. Consider a Random Wire Antenna using a Matching Transformer and Ground for Low Noise and Wide Range Frequency Coverage. PARTS: Here is a simple SWL Antenna Idea using a few common RadioShack TV Antenna type parts: Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.) Catalog #: 274-286 = 1/8" Mono (Phone) Plug Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors NOTE: This is an 'improved' Random Wire SWL Antenna using "TV" Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in or near most modern homes/buildings. EXTERNAL "OUTSIDE" SWL ANTENNA: The Antenna [Loop] Element is Stretched outside Horizontally or in the shape of an Inverted "L". The Antenna [Loop] Element is formed by connecting the two ends of the Far-End of the 300 Ohm TV Twin Lead. This forms a continuous single skinny horizontal flat loop going out and back. This also represents a Balance 300 Ohm Load to match-up with the 300 Ohm Matching Transformer. The 300 Ohm Leads of the Matching Transformer connects to the Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector of the Matching Transformer is connected to the 75 Ohm Coax Cable. The 75 Ohm Coax Cable acts as the Lead-In from the Outside to inside the house to the radio shack. The other end of the 75 Ohm Coax Cable is connected to the 75 Ohm F Connector of the Matching Transformer. The Radio-End of the Coax Cable F Connector would connect to a 75 to 300 Ohm Matching Transformer; and then into a 1/8" Mono-Plug to plug into the Radio. NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop Antenna should balance-cancel-reduce most man made noise and be Omni-Directional. GROUND: Find a Grounding Point within/about your dwelling. Secure a good Grounding Point for your Radio and Antenna. Run a Heavy & Short Ground Wire to your Radio. Locate the Ground Terminal on your Radio. Attach/Secure the Ground Wire to the Coax Cable and/or the Radio's Ground Terminal. FWIW: This Antenna using common TV Antenna type parts should be effective as SWL Antennas above 5MHz and beyond 30MHz. iane ~ RHF . Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond - The Beyond ! . . = = = "Dave" wrote in message = = = ... I recently hooked up a thirty-six foot (plus or minus a couple of feet) piece of four-stranded wire with alligator clip to the internal "whip" antenna of my portable shortwave receiver, for the extra performance such a device offered. It works so well that I now cannot usually use my "DX" setting because of all the background noise (sounds like hundreds of other broadcasts vying for attention.) I don't know the frequency source of all this background noise, but would like to filter out as much of it as I can. One manufacturer of a similar "wind-up" antenna adds a capacitor to the wire in order to lower the resonance frequency of the wire. If I were going to try something similar (adding a capacitor, in series) in an attempt to bring the resonance of the wire down into the 30 MHz range, what size (roughly) capacitor should I use? Should I just try a few with different ranges, or does anyone here have any suggestions? TIA Cross-posted between sci.electronics.basics and rec.radio.shortwave Dave . |
Dave wrote:
"starman" wrote in message If you don't hear that background noise with the whip antenna, the problem is almost certainly too much signal (overloading) from the external antenna. That's why I recommended a passive preselector. Okay, that I can understand. If I leave the radio switched to DX while listening to BBC etc, the background noise is still there, but like the desired signal is at least twice the strength it would be with the whip alone. Therefore I switch to Local, which blanks out the noise. WithVOK to Central and South America I can't do that without losing the desired broadcast as well. Will a preselector still help (at least somewhat?) or is this just the way it is? Thanks, Dave Your describing (above) the classic symptom of overloading. Make the noise comparison using just the receiver's whip antenna first, then connect the external antenna. You can leave it set to DX for both antennas. If you hear the noise *only* when using the external antenna, the problem is overloading. The noise you're hearing is coming from many intermodulation products caused by insufficient dynamic range when using an external antenna. A passive preselector will allow you to use the external antenna without the noise. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"starman" wrote in message ... Dave wrote: "starman" wrote in message If you don't hear that background noise with the whip antenna, the problem is almost certainly too much signal (overloading) from the external antenna. That's why I recommended a passive preselector. Okay, that I can understand. If I leave the radio switched to DX while listening to BBC etc, the background noise is still there, but like the desired signal is at least twice the strength it would be with the whip alone. Therefore I switch to Local, which blanks out the noise. WithVOK to Central and South America I can't do that without losing the desired broadcast as well. Will a preselector still help (at least somewhat?) or is this just the way it is? Thanks, Dave Your describing (above) the classic symptom of overloading. Make the noise comparison using just the receiver's whip antenna first, then connect the external antenna. You can leave it set to DX for both antennas. If you hear the noise *only* when using the external antenna, the problem is overloading. The noise you're hearing is coming from many intermodulation products caused by insufficient dynamic range when using an external antenna. A passive preselector will allow you to use the external antenna without the noise. Hello Starman, Sorry I forgot to respond to you earlier. I did this a while back, when you or someone else first suggested it, and I hear hte same background noise with the whip that I hear with the external antenna, it (along with the other signals, inaudable with the whip alone) is just louder with the external. That is why I am wanting to use the passive preselector. I am thinking that will reduce the noise without reducing the desired signal. Dave |
DAVE,
At the Radio-End of the 75 Ohm Coax Cable "F" Connector you can use a standard 75-300 Ohm Matching Transformer and then connect it to a Mini-TV External Antenna Adapter. [ RadioShack {Canada} Catalog #: 15-1148 = 75 to 300 Ohm Mini-Plug Adapter ] MINI-PLUG-ADAPTER= http://tinyurl.com/23nsh FWIW: Some RadioShacks and other electronics stores have an "Adapter" that directly connects an "F" Connector to a /18" Mono-Phone-Jack. Please Note: That a 'connection' to a good earthen Ground is needed to one of the "F" Connectors of the 75 Ohm Coax Cable. You can use a #14 Wire with a RadioShack Catalog #: 278-002 Heavy-Duty Claw Insulated Test/Jumper Cable Sets. Or, simply use several windings of bare wire wrapped around one of the "F" Connectors with a small metal hose clamp to secure the wire. iane ~ RHF .. .. = = = "Dave" wrote in message = = = ... Just printed your instructions in prep for a trip to the store, and have one question: The twin-lead is 300 ohm, connected to a 300/75 ohm matching transformer, connected to 75 ohm coax. Then the coax is connectect to another 75/300 ohm matching transformer, which is connected to the 1/8" mono plug to plug into the external antenna jack? Is the 1/8" jack a 300 ohm impedance connection? Somehow I thought it would be 50 or 75 ohms, like coax. Do I need some 300 ohm coax to put between the second transformer and the plug? Thanks, Dave "RHF" wrote in message om... DAVE, So you have a Sangean ATS -505 and your 'problems' are Antenna Overload and Noise Levels. * Consider a 'smaller' shorter Antenna will reduce the overload problems. * Consider a Low Noise Antenna Design will reduce the noise problems. {LOW NOISE SWL ANTENNA - popularized by John Doty} http://groups.yahoo.com/group/Shortw...enna/message/2 http://www.anarc.org/naswa/badx/ante...e_antenna.html For a simple 'external' Shortwave Antenna to use with the Sangean ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack External Shortwave Antenna Input. Consider a Random Wire Antenna using a Matching Transformer and Ground for Low Noise and Wide Range Frequency