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type/length of wire and connectors for external antenna?
I'd like to try an external antenna, but one was not included with my
G5. What type of wire should I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim |
type/length of wire and connectors for external antenna?
On Oct 2, 11:13*am, JimK wrote:
- I'd like to try an external antenna, but one was not included with my - G5. What type of wire should I get (stranded, solid, gauge, - insulated...), and do I just solder it to the pos or neg lead of a - miniplug to go into the ext antenna receptacle? - - Thanks.... - - Jim JimK, For 'small' potable Radios, consider the "Portable Wire Antenna" http://groups.google.com/group/rec.r...c03868d10d3d23 Note the "PWA" that was created and written about -by- Tom Sevart [N2UHC] Portable Wire Antenna "PWA" for the Sony ICF-2010. To 'quote' Tom Sevant "This is an antenna I put together after having problems with overload on my Sony 2010 portable shortwave receiver" GoTo= http://www.geocities.com/n2uhc/portablewire.html |
type/length of wire and connectors for external antenna?
On Oct 3, 4:43*am, "~ RHF" wrote:
On Oct 2, 11:13*am, JimK wrote: - I'd like to try an external antenna, but one was not included with my - G5. What type of wire should I get (stranded, solid, gauge, - insulated...), and do I just solder it to the pos or neg lead of a - miniplug to go into the ext antenna receptacle? - - Thanks.... - - Jim JimK, For 'small' potable Radios, consider the "Portable Wire Antenna"http://groups.google.com/group/rec.radio.shortwave/msg/eec03868d10d3d23 Note the "PWA" that was created and written about -by- Tom Sevart [N2UHC] Portable Wire Antenna "PWA" for the Sony ICF-2010. To 'quote' Tom Sevant "This is an antenna I put together after having problems with overload on my Sony 2010 portable shortwave receiver" GoTo=http://www.geocities.com/n2uhc/portablewire.html *. Using the "Portable Wire Antenna" (PWA) with your 'portable' AM/FM Shortwave Radiohttp://groups.google.com/group/rec.radio.shortwave/msg/a789c8fd6fcb38f2 *. Two Things that most 'portable' AM/FM Shortwave Radios Could Use for "Improved" Shortwave Radio Listening (SWL)http://groups.google.com/group/rec.r...3b6d9bcdb872a8 *. Tune-A-Stick -and- Portable Wire Antenna (PWA) for Whip Antenna Couplers to External Shortwave Listener (SWL) Antennashttp://groups.google.com/group/rec.radio.shortwave/msg/09c73c4c94625fc7 *. AM/MW DXing Antenna : Your Radio + Lazy Susan + AM/MW Loop Antenna for better AM/MW Band Reception and DXing with a 'portable AM/FM Shortwave Radiohttp://groups.google.com/group/rec.radio..shortwave/msg/ef0d07ba9f706b1b *. iane ~ RHF *. Thank you very much once again, RHF, for your kind and comprehensive help. And again, you have given me some work to do :-). |
type/length of wire and connectors for external antenna?
http://groups.yahoo.com/group/EtonE5/files/
Here you will find an "inductive coupler for whips" project complete with pictures that does work well. It completely isolates the whip from the external antenna while at the same time providing coupling between the two. A torroid version of the project is also given. "JimK" wrote in message ... On Oct 3, 4:43 am, "~ RHF" wrote: On Oct 2, 11:13 am, JimK wrote: - I'd like to try an external antenna, but one was not included with my - G5. What type of wire should I get (stranded, solid, gauge, - insulated...), and do I just solder it to the pos or neg lead of a - miniplug to go into the ext antenna receptacle? - - Thanks.... - - Jim JimK, For 'small' potable Radios, consider the "Portable Wire Antenna"http://groups.google.com/group/rec.radio.shortwave/msg/eec03868d10d3d23 Note the "PWA" that was created and written about -by- Tom Sevart [N2UHC] Portable Wire Antenna "PWA" for the Sony ICF-2010. To 'quote' Tom Sevant "This is an antenna I put together after having problems with overload on my Sony 2010 portable shortwave receiver" GoTo=http://www.geocities.com/n2uhc/portablewire.html . Using the "Portable Wire Antenna" (PWA) with your 'portable' AM/FM Shortwave Radiohttp://groups.google.com/group/rec.radio.shortwave/msg/a789c8fd6fcb38f2 . Two Things that most 'portable' AM/FM Shortwave Radios Could Use for "Improved" Shortwave Radio Listening (SWL)http://groups.google.com/group/rec.r...3b6d9bcdb872a8 . Tune-A-Stick -and- Portable Wire Antenna (PWA) for Whip Antenna Couplers to External Shortwave Listener (SWL) Antennashttp://groups.google.com/group/rec.radio.shortwave/msg/09c73c4c94625fc7 . AM/MW DXing Antenna : Your Radio + Lazy Susan + AM/MW Loop Antenna for better AM/MW Band Reception and DXing with a 'portable AM/FM Shortwave Radiohttp://groups.google.com/group/rec.radio.shortwave/msg/ef0d07ba9f706b1b . iane ~ RHF . Thank you very much once again, RHF, for your kind and comprehensive help. And again, you have given me some work to do :-). |
type/length of wire and connectors for external antenna?
