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"Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Inductance isn't all there is to an antenna.. you need capture area, too. Broomstick antennas are not all that good, and are not very efficient. Yes, they look good on paper, as the 'electrical length' is much longer than that much straight wire, but without capture area, the efficeincy drops way off. You're better with a longwire, even just a few meters (yards) run along the eaves of your house. |
I won't go into detail but the broomstick (or any helicaly wound antenna)
gives up performance for size. The straiter the wire, the better off you are. If you have the space, just stretch it out strait. "Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave |
CW wrote: I won't go into detail but the broomstick (or any helicaly wound antenna) gives up performance for size. The straiter the wire, the better off you are. If you have the space, just stretch it out strait. Experimentation and experience have taught me that this is basically correct. "Broomstick" antennas give pretty good performance in a very compact space - they are even (marginally) "portable". But for signal-pulling ability, they'll never beat a well-thought-out longwire or randomwire. If you can tuck a one-meter broomstick into your car somewhere for traveling, you've got the world by the butt for shortwave listening away from home. But at home - your "permanent space" - go with a random or longwire, if you possibly can. Tony "Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
Hmm. Okay. Only I don't have much outside space available. I *might* be
able to manage 20-30 feet of random wire, but that is about it. And I have more than a mile of small-guage wire on these two spools. I was planning on wrapping it around a five-foot long piece of 4 inch PVC and standing it behind a closet door. Since my last last message I tried a very crude "hook-up" with one of the spools of wire and got absolutely no improvement in reception. Now I understand why, thanks to you good people. Back to the 20-30' piece of random wi my only option is to run it out the window and along the top rail of the fence in the back yard. Would this really outdo a massive broomstick antenna? Thanks for the input. You've all got me thinking. Dave "Tony Meloche" wrote in message ... CW wrote: I won't go into detail but the broomstick (or any helicaly wound antenna) gives up performance for size. The straiter the wire, the better off you are. If you have the space, just stretch it out strait. Experimentation and experience have taught me that this is basically correct. "Broomstick" antennas give pretty good performance in a very compact space - they are even (marginally) "portable". But for signal-pulling ability, they'll never beat a well-thought-out longwire or randomwire. If you can tuck a one-meter broomstick into your car somewhere for traveling, you've got the world by the butt for shortwave listening away from home. But at home - your "permanent space" - go with a random or longwire, if you possibly can. Tony "Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
The currrent in the wire produces an electromagnetic field which has a
defined radius. The field coil of a motor is used to turn it into a magnet so the motor will work...stretch out the windings, no emf imposed upon the core..no magnet-action-no work Stretch it out, you exceed the radius of the electromagnetic field, no interaction, no function. The whole purpose of the antenna in coil-structure is to use the induced emf to create a load on the antenna so it "thinks" it is longer Yodar "Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave |
Brenda et al:
This statement facinates me: related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. 1.2 kM of wire; Heck of a lot of capture area ! Is there some ratio of loop diameter and spacing between the wire loops that results in the most capture area? There is a nice ratio of mirror diameter to magnification limits in telescopes This is the analogy I was thinking of. Dan Inductance isn't all there is to an antenna.. you need capture area, too. Broomstick antennas are not all that good, and are not very efficient. Yes, they look good on paper, as the 'electrical length' is much longer than that much straight wire, but without capture area, the efficeincy drops way off. You're better with a longwire, even just a few meters (yards) run along the eaves of your house. |
Tony Meloche wrote:
CW wrote: I won't go into detail but the broomstick (or any helicaly wound antenna) gives up performance for size. The straiter the wire, the better off you are. If you have the space, just stretch it out strait. snip If you can tuck a one-meter broomstick into your car somewhere for traveling, you've got the world by the butt for shortwave listening away from home. But at home - your "permanent space" - go with a random or longwire, if you possibly can. Tony For portable use, I've found the AT-271/A antenna designed for the PRC-25 or PRC-77 works quite well. It's about 10' long, and it's set up like the supports used for dome tents - to take it down - you pull the sections apart (they have a chain/shock cord running through them) and fold them for storage. I got it he http://www.american-milspec.com/c765.html Unfortunately, it's just a hair too long to fit inside the aluminum attaché case I transport my 7030 in. Personally, I think I'd use a slinky over a broom stick. More compact for travel, and if you have more room, you can spread it out. "Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
"Brenda Ann" wrote in message ... "Dave" wrote in message ... Hmm. Okay. Only I don't have much outside space available. I *might* be able to manage 20-30 feet of random wire, but that is about it. And I have more than a mile of small-guage wire on these two spools. I was planning on wrapping it around a five-foot long piece of 4 inch PVC and standing it behind a closet door. Since my last last message I tried a very crude "hook-up" with one of the spools of wire and got absolutely no improvement in reception. Now I understand why, thanks to you good people. Back to the 20-30' piece of random wi my only option is to run it out the window and along the top rail of the fence in the back yard. Would this really outdo a massive broomstick antenna? Almost anything will outdo a broomstick antenna. 30' of longwire along your fence (presuming it is wood, and not steel) would do a great job. Even better still would be to run it around your rafters (presuming again that they are not concrete or aluminum siding or such). Either way, I would use some kind of standoffs (you can find them at hardware stores, or make your own from old thread spools). Okay, so here's the problem. The fence is metal, and the house is covered with steel siding. My DX-402 does pick up BBC on 5975 pretty well with just the whip (next to a window), but VOK is extremely weak to vanishing. (This last one is what I want the broomstick antenna for.) If I do go with the broomstick, should I stick with the five-foot piece that I already have cut, or go with a longer eight-foot piece which will still fit nicely in the corner I have in mind. Or should I go all out with a ten-foot piece (or even multiples maybe) and put it in the attic? Also, what type of ground should I use? I could run a ground wire out the window to a ground rod that is as old as the house, but that's about my only option (the house predates three-prong plugs with a real ground.) I really appreciate your thoughts on these things. You obviously know a lot more about this stuff than I do. Thanks, Dave |
In article , "Dave"
writes: Or should I go all out with a ten-foot piece of 4 inch PVC (or even multiples maybe) and put it in the attic? If the attic is non-metal, I'd try this solution .. |
DAVE,
Concerning the BroomStick Antenna: http://www.hard-core-dx.com/nordicdx.../bromstik.html http://www.hard-core-dx.com/nordicdx...al/broom2.html http://www.hard-core-dx.com/nordicdx.../tunestik.html http://www.hard-core-dx.com/nordicdx.../tunstik2.html IIRC: The 1.2kM of wire was wrapped on a piece of PVC Pipe http://www.hard-core-dx.com/nordicdx...al/broom3.html - - - "improved model is 6 m (18Ft) of 4 Inch OD PVC" (Section of Well Lining that was over 18 Foot Long.) = = = Effectively a 18 Foot Vertical Antenna. "I mounted the 6 m (18Ft) portion vertically, and the 2.5 m (7.5 Ft) section horizontally (a "reverted "L"" system). I added in my 250 m (750 Ft) Random Long Wire (it was there, so why not use it?), grounded the thing and in great anticipation, plugged it into the radio. - - - The results were more than amazing." - by Marty Leipzig HELLO! Forget the BroomStick [.] TBL: This Guy had a 750 Ft Random Wire Antenna ! When your 'think' of a Broom Stick Antenna that has a size small wire tightly wrapped along a length of PVC Pipe. Just consider the piece of PVC Pipe an equal section of Aluminum Tubing; and not much more. Better to try a Eight Foot Section of 2"-3" PVC Pipe with a single wire wrapped in three coils on it. * Use a 500 Foot Spool of #14 AWG Insulated 19 Stranded Wire. * Each "Coil" set to resonate at a different band of your choice. * Each "Coil" spaced 1'-2' apart on the PVC Pipe. IMHO: The BrommStick Antenna is a 'good idea' for Apartment Residents stuck with a single outside facing window. - - - Been There, Done That ! REMEMBER: The ANTENNA + GROUND SYSTEM is . . . 55.5% of the Radio/Receiver and Antenna+Ground Reception Equation. GoTo= http://groups.yahoo.com/group/SWL-AM...na/message/288 All are WELCOME at this "Antenna Ashram" + Who Seek Better Reception + + And a Clear Understanding + + + From That Which Transcends the Ether and Beyond. WHE "SWL Antennas and AM & FM Antennas" eGroup on YAHOO ! - When You NEED to Contemplate the - - "Aerial High" and the - - - "True Meaning of Ground". iane ~ RHF .. .. = = = "Dave" = = = wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave .. |
TM,