Coverage. PARTS: Here is a simple SWL Antenna Idea using a few common RadioShack TV Antenna type parts: Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.) Catalog #: 274-286 = 1/8" Mono (Phone) Plug Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors NOTE: This is an 'improved' Random Wire SWL Antenna using "TV" Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in or near most modern homes/buildings. EXTERNAL "OUTSIDE" SWL ANTENNA: The Antenna [Loop] Element is Stretched outside Horizontally or in the shape of an Inverted "L". The Antenna [Loop] Element is formed by connecting the two ends of the Far-End of the 300 Ohm TV Twin Lead. This forms a continuous single skinny horizontal flat loop going out and back. This also represents a Balance 300 Ohm Load to match-up with the 300 Ohm Matching Transformer. The 300 Ohm Leads of the Matching Transformer connects to the Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector of the Matching Transformer is connected to the 75 Ohm Coax Cable. The 75 Ohm Coax Cable acts as the Lead-In from the Outside to inside the house to the radio shack. The other end of the 75 Ohm Coax Cable is connected to the 75 Ohm F Connector of the Matching Transformer. The Radio-End of the Coax Cable F Connector would connect to a 75 to 300 Ohm Matching Transformer; and then into a 1/8" Mono-Plug to plug into the Radio. NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop Antenna should balance-cancel-reduce most man made noise and be Omni-Directional. GROUND: Find a Grounding Point within/about your dwelling. Secure a good Grounding Point for your Radio and Antenna. Run a Heavy & Short Ground Wire to your Radio. Locate the Ground Terminal on your Radio. Attach/Secure the Ground Wire to the Coax Cable and/or the Radio's Ground Terminal. FWIW: This Antenna using common TV Antenna type parts should be effective as SWL Antennas above 5MHz and beyond 30MHz. iane ~ RHF . Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond - The Beyond ! . . = = = "Dave" wrote in message = = = ... I recently hooked up a thirty-six foot (plus or minus a couple of feet) piece of four-stranded wire with alligator clip to the internal "whip" antenna of my portable shortwave receiver, for the extra performance such a device offered. It works so well that I now cannot usually use my "DX" setting because of all the background noise (sounds like hundreds of other broadcasts vying for attention.) I don't know the frequency source of all this background noise, but would like to filter out as much of it as I can. One manufacturer of a similar "wind-up" antenna adds a capacitor to the wire in order to lower the resonance frequency of the wire. If I were going to try something similar (adding a capacitor, in series) in an attempt to bring the resonance of the wire down into the 30 MHz range, what size (roughly) capacitor should I use? Should I just try a few with different ranges, or does anyone here have any suggestions? TIA Cross-posted between sci.electronics.basics and rec.radio.shortwave Dave . |
"RHF" wrote in message om... DAVE, At the Radio-End of the 75 Ohm Coax Cable "F" Connector you can use a standard 75-300 Ohm Matching Transformer and then connect it to a Mini-TV External Antenna Adapter. [ RadioShack {Canada} Catalog #: 15-1148 = 75 to 300 Ohm Mini-Plug Adapter ] MINI-PLUG-ADAPTER= http://tinyurl.com/23nsh FWIW: Some RadioShacks and other electronics stores have an "Adapter" that directly connects an "F" Connector to a /18" Mono-Phone-Jack. Please Note: That a 'connection' to a good earthen Ground is needed to one of the "F" Connectors of the 75 Ohm Coax Cable. You can use a #14 Wire with a RadioShack Catalog #: 278-002 Heavy-Duty Claw Insulated Test/Jumper Cable Sets. Or, simply use several windings of bare wire wrapped around one of the "F" Connectors with a small metal hose clamp to secure the wire. iane ~ RHF . . = = = "Dave" wrote in message = = = ... Just printed your instructions in prep for a trip to the store, and have one question: The twin-lead is 300 ohm, connected to a 300/75 ohm matching transformer, connected to 75 ohm coax. Then the coax is connectect to another 75/300 ohm matching transformer, which is connected to the 1/8" mono plug to plug into the external antenna jack? Is the 1/8" jack a 300 ohm impedance connection? Somehow I thought it would be 50 or 75 ohms, like coax. Do I need some 300 ohm coax to put between the second transformer and the plug? Thanks, Dave "RHF" wrote in message om... DAVE, So you have a Sangean ATS -505 and your 'problems' are Antenna Overload and Noise Levels. * Consider a 'smaller' shorter Antenna will reduce the overload problems. * Consider a Low Noise Antenna Design will reduce the noise problems. {LOW NOISE SWL ANTENNA - popularized by John Doty} http://groups.yahoo.com/group/Shortw...enna/message/2 http://www.anarc.org/naswa/badx/ante...e_antenna.html For a simple 'external' Shortwave Antenna to use with the Sangean ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack External Shortwave Antenna Input. Consider a Random Wire Antenna using a Matching Transformer and Ground for Low Noise and Wide Range Frequency Coverage. PARTS: Here is a simple SWL Antenna Idea using a few common RadioShack TV Antenna type parts: Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.) Catalog #: 274-286 = 1/8" Mono (Phone) Plug Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors NOTE: This is an 'improved' Random Wire SWL Antenna using "TV" Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in or near most modern homes/buildings. EXTERNAL "OUTSIDE" SWL ANTENNA: The Antenna [Loop] Element is Stretched outside Horizontally or in the shape of an Inverted "L". The Antenna [Loop] Element is formed by connecting the two ends of the Far-End of the 300 Ohm TV Twin Lead. This forms a continuous single skinny horizontal flat loop going out and back. This also represents a Balance 300 Ohm Load to match-up with the 300 Ohm Matching Transformer. The 300 Ohm Leads of the Matching Transformer connects to the Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector of the Matching Transformer is connected to the 75 Ohm Coax Cable. The 75 Ohm Coax Cable acts as the Lead-In from the Outside to inside the house to the radio shack. The other end of the 75 Ohm Coax Cable is connected to the 75 Ohm F Connector of the Matching Transformer. The Radio-End of the Coax Cable F Connector would connect to a 75 to 300 Ohm Matching Transformer; and then into a 1/8" Mono-Plug to plug into the Radio. NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop Antenna should balance-cancel-reduce most man made noise and be Omni-Directional. GROUND: Find a Grounding Point within/about your dwelling. Secure a good Grounding Point for your Radio and Antenna. Run a Heavy & Short Ground Wire to your Radio. Locate the Ground Terminal on your Radio. Attach/Secure the Ground Wire to the Coax Cable and/or the Radio's Ground Terminal. FWIW: This Antenna using common TV Antenna type parts should be effective as SWL Antennas above 5MHz and beyond 30MHz. iane ~ RHF . Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond - The Beyond ! . . = = = "Dave" wrote in message = = = ... I recently hooked up a thirty-six foot (plus or minus a couple of feet) piece of four-stranded wire with alligator clip to the internal "whip" antenna of my portable shortwave receiver, for the extra performance such a device offered. It works so well that I now cannot usually use my "DX" setting because of all the background noise (sounds like hundreds of other broadcasts vying for attention.) I don't know the frequency source of all this background noise, but would like to filter out as much of it as I can. One manufacturer of a similar "wind-up" antenna adds a capacitor to the wire in order to lower the resonance frequency of the wire. If I were going to try something similar (adding a capacitor, in series) in an attempt to bring the resonance of the wire down into the 30 MHz range, what size (roughly) capacitor should I use? Should I just try a few with different ranges, or does anyone here have any suggestions? TIA Cross-posted between sci.electronics.basics and rec.radio.shortwave Dave . |
Argh. I just posted an empty message. Sorry. Please ignore.