On 2 oct, 20:13, JimK wrote:
I'd like to try an external antenna, but one was not included with my G5. What type of wire should I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metal wire will work for you situation (solid, stranded, plasticized galvanized washing line, etc). Most modern SW receivers with internal antennas are very sensitive, but cannot handle strong signals, so longer will not always be better. To reduce the interference from electronic equipment close to your SW receiver, you may put a coaxial cable between the actual antenna and the receiver. You can use any type of 75, 90 or 50 Ohms cable. The center conductor goes to the center pin of the mini plug and the bread goes to the ground of the mini plug. The antenna side of the cable needs some clarification. The antenna wire goes to the center conductor of the cable, the braid should be connected to ground outside your house (or at least far away from where you expect or have interference). What is "ground"? When you live in an apartment, it can be the metal fence or railing of the balcony. You can use a ground rod or any other large metallic structure outside your house. Connect the braid of the cable directly to the ground structure. Do not insert a long run of wire between the metal structure and the braid of the coaxial cable. For some form of static / impulse protection you may add a 1 3 uH inductor between the center conductor and the braid. Note that this inductor will attenuate AM broadcast band reception. As others said, you have to experiment with the orientation of the wire to get best signal/noise ratio. When you are very limited in space for the wire, you may use some 5..10 feet of chicken mesh as reception antenna or use more wires in a fan shape. Best regards, Wim PA3DJS www.tetech.nl please remove abc when using PM. |
type/length of wire and connectors for external antenna?
Wimpie wrote:
On 2 oct, 20:13, JimK wrote: I'd like to try an external antenna, but one was not included with my G5. What type of wire should I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metal wire will work for you situation (solid, stranded, plasticized galvanized washing line, etc). Most modern SW receivers with internal antennas are very sensitive, but cannot handle strong signals, so longer will not always be better. To reduce the interference from electronic equipment close to your SW receiver, you may put a coaxial cable between the actual antenna and the receiver. You can use any type of 75, 90 or 50 Ohms cable. The center conductor goes to the center pin of the mini plug and the bread goes to the ground of the mini plug. The antenna side of the cable needs some clarification. The antenna wire goes to the center conductor of the cable, the braid should be connected to ground outside your house (or at least far away from where you expect or have interference). What is "ground"? When you live in an apartment, it can be the metal fence or railing of the balcony. You can use a ground rod or any other large metallic structure outside your house. Connect the braid of the cable directly to the ground structure. Do not insert a long run of wire between the metal structure and the braid of the coaxial cable. For some form of static / impulse protection you may add a 1 3 uH inductor between the center conductor and the braid. Note that this inductor will attenuate AM broadcast band reception. As others said, you have to experiment with the orientation of the wire to get best signal/noise ratio. When you are very limited in space for the wire, you may use some 5..10 feet of chicken mesh as reception antenna or use more wires in a fan shape. Best regards, Wim PA3DJS www.tetech.nl please remove abc when using PM. A couple clip leads on the whip helps sometimes. If you want to use a real antenna, you need a real radio. http://en.wikipedia.org/wiki/Communications_receiver |
type/length of wire and connectors for external antenna?