Good Accessment of the BroomStick Antenna. iane ~ RHF .. .. = = = Tony Meloche = = = wrote in message ... CW wrote: I won't go into detail but the broomstick (or any helicaly wound antenna) gives up performance for size. The straiter the wire, the better off you are. If you have the space, just stretch it out strait. Experimentation and experience have taught me that this is basically correct. "Broomstick" antennas give pretty good performance in a very compact space - they are even (marginally) "portable". But for signal-pulling ability, they'll never beat a well-thought-out longwire or randomwire. If you can tuck a one-meter broomstick into your car somewhere for traveling, you've got the world by the butt for shortwave listening away from home. But at home - your "permanent space" - go with a random or longwire, if you possibly can. Tony .. |
= = = "Dave"
= = = wrote in message ... Hmm. Okay. Only I don't have much outside space available. I *might* be able to manage 20-30 feet of random wire, but that is about it. =R= Assuming that his is NOT a Metal Fence. Another: [Hidden] "On-the-Fence" Random Wire Antenna HOW TO: Use a short section of Fence for a Low Level "Folded" Random Wire Antenna. * Run a Coax Cable out to the Bottom of the Fence. (Can be TV type 75 Ohm Coax Cable) * Install a Ground Rod / Ground Wire HERE. (If you have a Metal Fence Post Anchors ? Use One as the Ground Point.) * Use a Matching Transformer to connect the Antenna Element to the Coax Cable. (This can be a TV type 30075 Ohm Matching Transformer. * Route the "WIRE" (Antenna Element) from the Starting-End of the Fence; about one foot above and paralell to the ground to the Far-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Starting-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Far-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Starting-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Far-End of the Fence. = = = 100Ft - 150Ft Random Wire Antenna (5 X 20Ft = 100Ft -&- 5 X 30Ft = 150Ft) Sorta - Looka - Lika - Diz: _____________________________x |____________________________ _____________________________| |____________________________ ===MT________________________| ....G......................... .. .. And I have more than a mile of small-guage wire on these two spools. I was planning on wrapping it around a five-foot long piece of 4 inch PVC and standing it behind a closet door. =R= Better to wrap the wire Length-Wise 'inside & out' (over and through) the PVC Pipe with about 1" spacing. This would be about 120 Ft of wire in a vertical format. .. .. Since my last last message I tried a very crude "hook-up" with one of the spools of wire and got absolutely no improvement in reception. Now I understand why, thanks to you good people. Back to the 20-30' piece of random wi my only option is to run it out the window and along the top rail of the fence in the back yard. Would this really outdo a massive broomstick antenna ? =R= ? QUESTION ? "Top Rail" Is this a Metal Fence ? .. .. Thanks for the input. You've all got me thinking. Dave iane ~ RHF .. .. |
"Dave" wrote in message ... Okay, so here's the problem. The fence is metal, and the house is covered with steel siding. My DX-402 does pick up BBC on 5975 pretty well with just the whip (next to a window), but VOK is extremely weak to vanishing. (This last one is what I want the broomstick antenna for.) If I do go with the broomstick, should I stick with the five-foot piece that I already have cut, or go with a longer eight-foot piece which will still fit nicely in the corner I have in mind. Or should I go all out with a ten-foot piece (or even multiples maybe) and put it in the attic? Also, what type of ground should I use? I could run a ground wire out the window to a ground rod that is as old as the house, but that's about my only option (the house predates three-prong plugs with a real ground.) I really appreciate your thoughts on these things. You obviously know a lot more about this stuff than I do. The rafters idea could still work with standoffs, though not as well as with a wood surface. What material is your roof made from? How much of a crown does it have? You could run wire along the crown of the roof with good results. Use coax to get it into the house. Ground the coax outside the house at the point it enters. |
"Dave" wrote in
: I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. I built one. I was quite disappointed after reading all the hype. I get better reception from a wire run around the corners of my bedroom ceiling. |
"donutbandit" wrote in message ... "Dave" wrote in : I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. I built one. I was quite disappointed after reading all the hype. I get better reception from a wire run around the corners of my bedroom ceiling. I woul not anticipate the broomstick antenna to be any different than a metal tube or rod of similar dimensions. Dale W4OP |
|
In article ,