Thanks for the info. I picked up a 300/75 ohm mini-plug adapter at the store, but failed to get the second 75/300 ohm matching transformer to go between it and the coax. Tomorrow. Question: I have an odd situation, and can either install a 1/4 wave dipole or a half-wave "random" wire loop (I think). Right now the grounding rod is immediately below where the dipole would go, and I think I could drop the 300 ohm twin-lead down to it where I would ground one side (I think I have this right, please correct me if I am wrong). At that same point I would ground the shield of the coax, and hook the other side of the dipole to the coax center conductor. Coax would travel 10 feet or so to my window and the radio. Other option involves moving the grounding rod and doing something similar with the twin-lead as a long loop, grounding one side of that and coax from the other side of the window. Assuming these are workable ideas, which do you think would work best? Again, [please don't hesitate to tell me if I am full of crap. RF is new to me. I really do appreciate your help. Like I said before, RF is totally new to me. Thanks, Dave "RHF" wrote in message om... DAVE, At the Radio-End of the 75 Ohm Coax Cable "F" Connector you can use a standard 75-300 Ohm Matching Transformer and then connect it to a Mini-TV External Antenna Adapter. [ RadioShack {Canada} Catalog #: 15-1148 = 75 to 300 Ohm Mini-Plug Adapter ] MINI-PLUG-ADAPTER= http://tinyurl.com/23nsh FWIW: Some RadioShacks and other electronics stores have an "Adapter" that directly connects an "F" Connector to a /18" Mono-Phone-Jack. Please Note: That a 'connection' to a good earthen Ground is needed to one of the "F" Connectors of the 75 Ohm Coax Cable. You can use a #14 Wire with a RadioShack Catalog #: 278-002 Heavy-Duty Claw Insulated Test/Jumper Cable Sets. Or, simply use several windings of bare wire wrapped around one of the "F" Connectors with a small metal hose clamp to secure the wire. iane ~ RHF . . = = = "Dave" wrote in message = = = ... Just printed your instructions in prep for a trip to the store, and have one question: The twin-lead is 300 ohm, connected to a 300/75 ohm matching transformer, connected to 75 ohm coax. Then the coax is connectect to another 75/300 ohm matching transformer, which is connected to the 1/8" mono plug to plug into the external antenna jack? Is the 1/8" jack a 300 ohm impedance connection? Somehow I thought it would be 50 or 75 ohms, like coax. Do I need some 300 ohm coax to put between the second transformer and the plug? Thanks, Dave "RHF" wrote in message om... DAVE, So you have a Sangean ATS -505 and your 'problems' are Antenna Overload and Noise Levels. * Consider a 'smaller' shorter Antenna will reduce the overload problems. * Consider a Low Noise Antenna Design will reduce the noise problems. {LOW NOISE SWL ANTENNA - popularized by John Doty} http://groups.yahoo.com/group/Shortw...enna/message/2 http://www.anarc.org/naswa/badx/ante...e_antenna.html For a simple 'external' Shortwave Antenna to use with the Sangean ATS-505 'portable' Shortwave Radio, using the 1/8" Mono-Jack External Shortwave Antenna Input. Consider a Random Wire Antenna using a Matching Transformer and Ground for Low Noise and Wide Range Frequency Coverage. PARTS: Here is a simple SWL Antenna Idea using a few common RadioShack TV Antenna type parts: Catalog #: 15-1174 = 25~50 Foot 300 Ohm (Flat) TV Twin-Lead Catalog #: 15-1230 = 75 to 300 Ohm Matching Transformer (2 Ea.) Catalog #: 274-286 = 1/8" Mono (Phone) Plug Catalog #: Catalog #: 15-1579 = 25~50 Foot Coax Cable with F Connectors NOTE: This is an 'improved' Random Wire SWL Antenna using "TV" Parts for 'reducing' Man Made Noise (RFI EMF) that is generated in or near most modern homes/buildings. EXTERNAL "OUTSIDE" SWL ANTENNA: The Antenna [Loop] Element is Stretched outside Horizontally or in the shape of an Inverted "L". The Antenna [Loop] Element is formed by connecting the two ends of the Far-End of the 300 Ohm TV Twin Lead. This forms a continuous single skinny horizontal flat loop going out and back. This also represents a Balance 300 Ohm Load to match-up with the 300 Ohm Matching Transformer. The 300 Ohm Leads of the Matching Transformer connects to the Near-Ends of the Loop Antenna Element. The 75 Ohm F Connector of the Matching Transformer is connected to the 75 Ohm Coax Cable. The 75 Ohm Coax Cable acts as the Lead-In from the Outside to inside the house to the radio shack. The other end of the 75 Ohm Coax Cable is connected to the 75 Ohm F Connector of the Matching Transformer. The Radio-End of the Coax Cable F Connector would connect to a 75 to 300 Ohm Matching Transformer; and then into a 1/8" Mono-Plug to plug into the Radio. NOTE: Using the 300 Ohm TV Twin Lead in a Skinny Flat Loop Antenna should balance-cancel-reduce most man made noise and be Omni-Directional. GROUND: Find a Grounding Point within/about your dwelling. Secure a good Grounding Point for your Radio and Antenna. Run a Heavy & Short Ground Wire to your Radio. Locate the Ground Terminal on your Radio. Attach/Secure the Ground Wire to the Coax Cable and/or the Radio's Ground Terminal. FWIW: This Antenna using common TV Antenna type parts should be effective as SWL Antennas above 5MHz and beyond 30MHz. iane ~ RHF . Some Say: On A Clear Day You Can See Forever. http://groups.yahoo.com/group/Shortw...na/message/502 I BELIEVE: On A Clear Night... You Can Hear Forever and Beyond - The Beyond ! . . = = = "Dave" wrote in message = = = ... I recently hooked up a thirty-six foot (plus or minus a couple of feet) piece of four-stranded wire with alligator clip to the internal "whip" antenna of my portable shortwave receiver, for the extra performance such a device offered. It works so well that I now cannot usually use my "DX" setting because of all the background noise (sounds like hundreds of other broadcasts vying for attention.) I don't know the frequency source of all this background noise, but would like to filter out as much of it as I can. One manufacturer of a similar "wind-up" antenna adds a capacitor to the wire in order to lower the resonance frequency of the wire. If I were going to try something similar (adding a capacitor, in series) in an attempt to bring the resonance of the wire down into the 30 MHz range, what size (roughly) capacitor should I use? Should I just try a few with different ranges, or does anyone here have any suggestions? TIA Cross-posted between sci.electronics.basics and rec.radio.shortwave Dave . |
= = = "Dave" wrote in message
= = = ... Argh. I just posted an empty message. Sorry. Please ignore. Thanks for the info. I picked up a 300/75 ohm mini-plug adapter at the store, but failed to get the second 75/300 ohm matching transformer to go between it and the coax. Tomorrow. Question: I have an odd situation, and can either install a 1/4 wave dipole or a half-wave "random" wire loop (I think). A "Random" Wire Antenna is simply that = Any Length that FITS the Space that is Available to put up and Antenna. For these general types of Low Noise Antennas. The Inverted "L" {Shaped} Antenna lends itself to the design the best. Run the Horizontal Arm for as long as you can at your roof line. Run the Vertial Leg down to your Ground Rod Location. Make your 'primary' Grounding Point "Connection". Run your Coax Cable from the Grounding Point to your Radio. .. .. Right now the grounding rod is immediately below where the dipole would go, and I think I could drop the 300 ohm twin-lead down to it where I would ground one side (I think I have this right, please correct me if I am wrong). Initially do NOT Ground the 300 Ohm Twin Lead. [ This is the Antenna Side of the Matching Transformer. ] The Near-End of the 300 Ohm