"dave" wrote in message ... Wimpie wrote: On 2 oct, 20:13, JimK wrote: I'd like to try an external antenna, but one was not included with my G5. What type of wire should I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metal wire will work for you situation (solid, stranded, plasticized galvanized washing line, etc). Most modern SW receivers with internal antennas are very sensitive, but cannot handle strong signals, so longer will not always be better. To reduce the interference from electronic equipment close to your SW receiver, you may put a coaxial cable between the actual antenna and the receiver. You can use any type of 75, 90 or 50 Ohms cable. The center conductor goes to the center pin of the mini plug and the bread goes to the ground of the mini plug. The antenna side of the cable needs some clarification. The antenna wire goes to the center conductor of the cable, the braid should be connected to ground outside your house (or at least far away from where you expect or have interference). What is "ground"? When you live in an apartment, it can be the metal fence or railing of the balcony. You can use a ground rod or any other large metallic structure outside your house. Connect the braid of the cable directly to the ground structure. Do not insert a long run of wire between the metal structure and the braid of the coaxial cable. For some form of static / impulse protection you may add a 1 3 uH inductor between the center conductor and the braid. Note that this inductor will attenuate AM broadcast band reception. As others said, you have to experiment with the orientation of the wire to get best signal/noise ratio. When you are very limited in space for the wire, you may use some 5..10 feet of chicken mesh as reception antenna or use more wires in a fan shape. Best regards, Wim PA3DJS www.tetech.nl please remove abc when using PM. A couple clip leads on the whip helps sometimes. If you want to use a real antenna, you need a real radio. http://en.wikipedia.org/wiki/Communications_receiver That brought back some memories ! bmc |
type/length of wire and connectors for external antenna?
"Brian Colwell" wrote in message ... "dave" wrote in message ... Wimpie wrote: On 2 oct, 20:13, JimK wrote: I'd like to try an external antenna, but one was not included with my G5. What type of wire should I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metal wire will work for you situation (solid, stranded, plasticized galvanized washing line, etc). Snip http://en.wikipedia.org/wiki/Communications_receiver That brought back some memories ! bmc The best one I ever had was a Thordarson Meissner, can't remember the model. The one I always wanted, was a Hammarlund Super Pro. Now that was a radio! Steve R. |
type/length of wire and connectors for external antenna?
"Steve R." wrote in message ... "Brian Colwell" wrote in message ... "dave" wrote in message ... Wimpie wrote: On 2 oct, 20:13, JimK wrote: I'd like to try an external antenna, but one was not included with my G5. What type of wire should I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metal wire will work for you situation (solid, stranded, plasticized galvanized washing line, etc). Snip http://en.wikipedia.org/wiki/Communications_receiver That brought back some memories ! bmc The best one I ever had was a Thordarson Meissner, can't remember the model. The one I always wanted, was a Hammarlund Super Pro. Now that was a radio! Steve R. My first receiver was an ex airforce model R1155...there was an outfit that got hold of some surplus units and modified the power supply.....it was a pretty good performer.....we had little choice, at that time !! But you are so right about the Super Pro. bmc |
type/length of wire and connectors for external antenna?
On Oct 4, 4:15*am, Wimpie wrote:
On 2 oct, wrote: I'd like to try an external antenna, but one was not included with my G5. What type ofwireshould I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metalwirewill work for you situation (solid, stranded, plasticized galvanized washing line, etc). Most modern SW receivers with internal antennas are very sensitive, but cannot handle strong signals, so longer will not always be better. To reduce the interference from electronic equipment close to your SW receiver, you may put a coaxial cable between the actual antenna and the receiver. You can use any type of 75, 90 or 50 Ohms cable. The center conductor goes to the center pin of the mini plug and the bread goes to the ground of the mini plug. The antenna side of the cable needs some clarification. The antennawiregoes to the center conductor of the cable, the braid should be connected to ground outside your house (or at least far away from where you expect or have interference). What is "ground"? *When you live in an apartment, it can be the metal fence or railing of the balcony. *You can use a ground rod or any other large metallic structure outside your house. Connect the braid of the cable directly to the ground structure. Do not insert a long run ofwirebetween the metal structure and the braid of the coaxial cable. For some form of static / impulse protection you may add a 1 3 uH inductor between the center conductor and the braid. Note that this inductor will attenuate AM broadcast band reception. As others said, you have to experiment with the orientation of thewireto get best signal/noise ratio. When you are very limited in space for thewire, you may use some 5..10 feet of chicken mesh as reception antenna or use more wires in a fan shape. Best regards, Wim PA3DJSwww.tetech.nl please remove abc when using PM. Hi Wim, I've been reading the linnks kindly provided in this thread. Am I correct that a wire antenna can actually damage my radio? Does using an inductive coil around the whip completely eliminate this possibility? I'd like to take advantage of the antenna out on the G5. Is there not safe way? Also, if I connect the shield braid of a coax to the ground without intervening run of wire, then there will need to be a run of wire from the center coax lead to the radio. Is this OK? Thanks all. |
type/length of wire and connectors for external antenna?