Twin Lead is connected across the 300 Ohm-Side of the Matching Transformer; and the other Far-End of the 300 Ohm Twin Lead Wires are Connected (Joined) Together. This forms a Long Shinny Loop Antenna Element. FWIW: This is a very 'quiet' Antenna (almost sounds dead) until you get spot on the frequency and then the signal is there. .. .. At that same point I would ground the shield of the coax, and hook the other side of the dipole to the coax center conductor. Coax would travel 10 feet or so to my window and the radio. First simply try Grounding the Outer-Shield of the Coax Cable ONLY. .. .. Other option involves moving the grounding rod IF - You move the Ground Rod. Place it so you can have an Inverted "L" Antenna with the longest Horizontal Arm 'possible'. (30 60-90 120 Feet) iane ~ RHF .. .. and doing something similar with the twin-lead as a long loop, grounding one side of that and coax from the other side of the window. Assuming these are workable ideas, which do you think would work best? Again, [please don't hesitate to tell me if I am full of crap. RF is new to me. I really do appreciate your help. Like I said before, RF is totally new to me. Thanks, Dave |
An idea just occurred to me. Since you (RHF) are the main one I am talking
with on this subject at this point, and since I did join the Yahoo! Shortwave Antenna group, I am going to try (that is, do my best) to move this over to that group. All posts from this point on, at least on this particular thread, will be made there. This text will be posted there in a few minutes, alongwith a couple more questions and clarifications. Thanks for introducing me to that group, which I am trying to get more into, and thanks for your help so far. Dave "RHF" wrote in message om... = = = "Dave" wrote in message = = = ... Argh. I just posted an empty message. Sorry. Please ignore. Thanks for the info. I picked up a 300/75 ohm mini-plug adapter at the store, but failed to get the second 75/300 ohm matching transformer to go between it and the coax. Tomorrow. Question: I have an odd situation, and can either install a 1/4 wave dipole or a half-wave "random" wire loop (I think). A "Random" Wire Antenna is simply that = Any Length that FITS the Space that is Available to put up and Antenna. For these general types of Low Noise Antennas. The Inverted "L" {Shaped} Antenna lends itself to the design the best. Run the Horizontal Arm for as long as you can at your roof line. Run the Vertial Leg down to your Ground Rod Location. Make your 'primary' Grounding Point "Connection". Run your Coax Cable from the Grounding Point to your Radio. . . Right now the grounding rod is immediately below where the dipole would go, and I think I could drop the 300 ohm twin-lead down to it where I would ground one side (I think I have this right, please correct me if I am wrong). Initially do NOT Ground the 300 Ohm Twin Lead. [ This is the Antenna Side of the Matching Transformer. ] The Near-End of the 300 Ohm Twin Lead is connected across the 300 Ohm-Side of the Matching Transformer; and the other Far-End of the 300 Ohm Twin Lead Wires are Connected (Joined) Together. This forms a Long Shinny Loop Antenna Element. FWIW: This is a very 'quiet' Antenna (almost sounds dead) until you get spot on the frequency and then the signal is there. . . At that same point I would ground the shield of the coax, and hook the other side of the dipole to the coax center conductor. Coax would travel 10 feet or so to my window and the radio. First simply try Grounding the Outer-Shield of the Coax Cable ONLY. . . Other option involves moving the grounding rod IF - You move the Ground Rod. Place it so you can have an Inverted "L" Antenna with the longest Horizontal Arm 'possible'. (30 60-90 120 Feet) iane ~ RHF . . and doing something similar with the twin-lead as a long loop, grounding one side of that and coax from the other side of the window. Assuming these are workable ideas, which do you think would work best? Again, [please don't hesitate to tell me if I am full of crap. RF is new to me. I really do appreciate your help. Like I said before, RF is totally new to me. Thanks, Dave |
And what of the people just fallowing along? Don't suggest Yahoo. It's not
an option. "Dave" wrote in message ... An idea just occurred to me. Since you (RHF) are the main one I am talking with on this subject at this point, and since I did join the Yahoo! Shortwave Antenna group, I am going to try (that is, do my best) to move this over to that group. All posts from this point on, at least on this particular thread, will be made there. This text will be posted there in a few minutes, alongwith a couple more questions and clarifications. Thanks for introducing me to that group, which I am trying to get more into, and thanks for your help so far. Dave "RHF" wrote in message om... = = = "Dave" wrote in message = = = ... Argh. I just posted an empty message. Sorry. Please ignore. Thanks for the info. I picked up a 300/75 ohm mini-plug adapter at the store, but failed to get the second 75/300 ohm matching transformer to go between it and the coax. Tomorrow. Question: I have an odd situation, and can either install a 1/4 wave dipole or a half-wave "random" wire loop (I think). A "Random" Wire Antenna is simply that = Any Length that FITS the Space that is Available to put up and Antenna. For these general types of Low Noise Antennas. The Inverted "L" {Shaped} Antenna lends itself to the design the best. Run the Horizontal Arm for as long as you can at your roof line. Run the Vertial Leg down to your Ground Rod Location. Make your 'primary' Grounding Point "Connection". Run your Coax Cable from the Grounding Point to your Radio. . . Right now the grounding rod is immediately below where the dipole would go, and I think I could drop the 300 ohm twin-lead down to it where I would ground one side (I think I have this right, please correct me if I am wrong). Initially do NOT Ground the 300 Ohm Twin Lead. [ This is the Antenna Side of the Matching Transformer. ] The Near-End of the 300 Ohm Twin Lead is connected across the 300 Ohm-Side of the Matching Transformer; and the other Far-End of the 300 Ohm Twin Lead Wires are Connected (Joined) Together. This forms a Long Shinny Loop Antenna Element. FWIW: This is a very 'quiet' Antenna (almost sounds dead) until you get spot on the frequency and then the signal is there. . . At that same point I would ground the shield of the coax, and hook the other side of the dipole to the coax center conductor. Coax would travel 10 feet or so to my window and the radio. First simply try Grounding the Outer-Shield of the Coax Cable ONLY. . . Other option involves moving the grounding rod IF - You move the Ground Rod. Place it so you can have an Inverted "L" Antenna with the longest Horizontal Arm 'possible'. (30 60-90 120 Feet) iane ~ RHF . . and doing something similar with the twin-lead as a long loop, grounding one side of that and coax from the other side of the window. Assuming these are workable ideas, which do you think would work best? Again, [please don't hesitate to tell me if I am full of crap. RF is new to me. I really do appreciate your help. Like I said before, RF is totally new to me. Thanks, Dave |
Dave wrote:
An idea just occurred to me. Since you (RHF) are the main one I am talking with on this subject at this point, and since I did join the Yahoo! Shortwave Antenna group, I am going to try (that is, do my best) to move this over to that group. All posts from this point on, at least on this particular thread, will be made there. I don't do Yahoo groups so I'll say goodbye Dave. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Okay, I'll try to keep you posted. Here's what I asked on Yahoo!
OKAY, here are the new questions and clarifications... Thanks for clearing up for me why it is called a random wire. I thought that was just what they called it when it wasn't 1/4 or 1/2 wavelength. I realized something today- I think I am actually talking about installing a HALF-WAVE dipole, not a 1/4 wave. Since it is twin-lead I am talking about, and since it is going to be joined at the far end, each leg would be twice the 1/4 wavelength of the physical cable. Am I right here? Correct me if I am wrong, but you do ground one side of a dipole, right? So one leg would be grounded along with the shield of the coax, right? What I am visualizing is two pieces of twin-lead, one called A (left) and the other called B (right.) A would have one side of one end soldered to the ground rod (call this the "near" end) with the other side of that end hanging out in space. The rest of that piece of twin-lead (side A) would go up the side of my house to the eaves and over several meters. The far end of A would have the two conductors soldered together. B would have one side of the "near" end attached to the appropriate lead of a 300/75 ohm matching transformer, which has it's other lead soldered to the grounding rod and goes to 75 ohm coax. The other side of the "near" end of B hangs out in space. B would then go up the side of the house to the eaves, just like A, but would then stretch several meters in the other direction. The "far" end of B would also have the two conductors soldered together. Each leg is a little over 15 meters long (counting the part that goes up as well as the part that goes over), which would make the whole dipole a half-wavelength for some frequency slightly below 10 MHz. (Have I got this right?) The coax would travel approx. 4 meters to my window, where it would go through another matching transformer and into the external antenna input of the radio. Wouldn't that be a half-wave dipole? Would it matter that the side of the house is covered in steel siding, against which it would be lying? Would this work, or would an inverted L still be better (or quieter)? I could put the grounding rod immediately outside my window, which might enable me to make the long leg of the L somewhat longer than the combined 30 meters of the dipole. That would make for a shorter run of coax, but the soil would be drier thereby making for a poorer ground (where it is now, the grounding rod sits next to the output of a downspout.) If I went with the inverted L (with joined conducters on the far end to make a loop) would I still ground one side of the twin-lead? Do you ground one side of a loop? Okay, I've written War and Peace. Sorry for the great number of questions, I'm just trying to understand the fundamentals of installing an antenna. I hope I am not trying your patience. Thanks, Dave I also posted another message asking if anyone had read the book called Shortwave Listener's Antenna Handbook published by TAB books in '82. I saw it on Amazon.com, but they didn't have any ratings for it. If anyone HERE has read it, please share your opinion with me. Dave "CW" wrote in message ... And what of the people just fallowing along? Don't suggest Yahoo. It's not an option. "Dave" wrote in message ... An idea just occurred to me. Since you (RHF) are the main one I am talking with on this subject at this point, and since I did join the Yahoo! Shortwave Antenna group, I am going to try (that is, do my best) to move this over to that group. All posts from this point on, at least on this particular thread, will be made there. This text will be posted there in a few minutes, alongwith a couple more questions and clarifications. Thanks for introducing me to that group, which I am trying to get more into, and thanks for your help so far. Dave "RHF" wrote in message om... = = = "Dave" wrote in message = = = ... Argh. I just posted an empty message. Sorry. Please ignore. Thanks for the info. I picked up a 300/75 ohm mini-plug adapter at the store, but failed to get the second 75/300 ohm matching transformer to go between it and the coax. Tomorrow. Question: I have an odd situation, and can either install a 1/4 wave dipole or a half-wave "random" wire loop (I think). A "Random" Wire Antenna is simply that = Any Length that FITS the Space that is Available to put up and Antenna. For these general types of Low Noise Antennas. The Inverted "L" {Shaped} Antenna lends itself to the design the best. Run the Horizontal Arm for as long as you can at your roof line. Run the Vertial Leg down to your Ground Rod Location. Make your 'primary' Grounding Point "Connection". Run your Coax Cable from the Grounding Point to your Radio. . . Right now the grounding rod is immediately below where the dipole would go, and I think I could drop the 300 ohm twin-lead down to it where I would ground one side (I think I have this right, please correct me if I am wrong). Initially do NOT Ground the 300 Ohm Twin Lead. [ This is the Antenna Side of the Matching Transformer. ] The Near-End of the 300 Ohm Twin Lead is connected across the 300 Ohm-Side of the Matching Transformer; and the other Far-End of the 300 Ohm Twin Lead Wires are Connected (Joined) Together. This forms a Long Shinny Loop Antenna Element. FWIW: This is a very 'quiet' Antenna (almost sounds dead) until you get spot on the frequency and then the signal is there. . . At that same point I would ground the shield of the coax, and hook the other side of the dipole to the coax center conductor. Coax would travel 10 feet or so to my window and the radio. First simply try Grounding the Outer-Shield of the Coax Cable ONLY. . . Other option involves moving the grounding rod IF - You move the Ground Rod. Place it so you can have an Inverted "L" Antenna with the longest Horizontal Arm 'possible'. (30 60-90 120 Feet) iane ~ RHF . . and doing something similar with the twin-lead as a long loop, grounding one side of that and coax from the other side of the window. Assuming these are workable ideas, which do you think would work best? Again, [please don't hesitate to tell me if I am full of crap. RF is new to me. I really do appreciate your help. Like I said before, RF is totally new to me. Thanks, Dave |
"starman" wrote in message ... Dave wrote: An idea just occurred to me. Since you (RHF) are the main one I am talking with on this subject at this point, and since I did join the Yahoo! Shortwave Antenna group, I am going to try (that is, do my best) to move this over to that group. All posts from this point on, at least on this particular thread, will be made there. I don't do Yahoo groups so I'll say goodbye Dave. HANG ON! I didn't know anyone else was interested. Can I just try to post my questions here as well? If you guys want, I'll post his answers as well. See my previous post CW for the questions I asked RHF in the Yahoo! group. Didn't mean to cut anyone out. Just thought I was wasting space. Sorry. Dave |
Dave wrote:
Okay, I'll try to keep you posted. Here's what I asked on Yahoo! OKAY, here are the new questions and clarifications... Thanks for clearing up for me why it is called a random wire. I thought that was just what they called it when it wasn't 1/4 or 1/2 wavelength. I realized something today- I think I am actually talking about installing a HALF-WAVE dipole, not a 1/4 wave. Since it is twin-lead I am talking about, and since it is going to be joined at the far end, each leg would be twice the 1/4 wavelength of the physical cable. Am I right here? It sounds like you're thinking about making a folded dipole. The total length of the twinlead folded dipole should still be a half wavelength but the impedance at the connection point (middle) for the downlead changes from about 50-ohms for a simple dipole to 300-ohms for the folded type. This means a 50 or 75-ohm coax lead would not be suitable without a 6:1 impedance matching transformer. The higher impedance side of the transformer connects to the middle of the dipole and the low side goes to the coax. Correct me if I am wrong, but you do ground one side of a dipole, right? So one leg would be grounded along with the shield of the coax, right? It's not necessary to ground the coax shield from a dipole because it's a balanced antenna design. However you may want to ground the chassis of the receiver itself. The coax should be connnected to a balanced antenna input on the receiver. This means the coax shield is not directly connected (grounded) to the receiver's chassis. You should be aware that some receiver's don't have the proper input connection for a balanced antenna like a dipole. In that case you would just connect the coax to whatever external antenna input there is and not be concerned whether the coax shield is grounded to the chassis or not. It's not the ideal way to do it, but sometimes you don't have any choice. I forgot what receiver you're using. What I am visualizing is two pieces of twin-lead, one called A (left) and the other called B (right.) A would have one side of one end soldered to the ground rod (call this the "near" end) with the other side of that end hanging out in space. The rest of that piece of twin-lead (side A) would go up the side of my house to the eaves and over several meters. The far end of A would have the two conductors soldered together. B would have one side of the "near" end attached to the appropriate lead of a 300/75 ohm matching transformer, which has it's other lead soldered to the grounding rod and goes to 75 ohm coax. The other side of the "near" end of B hangs out in space. B would then go up the side of the house to the eaves, just like A, but would then stretch several meters in the other direction. The "far" end of B would also have the two conductors soldered together. Each leg is a little over 15 meters long (counting the part that goes up as well as the part that goes over), which would make the whole dipole a half-wavelength for some frequency slightly below 10 MHz. (Have I got this right?) The coax would travel approx. 4 meters to my window, where it would go through another matching transformer and into the external antenna input of the radio. Wouldn't that be a half-wave dipole? A folded dipole is made from twinlead by first cutting it to a half wavelength long (total length) for the frequency you want. The two wires in each end are connected together. Then you open (strip) an inch or so of the insulation for one wire *only* (either wire), at the middle of the twinlead. Cut the exposed wire and pull two short lengths of it (pigtails) out of the twinlead. Connect each of those wires to the matching transformer on it's high impedance side. Would it matter that the side of the house is covered in steel siding, against which it would be lying? Yes it would. You want to get the twinlead section out in the open, like between two trees, and as high as possible. The coax would run from the middle of the twinlead dipole (matching transformer) to the receiver. The dipole should be orientated so it runs at a right angle to the two directions you want to hear the best. If you wanted to hear signals from the east and west, you would run the dipole (twinlead) north to south. Would this work, or would an inverted L still be better (or quieter)? I could put the grounding rod immediately outside my window, which might enable me to make the long leg of the L somewhat longer than the combined 30 meters of the dipole. That would make for a shorter run of coax, but the soil would be drier thereby making for a poorer ground (where it is now, the grounding rod sits next to the output of a downspout.) It's not clear to me why you are thinking of making a folded dipole when a simple dipole would be easier. The latter doesn't require any matching transformer for the coax and uses just one wire (split in the middle) for the dipole element. A dipole responds best to the frequency for which it is designed and it's bi-directional. The inverted-L is a broadband antenna and usually non-directional if it's not too long. I suggest you build a low noise inverted-L. See the following website: http://www.anarc.org/naswa/badx/ante...e_antenna.html If I went with the inverted L (with joined conducters on the far end to make a loop) would I still ground one side of the twin-lead? Do you ground one side of a loop? If you join the ends, you no longer have an inverted-L design. It's become a horizontal loop antenna. You wouldn't use twinlead to make an inverted-L, just a single horizontal wire with either a single lead wire from one end or coax. The website I gave you (above) shows the best way to connect a coax lead to an inverted-L. Okay, I've written War and Peace. Sorry for the great number of questions, I'm just trying to understand the fundamentals of installing an antenna. I hope I am not trying your patience. Thanks, Dave No problem with the questions. It's nice to see an interesting on topic thread for a change. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Hey Starman,