On Oct 4, 4:15*am, Wimpie wrote:
On 2 oct, wrote: I'd like to try an external antenna, but one was not included with my G5. What type ofwireshould I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metalwirewill work for you situation (solid, stranded, plasticized galvanized washing line, etc). Most modern SW receivers with internal antennas are very sensitive, but cannot handle strong signals, so longer will not always be better. To reduce the interference from electronic equipment close to your SW receiver, you may put a coaxial cable between the actual antenna and the receiver. You can use any type of 75, 90 or 50 Ohms cable. The center conductor goes to the center pin of the mini plug and the bread goes to the ground of the mini plug. The antenna side of the cable needs some clarification. The antennawiregoes to the center conductor of the cable, the braid should be connected to ground outside your house (or at least far away from where you expect or have interference). What is "ground"? *When you live in an apartment, it can be the metal fence or railing of the balcony. *You can use a ground rod or any other large metallic structure outside your house. Connect the braid of the cable directly to the ground structure. Do not insert a long run ofwirebetween the metal structure and the braid of the coaxial cable. For some form of static / impulse protection you may add a 1 3 uH inductor between the center conductor and the braid. Note that this inductor will attenuate AM broadcast band reception. As others said, you have to experiment with the orientation of thewireto get best signal/noise ratio. When you are very limited in space for thewire, you may use some 5..10 feet of chicken mesh as reception antenna or use more wires in a fan shape. Best regards, Wim PA3DJSwww.tetech.nl please remove abc when using PM. OK, sorry, I see I was confusing the antenna and radio sides of the coax. The radio side: center of coax to center of mini, shield brain to surround of mini. Antenna side: braid to ground post, center to antenna wire. So I can have the run between outside ground post and radio using coax. But can I damage G5 with an external wire? If so I'll use the whip inductor. Please advise.... thanks Jim |
type/length of wire and connectors for external antenna?
On Sun, 11 Oct 2009 18:28:53 -0700, JimK wrote:
Thanks iane. What are the advantages of the balun, vs the long wire? The balun drives co-ax cable. Terminate the random wire away from the electrical noise near the receiver by using co-ax and the balun. |
type/length of wire and connectors for external antenna?
On Oct 11, 7:25*pm, dave wrote:
On Sun, 11 Oct 2009 18:28:53 -0700, JimK wrote: Thanks iane. What are the advantages of the balun, vs the long wire? - The balun drives co-ax cable. First the Balun effectively 'couples' the Antenna Wire to the Coax Cable {Impedance Matching}. [Balun = RF Matching Transformer] Note the Coax Cable [50 Ohms] is already 'Impedance Matched' to the Radio/Receivers 50 Ohm [LO-Z] Antenna Input. -*Terminate the random wire away from the - electrical noise near the receiver by using - co-ax and the balun. Generally a Balun works best along with a good earthen Ground {connection}. |
type/length of wire and connectors for external antenna?
Hello Jim,
On 11 oct, 18:10, JimK wrote: On Oct 4, 4:15*am, Wimpie wrote: On 2 oct, wrote: I'd like to try an external antenna, but one was not included with my G5. What type ofwireshould I get (stranded, solid, gauge, insulated...), and do I just solder it to the pos or neg lead of a miniplug to go into the ext antenna receptacle? Thanks.... Jim Hello Jim, Every type of metalwirewill work for you situation (solid, stranded, plasticized galvanized washing line, etc). Most modern SW receivers with internal antennas are very sensitive, but cannot handle strong signals, so longer will not always be better. To reduce the interference from electronic equipment close to your SW receiver, you may put a coaxial cable between the actual antenna and the receiver. You can use any type of 75, 90 or 50 Ohms cable. The center conductor goes to the center pin of the mini plug and the bread goes to the ground of the mini plug. The antenna side of the cable needs some clarification. The antennawiregoes to the center conductor of the cable, the braid should be connected to ground outside your house (or at least far away from where you expect or have interference). What is "ground"? *When you live in an apartment, it can be the metal fence or railing of the balcony. *You can use a ground rod or any other large metallic structure outside your house. Connect the braid of the cable directly to the ground structure. Do not insert a long run ofwirebetween the metal structure and the braid of the coaxial cable. For some form of static / impulse protection you may add a 1 3 uH inductor between the center conductor and the braid. Note that this inductor will attenuate AM broadcast band reception. As others said, you have to experiment with the orientation of thewireto get best signal/noise