Thanks for the answers. Following are replies interspersed. "starman" wrote in message ... Dave wrote: Okay, I'll try to keep you posted. Here's what I asked on Yahoo! OKAY, here are the new questions and clarifications... Thanks for clearing up for me why it is called a random wire. I thought that was just what they called it when it wasn't 1/4 or 1/2 wavelength. I realized something today- I think I am actually talking about installing a HALF-WAVE dipole, not a 1/4 wave. Since it is twin-lead I am talking about, and since it is going to be joined at the far end, each leg would be twice the 1/4 wavelength of the physical cable. Am I right here? It sounds like you're thinking about making a folded dipole. The total length of the twinlead folded dipole should still be a half wavelength but the impedance at the connection point (middle) for the downlead changes from about 50-ohms for a simple dipole to 300-ohms for the folded type. This means a 50 or 75-ohm coax lead would not be suitable without a 6:1 impedance matching transformer. The higher impedance side of the transformer connects to the middle of the dipole and the low side goes to the coax. Yes, I saw a diagram of a folded dipole today in an old Amateur Radio Handbook, and it looks like what I am talking about, more or less. I also found out that a half-wave dipole does not need to be grounded. Correct me if I am wrong, but you do ground one side of a dipole, right? So one leg would be grounded along with the shield of the coax, right? It's not necessary to ground the coax shield from a dipole because it's a balanced antenna design. However you may want to ground the chassis of the receiver itself. The coax should be connnected to a balanced antenna input on the receiver. This means the coax shield is not directly connected (grounded) to the receiver's chassis. You should be aware that some receiver's don't have the proper input connection for a balanced antenna like a dipole. In that case you would just connect the coax to whatever external antenna input there is and not be concerned whether the coax shield is grounded to the chassis or not. It's not the ideal way to do it, but sometimes you don't have any choice. I forgot what receiver you're using. I am using a DX-402 (aka Sangean ATS 505). I would be surprised if it had a balanced antenna input, and have been thinking about just clipping the external antenna to my whip after all. I hooked 20 feet of 300 ohm twinlead to a 300/75 ohm transformer and miniplug last night and plugged it in, but the signal strength was about half of what my whip gives me. Therefore, the change in plans. What I am visualizing is two pieces of twin-lead, one called A (left) and the other called B (right.) A would have one side of one end soldered to the ground rod (call this the "near" end) with the other side of that end hanging out in space. The rest of that piece of twin-lead (side A) would go up the side of my house to the eaves and over several meters. The far end of A would have the two conductors soldered together. B would have one side of the "near" end attached to the appropriate lead of a 300/75 ohm matching transformer, which has it's other lead soldered to the grounding rod and goes to 75 ohm coax. The other side of the "near" end of B hangs out in space. B would then go up the side of the house to the eaves, just like A, but would then stretch several meters in the other direction. The "far" end of B would also have the two conductors soldered together. Each leg is a little over 15 meters long (counting the part that goes up as well as the part that goes over), which would make the whole dipole a half-wavelength for some frequency slightly below 10 MHz. (Have I got this right?) The coax would travel approx. 4 meters to my window, where it would go through another matching transformer and into the external antenna input of the radio. Wouldn't that be a half-wave dipole? A folded dipole is made from twinlead by first cutting it to a half wavelength long (total length) for the frequency you want. The two wires in each end are connected together. Then you open (strip) an inch or so of the insulation for one wire *only* (either wire), at the middle of the twinlead. Cut the exposed wire and pull two short lengths of it (pigtails) out of the twinlead. Connect each of those wires to the matching transformer on it's high impedance side. Gotcha. Saw a diagram like that today in that book, so I understand what you are talking about. This would be easy. Would it matter that the side of the house is covered in steel siding, against which it would be lying? Yes it would. You want to get the twinlead section out in the open, like between two trees, and as high as possible. The coax would run from the middle of the twinlead dipole (matching transformer) to the receiver. The dipole should be orientated so it runs at a right angle to the two directions you want to hear the best. If you wanted to hear signals from the east and west, you would run the dipole (twinlead) north to south. Gotcha. I was planning on running the vertical portion of twinlead that went from ground level/grounding rod/coax up to the eaves over the steel siding, but I could just as easily run the coax up the side of the house, which would put all of the twinlead above the steel siding. Still not "out in the open" but probably the best I can do. Wifey doesn't want anything that obviously says "Hi there, I'm an antenna!" I am beginning to consider running the coax around to the end of the house and up that side, and laying the twinlead along the ridge of the roof from one end to the other. That would be a up a lot higher and a lot more "out in the open." Would this work, or would an inverted L still be better (or quieter)? I could put the grounding rod immediately outside my window, which might enable me to make the long leg of the L somewhat longer than the combined 30 meters of the dipole. That would make for a shorter run of coax, but the soil would be drier thereby making for a poorer ground (where it is now, the grounding rod sits next to the output of a downspout.) It's not clear to me why you are thinking of making a folded dipole when a simple dipole would be easier. The latter doesn't require any matching transformer for the coax and uses just one wire (split in the middle) for the dipole element. A dipole responds best to the frequency for which it is designed and it's bi-directional. The inverted-L is a broadband antenna and usually non-directional if it's not too long. I suggest you build a low noise inverted-L. See the following website: http://www.anarc.org/naswa/badx/ante...e_antenna.html I will check this out. I was thinking of a folded dipole just because I already have 50' of twinlead sitting around. Of course, I have plenty of regular wire sitting around too. If I went with the inverted L (with joined conducters on the far end to make a loop) would I still ground one side of the twin-lead? Do you ground one side of a loop? If you join the ends, you no longer have an inverted-L design. It's become a horizontal loop antenna. You wouldn't use twinlead to make an inverted-L, just a single horizontal wire with either a single lead wire from one end or coax. The website I gave you (above) shows the best way to connect a coax lead to an inverted-L. Gotcha. I'll look at it and sleep on it. Okay, I've written War and Peace. Sorry for the great number of questions, I'm just trying to understand the fundamentals of installing an antenna. I hope I am not trying your patience. Thanks, Dave No problem with the questions. It's nice to see an interesting on topic thread for a change. Thanks for the encouragement. I'm not yet sure what I will end up doing, but I want to make the best decision possible. Dave |
Dave wrote:
I am using a DX-402 (aka Sangean ATS 505). I would be surprised if it had a balanced antenna input, and have been thinking about just clipping the external antenna to my whip after all. I hooked 20 feet of 300 ohm twinlead to a 300/75 ohm transformer and miniplug last night and plugged it in, but the signal strength was about half of what my whip gives me. Therefore, the change in plans. It would be a mistake to connect a good external antenna directly to the whip. The receiver will almost certainly overload. You know the symptoms for overloading now. If you build the low noise inverted-L, the coax can be connected to the external antenna jack with a mini plug. I was planning on running the vertical portion of twinlead that went from ground level/grounding rod/coax up to the eaves over the steel siding, but I could just as easily run the coax up the side of the house, which would put all of the twinlead above the steel siding. Still not "out in the open" but probably the best I can do. Wifey doesn't want anything that obviously says "Hi there, I'm an antenna!" It's funny how women have an aversion to antennas. Must be an esthetic thing. :-) I am beginning to consider running the coax around to the end of the house and up that side, and laying the twinlead along the ridge of the roof from one end to the other. That would be a up a lot higher and a lot more "out in the open." The horizontal section (single wire) of an inverted-L could also run along the roof ridge. The vertical downlead wire would connect to one end of the horizontal section and run down the end wall of the house to the ground. The balun would be located near the ground next to a ground rod. The coax would go from the balun to the receiver. That's the design of the low noise inverted-L except it's better to locate the antenna away from the house when you can. No problem with the questions. It's nice to see an interesting on topic thread for a change. Thanks for the encouragement. I'm not yet sure what I will end up doing, but I want to make the best decision possible. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Replies interspersed.