ratio. When you are very limited in space for thewire, you may use some 5..10 feet of chicken mesh as reception antenna or use more wires in a fan shape. Best regards, Wim PA3DJSwww.tetech.nl please remove abc when using PM. OK, sorry, I see I was confusing the antenna and radio sides of the coax. The radio side: center of coax to center of mini, shield brain to surround of mini. * OK Antenna side: braid to ground post, center to antenna wire. So I can have the run between outside ground post and radio using coax. OK, working this way avoids that the cable picks up interference from domestic equipment. But can I damage G5 with an external wire? If so I'll use the whip inductor. Please advise.... Yes, you can, as most of these portable recievers do not have strong input protection, nearby strikes can damage the input. Don't make the wire longer then necessary and remove the mini plug from the radio in case of natural photo flash. You might add the inductor or resistor to lower the risk on damage because of built-up of static electricity. Using a special transformer as mentioned in other postings gives you more signal output in case of short wires. So you can have a shorter wire (for example when you have limited space). I do not share the opinion that these transformers reduce interference significantly. When you live in a residential area, you probably don't need this as noise will be dominant with moderate wire lengths. More signal does not always mean better reception as noise will raise also. thanks Jim Best regards, Wim PA3DJS www.tetech.nl |
type/length of wire and connectors for external antenna?
Thanks again, everyone.
But can I damage G5 with an external wire? If so I'll use the whip inductor. Please advise.... Yes, you can, as most of these portable recievers do not have strong input protection, *nearby strikes can damage the input. *Don't make the wire longer then necessary and remove the mini plug from the radio in case of natural photo flash. You might add the inductor or resistor to lower the risk on damage because of built-up of static electricity. Wim (or anyone), So, an early post stated "the longer the better" but you say not so long. What is a good length to try? I assume I'll want to experiment with longer and shorter. Bought 24 gauge speaker wire, 100 ft. for $6.50 at Home Depot. But I'm nervous now, I don't want to do anything until I understand. I presume you mean, disconnect the antenna during storms with lightening flashes. OK. So, I'm thinking there are three kinds of potential damage from a long wi static, lightening, and overload from a strong signal. There are four ways to connect the antenna that I've encountered: miniplug into antenna out, alligator clip to whip, bare wire wrapped around whip, and inductive coupler (insulated wire wrapped around tube placed over whip). (Leaving the balun out for the moment) Am I right that too strong a radio signal (from too long a wire) can hurt the radio? I presume this is true anytime too strong a signal reaches the inside electronics. But my brother tells me the whip is connected to an internal amplifier that the antenna input jack is not connected to. So maybe the antenna input jack is safe in terms of overloading signal from the long wire. And maybe the inductor can also induce too strong a signal in the antenna which is then amplified, causing damage, is this so? So, connecting the wire via the antenna out jack and miniplug is safe with regard to overload, but inductive coupler, alligator clip on whip, and bare wire wrapping around whip (i.e., all connections to whip) are not. True? As for lightening, it seems all connection methods are dangerous. For static, all but the inductive coupler are dangerous. Right? Using a special transformer as mentioned in other postings gives you more signal output in case of short wires. So you can have a shorter wire (for example when you have limited space). I do not share the opinion that these transformers *reduce interference significantly. When you live in a residential area, you probably don't need this as noise will be dominant with moderate wire lengths. * More signal does not always mean better reception as noise will raise also. If I can figure out how to safely connect the antenna to the radio, then is a good way to solve this noise issue to use a very long wire? Or will it just pick up more residential EMG noise? I am in a residential area, I have apartment buildings on two sides, 100+ feet away, house on third side. Maybe tuning to wavelengths is the only way to get a wire to elevate signal above noise. Thanks very much! Jim |
type/length of wire and connectors for external antenna?
-*Terminate the random wire away from the - electrical noise near the receiver by using - co-ax and the balun. Generally a Balun works best along with a good earthen Ground {connection}. *. Dave and RHF, thanks. I'll read up on the balun. What is the purpose of impedence (or RF?) matching between random wire and coax? Thanks, Jim |
type/length of wire and connectors for external antenna?