"starman" wrote in message ... Dave wrote: I am using a DX-402 (aka Sangean ATS 505). I would be surprised if it had a balanced antenna input, and have been thinking about just clipping the external antenna to my whip after all. I hooked 20 feet of 300 ohm twinlead to a 300/75 ohm transformer and miniplug last night and plugged it in, but the signal strength was about half of what my whip gives me. Therefore, the change in plans. It would be a mistake to connect a good external antenna directly to the whip. The receiver will almost certainly overload. You know the symptoms for overloading now. If you build the low noise inverted-L, the coax can be connected to the external antenna jack with a mini plug. If it wasn't much worse than what I am dealing with right now, I can live with it. Especially if I buy or build an antenna tuner, which I am planning to add in one way or another. Let me ask you this, what makes the inverted L so good for noise? I am taking what you say seriously, but if I install the antenna on top of the roof and run it down the other side of the house it will be quite close to our A/C compressor, which I expect to become a significant source of EMI. What if I just ran it along the ridge of the house and attached it to coax up *there*, before running the coax down the side of the house and grounding the shield to the grounding rod? Seems like that would eliminate a great deal of EMI from the A/C compressor, which I cannot move. I was planning on running the vertical portion of twinlead that went from ground level/grounding rod/coax up to the eaves over the steel siding, but I could just as easily run the coax up the side of the house, which would put all of the twinlead above the steel siding. Still not "out in the open" but probably the best I can do. Wifey doesn't want anything that obviously says "Hi there, I'm an antenna!" It's funny how women have an aversion to antennas. Must be an esthetic thing. :-) Wife read your comments and laughed. She says that if women designed antennas they would be a lot prettier. Probably Modern Art, if I know her. :) I am beginning to consider running the coax around to the end of the house and up that side, and laying the twinlead along the ridge of the roof from one end to the other. That would be a up a lot higher and a lot more "out in the open." The horizontal section (single wire) of an inverted-L could also run along the roof ridge. The vertical downlead wire would connect to one end of the horizontal section and run down the end wall of the house to the ground. The balun would be located near the ground next to a ground rod. The coax would go from the balun to the receiver. That's the design of the low noise inverted-L except it's better to locate the antenna away from the house when you can. Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) No problem with the questions. It's nice to see an interesting on topic thread for a change. Thanks for the encouragement. I'm not yet sure what I will end up doing, but I want to make the best decision possible. Gotta go. Wife has to get up at 5:00 and I am supposed to get up first and fix breakfast. Long day tomorrow. I pulled up the grounding rod today (using a car jack to lift it out) and then told my wife what I had done. She asked what it was there for, and why didn't we still need it. Told her the TV antenna used to be connected to it, but since we moved that it wasn't being used. Now I need to install another grounding rod for the TV antenna in it's new location. Wasn't thinking when I put it there and didn't ground it. It's not hooked up anyway. We haven't even watched any broadcast programs on that TV in years, using the small one with an independant antenna in the bedroom instead. The big one is just used for watching DVD's. Thanks for the help. Dave |
The word balun to describe this device, while quite common, is incorrect. Go
he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) |
It's an impedance matching transformer or unun. I use the word 'balun'
because most people haven't heard the term 'unun'. CW wrote: The word balun to describe this device, while quite common, is incorrect. Go he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
We knew that you knew the difference. :) I was just insuring that Dave new
the difference. "starman" wrote in message ... It's an impedance matching transformer or unun. I use the word 'balun' because most people haven't heard the term 'unun'. CW wrote: The word balun to describe this device, while quite common, is incorrect. Go he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
starman wrote in message ...
Dave wrote: I am using a DX-402 (aka Sangean ATS 505). I would be surprised if it had a balanced antenna input, and have been thinking about just clipping the external antenna to my whip after all. I hooked 20 feet of 300 ohm twinlead to a 300/75 ohm transformer and miniplug last night and plugged it in, but the signal strength was about half of what my whip gives me. Therefore, the change in plans. It would be a mistake to connect a good external antenna directly to the whip. The receiver will almost certainly overload. You know the symptoms for overloading now. If you build the low noise inverted-L, the coax can be connected to the external antenna jack with a mini plug. I was planning on running the vertical portion of twinlead that went from ground level/grounding rod/coax up to the eaves over the steel siding, but I could just as easily run the coax up the side of the house, which would put all of the twinlead above the steel siding. Still not "out in the open" but probably the best I can do. Wifey doesn't want anything that obviously says "Hi there, I'm an antenna!" It's funny how women have an aversion to antennas. Must be an esthetic thing. :-) I am beginning to consider running the coax around to the end of the house and up that side, and laying the twinlead along the ridge of the roof from one end to the other. That would be a up a lot higher and a lot more "out in the open." DAVE & STARMAN, - - - - - - - - - - This would be my recommendation - - - - - - - - - - The horizontal section (single wire) of an inverted-L could also run along the roof ridge. The vertical downlead wire would connect to one end of the horizontal section and run down the end wall of the house to the ground. The balun would be located near the ground next to a ground rod. The coax would go from the balun to the receiver. That's the design of the low noise inverted-L except it's better to locate the antenna away from the house when you can. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Unless you have a Target Frequency and Country (Direction) I do not recommend Dipole Antennas for general all around broadband 500kHz to 30MHz Shortwave Listener "SWL" Antennas. iane ~ RHF No problem with the questions. It's nice to see an interesting on topic thread for a change. Thanks for the encouragement. I'm not yet sure what I will end up doing, but I want to make the best decision possible. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
THANK YOU for this link! I especially like the schematic for the MFJ-956.