On Oct 17, 10:32*pm, JimK wrote:
-*Terminate the random wire away from the - electrical noise near the receiver by using - co-ax and the balun. Generally a Balun works best along with a good earthen Ground {connection}. *. Dave and RHF, thanks. I'll read up on the balun. What is the purpose of impedence (or RF?) matching between random wire and coax? Thanks, Jim JIM K - Here is a visualization explanation that is not technically correct. The Long Wire Matching Transformer {Balun/UnUn} incorporates a HI-Z Winding and a LO-Z Winding plus an effective {efficient} means of 'coupling' {energy transfer} which is usually a Ferrite Core. -coupling- The 'nominal' Impedance of a long wire {random wire} Antenna is 450~500 Ohms [HI-Z] and captures the RF Signal {relative Higher Voltage and Lower Current}. -to- The 'nominal' Impedance of a Coax Cable is 50~75 Ohms [LO-Z] and conducts the RF Signal {relative Lower Voltage and Higher Current}. NOTE - The Balun/UnUn is an Matching Transformer that is designed to work/operate at Radio Frequencies. Consider the common wall-wart 120VAC to 6VDC that is designed to work/operate at AC Power {50~60 Hz} Low Frequency : It too is a Transformer. For a more technical explanation of Baluns read : Electrical Impedance http://en.wikipedia.org/wiki/Electrical_impedance Characteristic {Nominal} Impedance http://en.wikipedia.org/wiki/Characteristic_impedance Impedance Matching http://en.wikipedia.org/wiki/Impedance_matching Balun http://en.wikipedia.org/wiki/Balun Impedance Matching Transformers http://www.bcae1.com/trnimpmt.htm http://www.allaboutcircuits.com/vol_2/chpt_9/7.html Impedance Matching Transformers for Receiving Antennas http://www.dxing.info/equipment/impe...ing_bryant.pdf How RF Transformers Work http://www.minicircuits.com/pages/pdfs/howxfmerwork.pdf * About RF Transformers http://www.minicircuits.com/pages/pdfs/tran14-2.pdf Wide Band RF Transformers http://www.electronics-tutorials.com...ansformers.htm Broadband Receiving Antenna Matching http://www.qsl.net/wa1ion/bev/bb_antenna_matching.pdf hope this helps - iane ~ RHF |
type/length of wire and connectors for external antenna?
JimK wrote:
- Terminate the random wire away from the - electrical noise near the receiver by using - co-ax and the balun. Generally a Balun works best along with a good earthen Ground {connection}. . Dave and RHF, thanks. I'll read up on the balun. What is the purpose of impedence (or RF?) matching between random wire and coax? Thanks, Jim Think of "impedance" as hose diameter. You can dump water from a skinny hose (low Z) into a fat hose (Hi Z) but not the other way around (most of the water is spilled). The matching "Bal Un" is usually an autotransformer which converts the 450 Ohms (max Z of the random wire) to 50 Ohms (good match for RG-58, RG-59, RG-6, RG-8X, etc.) Note that at resonance, the random wire is already at 50 Ohms, so the transformer lowers it to ca. 6 Ohms, but it works fine for receiving). A second benefit is that the "BalUn" is DC grounded everywhere (provided you ground the cable sheath where it enters your house per NEC). This will keep static charges out of your radio. Your brother is right. Whips are usually "active" antennas, with an extra transistor to convert the Hi Z antenna to Low-Z, to match the EXT ANT input, which you should use, if you have a proper coaxial deed. |
type/length of wire and connectors for external antenna?