I'm definetly going to build that. Dave "CW" wrote in message ... The word balun to describe this device, while quite common, is incorrect. Go he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) |
So, a matching transformer is all I need? I have pretty much decided to use
300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer to connect it to the coax, and more as needed between the coax and radio. Will that honestly work? Thanks, Dave "starman" wrote in message ... It's an impedance matching transformer or unun. I use the word 'balun' because most people haven't heard the term 'unun'. CW wrote: The word balun to describe this device, while quite common, is incorrect. Go he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
I *think* I do. I'll definetly read more on the subject though. :)
Dave "CW" wrote in message ... We knew that you knew the difference. :) I was just insuring that Dave new the difference. "starman" wrote in message ... It's an impedance matching transformer or unun. I use the word 'balun' because most people haven't heard the term 'unun'. CW wrote: The word balun to describe this device, while quite common, is incorrect. Go he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"RHF" wrote in message m... starman wrote in message ... Dave wrote: I am using a DX-402 (aka Sangean ATS 505). I would be surprised if it had a balanced antenna input, and have been thinking about just clipping the external antenna to my whip after all. I hooked 20 feet of 300 ohm twinlead to a 300/75 ohm transformer and miniplug last night and plugged it in, but the signal strength was about half of what my whip gives me. Therefore, the change in plans. It would be a mistake to connect a good external antenna directly to the whip. The receiver will almost certainly overload. You know the symptoms for overloading now. If you build the low noise inverted-L, the coax can be connected to the external antenna jack with a mini plug. I was planning on running the vertical portion of twinlead that went from ground level/grounding rod/coax up to the eaves over the steel siding, but I could just as easily run the coax up the side of the house, which would put all of the twinlead above the steel siding. Still not "out in the open" but probably the best I can do. Wifey doesn't want anything that obviously says "Hi there, I'm an antenna!" It's funny how women have an aversion to antennas. Must be an esthetic thing. :-) I am beginning to consider running the coax around to the end of the house and up that side, and laying the twinlead along the ridge of the roof from one end to the other. That would be a up a lot higher and a lot more "out in the open." DAVE & STARMAN, - - - - - - - - - - This would be my recommendation - - - - - - - - - - The horizontal section (single wire) of an inverted-L could also run along the roof ridge. The vertical downlead wire would connect to one end of the horizontal section and run down the end wall of the house to the ground. The balun would be located near the ground next to a ground rod. The coax would go from the balun to the receiver. That's the design of the low noise inverted-L except it's better to locate the antenna away from the house when you can. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Unless you have a Target Frequency and Country (Direction) I do not recommend Dipole Antennas for general all around broadband 500kHz to 30MHz Shortwave Listener "SWL" Antennas. iane ~ RHF Gotcha. Thanks for that clarification. I do appreciate it. Dave No problem with the questions. It's nice to see an interesting on topic thread for a change. Thanks for the encouragement. I'm not yet sure what I will end up doing, but I want to make the best decision possible. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Forgot to mention, I was going to connect the conductors on the far end so
as to have a longer single line. One side of the near end would be hanging out in space, in other words, so as not to form a loop. Dave "Dave" wrote in message ... So, a matching transformer is all I need? I have pretty much decided to use 300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer to connect it to the coax, and more as needed between the coax and radio. Will that honestly work? Thanks, Dave "starman" wrote in message ... It's an impedance matching transformer or unun. I use the word 'balun' because most people haven't heard the term 'unun'. CW wrote: The word balun to describe this device, while quite common, is incorrect. Go he www.kc7nod.20m.com Look for matching transformer. "Dave" wrote in message ... Away from the house is not possible. Even if it was, that would put it near the power lines. How would I build a balun? (Websites/links?) -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Dave wrote:
So, a matching transformer is all I need? I have pretty much decided to use 300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer to connect it to the coax, and more as needed between the coax and radio. Will that honestly work? Thanks, Dave A 300/50 ohm transformer is the most common type for a shortwave folded dipole. You can still use 75-ohm coax to the 50-ohm side of the transformer. There would be a slight impedance mismatch but it's not that important for a receiving antenna. I do not recommend using a 300/75 TV balun for this purpose because it's designed to operate at much higher frequencies than shortwave. Remember that you *must* connect the two wires in the ends of the twinlead together to make a folded dipole. Otherwise the high impedance side of the matching transformer (300-ohms) won't be the right value for the antenna. Finally, don't expect this antenna to be great for all shortwave frequencies and directions. We discussed why this is so in an earlier exchange. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
STARMAN,
Why Use a TV type 300 to 75 Ohm Matching Transformer with your SWL Antenna and 'portable AM/FM/Shortwave Radio. May I interject my opinion based on some simple observations using both SWL/HAM Matching Transformers and the cheap TV type 300 to 75 Ohm Matching Transformers. ABOUT - The TV type 300 to 75 Ohm Matching Transformers a * Easy to Find. {RadioShack, WalMart, Walgreens, Kragens, etc} * Simple to Use. {How To - Hook-Em-Up is Self-Evident} * Low Cost. {Under $5} * Generally Functions well and Operates down to 5 MHz and well above 30 MHz. (Most of the better quality ones are now "Marked" for 5 MHz and up.) * Provides Coverage of 'most' of the International Shortwave Bands: 60M, 49M, 41M, 31M, 25M, 21M, 19M, 16M, 13M, and 11M. (But not 90M and 75M Bands) * Plus 'helps' to "Attenuate" Strong AM/MW Signals that create images in the Shortwave Bands. {This is an Important Bonus.} * Allows the 'direct' Connection "Hook-Up" of Low Cost 75 Ohm TV type Coax Cable as an antenna Lead-in-Line. IMHO: For most/many 'portable' AM/FM/Shortwave Radios using a TV type 300 to 75 Ohm Matching Transformer is a very good alternative to a SWL/HAM Matching Transformer. [ Value and Cost ] iane ~ RHF .. .. = = = starman wrote in message = = = ... Dave wrote: So, a matching transformer is all I need? I have pretty much decided to use 300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer to connect it to the coax, and more as needed between the coax and radio. Will that honestly work? Thanks, Dave A 300/50 ohm transformer is the most common type for a shortwave folded dipole. You can still use 75-ohm coax to the 50-ohm side of the transformer. There would be a slight impedance mismatch but it's not that important for a receiving antenna. I do not recommend using a 300/75 TV balun for this purpose because it's designed to operate at much higher frequencies than shortwave. Remember that you *must* connect the two wires in the ends of the twinlead together to make a folded dipole. Otherwise the high impedance side of the matching transformer (300-ohms) won't be the right value for the antenna. Finally, don't expect this antenna to be great for all shortwave frequencies and directions. We discussed why this is so in an earlier exchange. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Starman,
I am no longer intending to use a folded dipole, or a dipole of any kind. I am currently planning to connect the conductors at the far end of the 300 ohm twinlead but only connect one side of the near end to the 300/75 ohm matching transformer. Will this not work? I don't need perfection, just reasonably good (I think.) Thanks, Dave "starman" wrote in message ... Dave wrote: So, a matching transformer is all I need? I have pretty much decided to use 300 ohm twinlead along the rood ridge with a 300/75 ohm matching transformer to connect it to the coax, and more as needed between the coax and radio. Will that honestly work? Thanks, Dave A 300/50 ohm transformer is the most common type for a shortwave folded dipole. You can still use 75-ohm coax to the 50-ohm side of the transformer. There would be a slight impedance mismatch but it's not that important for a receiving antenna. I do not recommend using a 300/75 TV balun for this purpose because it's designed to operate at much higher frequencies than shortwave. Remember that you *must* connect the two wires in the ends of the twinlead together to make a folded dipole. Otherwise the high impedance side of the matching transformer (300-ohms) won't be the right value for the antenna. Finally, don't expect this antenna to be great for all shortwave frequencies and directions. We discussed why this is so in an earlier exchange. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Dave wrote:
Starman, I am no longer intending to use a folded dipole, or a dipole of any kind. I am currently planning to connect the conductors at the far end of the 300 ohm twinlead but only connect one side of the near end to the 300/75 ohm matching transformer. Will this not work? I don't need perfection, just reasonably good (I think.) Thanks, Dave So you're going to use the twinlead as if it was a single wire. In that case, you might as well connect the two wires in the near end too. There isn't any advantage to keeping the wires of the near end seperated. Connect the twinlead's near end to one wire of the high impedance side (300-ohm) of the matching transformer (balun). The other wire on the 300-ohm side should go to a ground rod, IF you're building the antenna design on the website I gave you. Otherwise connect the remaining 300-ohm wire to the shield of the coax. This will require some kind of adapter, if the balun has a threaded female F-connector for the coax on the low impedance side. A standard coax inline grounding adapter (block) would work. These are made for connecting a ground wire to the coax shield in a TV installation. This adapter has a female F-connector on each end and a grounding screw on the outside of the 'block'. Connect the remaining wire on the 300-ohm side to the ground screw on the adapter block. If you use this kind of adapter you will also need another adapter with a male F-connector on each end to connect the ground adapter block to the threaded female side of the balun. You might be able to find a coax grounding adapter which has a male F-connector on one end and a female on the other end, along with the grounding terminal. Then you wouldn't need two adapters. The center wire of the coax goes to the low impedance side of the balun which is the center hole of the threaded female F-connector on the balun. The coax shield connects to the outside threads of that F-connector, which would also go to the ground rod from the grounding adapter, if you're making the website antenna. All of the above assumes you're using a standard TV balun which has a threaded female coax F-connector for the low impedance side and two wires (pigtails) on the high side. You should install a male F-connector on the balun end of the coax. In the previous post I advised against using a TV balun because it will most likely attenuate signals below about 10-Mhz. This means the lower shortwave bands and also the regular AM(MW) band would be somewhat weaker but this might not be a problem, depending on what frequencies/bands you want to hear best. -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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