Hello Jim, I put my comment between your text
On 18 oct, 07:26, JimK wrote: Thanks again, everyone. But can I damage G5 with an external wire? If so I'll use the whip inductor. Please advise.... Yes, you can, as most of these portable recievers do not have strong input protection, nearby strikes can damage the input. Don't make the wire longer then necessary and remove the mini plug from the radio in case of natural photo flash. You might add the inductor or resistor to lower the risk on damage because of built-up of static electricity. Wim (or anyone), So, an early post stated "the longer the better" but you say not so long. What is a good length to try? I assume I'll want to experiment with longer and shorter. Bought 24 gauge speaker wire, 100 ft. for $6.50 at Home Depot. But I'm nervous now, I don't want to do anything until I understand. As you are in a residential area, start with about 20 ft. there may be some bends in the wire (for example some part horizontally, some vertically. I checked the I-manual. The receiver has a DX/LOC switch. When you are listening to a weak station and the clearness doesnt reduce when switching from DX to LOC, your wire is long enough (maybe somewhat to long for that particular frequency band). I presume you mean, disconnect the antenna during storms with lightening flashes. OK. Correct. So, I'm thinking there are three kinds of potential damage from a long wi static, lightening, and overload from a strong signal. OK, If there is no DC bath between the inner conductor and the shield of the cable, you can have build-up of static charge that may damage the input circuitry. Strong overload (due to strong stations) will very likely not damage the input, but may result in bad reception of signals at certain frequency bands. There are four ways to connect the antenna that I've encountered: miniplug into antenna out, alligator clip to whip, bare wire wrapped around whip, and inductive coupler (insulated wire wrapped around tube placed over whip). (Leaving the balun out for the moment). In my opinion, the insulated wire wrapped around a tube place over the whip, looks like inductive coupling, but is capacitive coupling (no direct electrical connection between wire and whip). This method of coupling reduces the coupling for low frequency. By varying the number of turns you can figure out the best coupling to your receiver. That means sufficient signal from the antenna to overcome the receiver noise, but not too much to get intermodulation (overload) problems. Am I right that too strong a radio signal (from too long a wire) can hurt the radio? I think not, see text above. I presume this is true anytime too strong a signal reaches the inside electronics. But my brother tells me the whip is connected to an internal amplifier that the antenna input jack is not connected to. So maybe the antenna input jack is safe in terms of overloading signal from the long wire. Depends on type of receiver, I don't know the inside of the G5. And maybe the inductor can also induce too strong a signal in the antenna which is then amplified, causing damage, is this so? So, connecting the wire via the antenna out jack and miniplug is safe with regard to overload, but inductive coupler, alligator clip on whip, and bare wire wrapping around whip (i.e., all connections to whip) are not. True? Many portable receivers show overload problems when connecting long wire (for example 100ft) directly to the whip (electrically connected). By wrapping the insulated wire around the whip, you reduce the coupling (especially for the low frequency ranges like AM and LW), hence reducing change of overload. As for lightening, it seems all connection methods are dangerous. For static, all but the inductive coupler are dangerous. Right? Depends. When the wire is insulated from the antenna (what you call inductive coupling), static charge may build-up until it reaches the ultimate strength of the insulation. When exceeded, your whip might be subjected to static discharge. You can bleed the static charge by providing a DC path to ground. Mostly when the bare antenna wire touches the building construction (wood, concrete, etc), static charge will not build-up. Using a special transformer as mentioned in other postings gives you more signal output in case of short wires. So you can have a shorter wire (for example when you have limited space). I do not share the opinion that these transformers reduce interference significantly. When you live in a residential area, you probably don't need this as noise will be dominant with moderate wire lengths. More signal does not always mean better reception as noise will raise also. If I can figure out how to safely connect the antenna to the radio, then is a good way to solve this noise issue to use a very long wire? Or will it just pick up more residential EMG noise? I am in a residential area, I have apartment buildings on two sides, 100+ feet away, house on third side. You may try this. When you have a significant part of the wire outside, away from electronics, that will improve reception, but be aware of overload as mentioned earlier (so use the capacitive coupling with the insulated wire wrapped around the whip). Note that this is not my favorite solution (I prefer the coaxial feed and have all antenna parts away from electronics). Maybe tuning to wavelengths is the only way to get a wire to elevate signal above noise. Sorry Jim, I don't understand what you mean. Thanks very much! Jim I hope my response is not too confusing. Best regards, Wim PA3DJS www.tetech.nl without abc, you have a valid address. |
type/length of wire and connectors for external antenna?
Am I right that too strong a radio signal (from too long a wire) can hurt the radio? Depends on the radio. The input gain device may be adversely affected by too strong a signal. Being driven into saturation can result in failure of some devices. This was a problem with some Sony radios. It was a problem on a few inexpensive radios. It was a problem on a number of early solidstate radios. Today, receivers have overload protection before the first active device. Sony installed diodes before the front end of their affected devices. And most input devices used today have sufficient headroom in circuit to prevent front end overload in all but the most extreme cases. Buffers, and IF amps will more quickly overload than many front ends, today. But if you're talking about SW, unless you're near Antigua, or living in Western Europe, you're not likely to encounter signals strong enough to cause overload problems. A few domestic SW players, if you're close enough. But not nearly what it used to be. So, depending on your location, your concern may be a non-issue. That said, it's something that's worth bearing in mind. |
type/length of wire and connectors for external antenna?
In message , dave
writes JimK wrote: - Terminate the random wire away from the - electrical noise near the receiver by using - co-ax and the balun. Generally a Balun works best along with a good earthen Ground {connection}. . Dave and RHF, thanks. I'll read up on the balun. What is the purpose of impedence (or RF?) matching between random wire and coax? Thanks, Jim Think of "impedance" as hose diameter. You can dump water from a skinny hose (low Z) into a fat hose (Hi Z) but not the other way around (most of the water is spilled). That's a rather unfortunate analogy. To the flow of water, a skinny hose would have a high impedance, and a fat hose would have a low impedance. But the principle is 'sort of' correct. The matching "Bal Un" is usually an autotransformer which converts the 450 Ohms (max Z of the random wire) to 50 Ohms (good match for RG-58, RG-59, RG-6, RG-8X, etc.) Note that at resonance, the random wire is already at 50 Ohms, so the transformer lowers it to ca. 6 Ohms, but it works fine for receiving). Although it's certainly high, I don't think that the maximum impedance of a random wire is limited to 450 ohms. Nevertheless, the transformer still provides a better match than you would get with a direct connection between the coax and the wire, and you don't lose as much signal. At frequencies where the wire presents a relatively low impedance, the transformer may transform the impedance of the antenna to a value a lot less than the coax. On those frequencies, you could actually get less signal than you would if there had been a direct connection. However, it's a case of swings and roundabouts. For most of the spectrum between (say) 1 and 30MHz, you will get more signal (and, on some frequencies, quite a lot more). On a few relatively narrow parts of the spectrum, you will get somewhat less. A second benefit is that the "BalUn" is DC grounded everywhere (provided you ground the cable sheath where it enters your house per NEC). This will keep static charges out of your radio. You don't really need an un-un to do this. You can add an RF choke (or high-ish value resistor) at some point across the coax. This won't do much for lightning protection, but it will prevent the build-up of a static charge on the wire. However, an un-un will probably give you more against the effects of nearby lightning strikes. You should at least provide a good ground for the coax screen at the antenna feedpoint. Hopefully, this will be remote from the house. For good luck, you can also ground it where it enters the house (and anywhere else you care to along its length), but it's the ground at the antenna end which is the most important. Your brother is right. Whips are usually "active" antennas, with an extra transistor to convert the Hi Z antenna to Low-Z, to match the EXT ANT input, which you should use, if you have a proper coaxial deed. -- Ian |
type/length of wire and connectors for external antenna?
Ian Jackson wrote:
You should at least provide a good ground for the coax screen at the antenna feedpoint. Hopefully, this will be remote from the house. For good luck, you can also ground it where it enters the house (and anywhere else you care to along its length), but it's the ground at the antenna end which is the most important. I've never bothered and have had good results. |
type/length of wire and connectors for external antenna?
In message , dave
writes Ian Jackson wrote: You should at least provide a good ground for the coax screen at the antenna feedpoint. Hopefully, this will be remote from the house. For good luck, you can also ground it where it enters the house (and anywhere else you care to along its length), but it's the ground at the antenna end which is the most important. I've never bothered and have had good results. I'm sure you have. However, it's nice if the 'feedpoint' of the antenna goes through the primary (high impedance) winding of the un-un, and straight to a good RF ground. And, as you have a good RF ground, you might as well connect the coax screen to it too. The screen should remain pretty well RF-dead all the way back to the receiver, but there's no harm in grounding it at other points along its length to ensure absolutely zero pickup of noise on the coax. -- Ian |
type/length of wire and connectors for external antenna?
Ian Jackson wrote:
In message , dave writes Ian Jackson wrote: You should at least provide a good ground for the coax screen at the antenna feedpoint. Hopefully, this will be remote from the house. For good luck, you can also ground it where it enters the house (and anywhere else you care to along its length), but it's the ground at the antenna end which is the most important. I've never bothered and have had good results. I'm sure you have. However, it's nice if the 'feedpoint' of the antenna goes through the primary (high impedance) winding of the un-un, and straight to a good RF ground. And, as you have a good RF ground, you might as well connect the coax screen to it too. The screen should remain pretty well RF-dead all the way back to the receiver, but there's no harm in grounding it at other points along its length to ensure absolutely zero pickup of noise on the coax. Once the feed point is in the air, the "ground" lead is a "good RF ground" at some frequencies, and half an asymmetric dipole on others. Grounding it at several points won't help at some freqs, specifically those where the distance to real ground (or between any other elements) is 0.25 wavelengths. You quite possibly will have more of an antenna than a ground. |
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