"Dale Parfitt" wrote: "donutbandit" wrote in message ... "Dave" wrote in : I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. I built one. I was quite disappointed after reading all the hype. I get better reception from a wire run around the corners of my bedroom ceiling. I would not anticipate the broomstick antenna to be any different than a metal tube or rod of similar dimensions. Good comparison. A tightly wound broomstick would resemble a rod for receiving purposes. -- Telamon Ventura, California |
"Diverd4777" wrote in message ... In article , "Dave" writes: Or should I go all out with a ten-foot piece of 4 inch PVC (or even multiples maybe) and put it in the attic? If the attic is non-metal, I'd try this solution .. Sorry it took me so long to reply. Christmas, and all. The attic/roof is not-metal, but it is so short that you really can't move around in it. I can stick something up there and more-or-less angle it this way or that, but that's about it. I thought about putting something directional up there, but upon further reflection I really don't see any way to do that. And outside, I could run a wire along the top of the (metal) fence, but that's about it. Thought about putting something under the eaves, and haven't totally given up on that yet. If I did that, I could make it +/- 30 feet long. Still thinking. Thanks for the input. Dave |
"Brenda Ann" wrote in message ... "Dave" wrote in message ... Okay, so here's the problem. The fence is metal, and the house is covered with steel siding. My DX-402 does pick up BBC on 5975 pretty well with just the whip (next to a window), but VOK is extremely weak to vanishing. (This last one is what I want the broomstick antenna for.) If I do go with the broomstick, should I stick with the five-foot piece that I already have cut, or go with a longer eight-foot piece which will still fit nicely in the corner I have in mind. Or should I go all out with a ten-foot piece (or even multiples maybe) and put it in the attic? Also, what type of ground should I use? I could run a ground wire out the window to a ground rod that is as old as the house, but that's about my only option (the house predates three-prong plugs with a real ground.) I really appreciate your thoughts on these things. You obviously know a lot more about this stuff than I do. The rafters idea could still work with standoffs, though not as well as with a wood surface. What material is your roof made from? How much of a crown does it have? You could run wire along the crown of the roof with good results. Use coax to get it into the house. Ground the coax outside the house at the point it enters. The roof is wood with asphalt shingles. But the attic is only about three feet tall (see my reply to diverd4777). With extreme difficulty one can get from one side of the house to the other through the attic, but trying to do this while carrying something is next to impossible. Is that what you are asking about, about the crown? Height, in the attic? If not please let me know. Dave |
"RHF" wrote in message om... = = = "Dave" = = = wrote in message ... Hmm. Okay. Only I don't have much outside space available. I *might* be able to manage 20-30 feet of random wire, but that is about it. =R= Assuming that his is NOT a Metal Fence. It is a metal fence. Chain-link. I didn't think that was a very likely answer to my problems. Another: [Hidden] "On-the-Fence" Random Wire Antenna HOW TO: Use a short section of Fence for a Low Level "Folded" Random Wire Antenna. * Run a Coax Cable out to the Bottom of the Fence. (Can be TV type 75 Ohm Coax Cable) * Install a Ground Rod / Ground Wire HERE. (If you have a Metal Fence Post Anchors ? Use One as the Ground Point.) * Use a Matching Transformer to connect the Antenna Element to the Coax Cable. (This can be a TV type 30075 Ohm Matching Transformer. * Route the "WIRE" (Antenna Element) from the Starting-End of the Fence; about one foot above and paralell to the ground to the Far-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Starting-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Far-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Starting-End of the Fence. * * Then go "UP" Vertically for about a foot. * * Next route the Wire parallel to the ground; back to the Far-End of the Fence. = = = 100Ft - 150Ft Random Wire Antenna (5 X 20Ft = 100Ft -&- 5 X 30Ft = 150Ft) Sorta - Looka - Lika - Diz: _____________________________x |____________________________ _____________________________| |____________________________ ===MT________________________| ...G......................... . . And I have more than a mile of small-guage wire on these two spools. I was planning on wrapping it around a five-foot long piece of 4 inch PVC and standing it behind a closet door. =R= Better to wrap the wire Length-Wise 'inside & out' (over and through) the PVC Pipe with about 1" spacing. This would be about 120 Ft of wire in a vertical format. . I'm not sure how I could do that, at least with my 5-foot piece of PVC. Any ideas? . Since my last last message I tried a very crude "hook-up" with one of the spools of wire and got absolutely no improvement in reception. Now I understand why, thanks to you good people. Back to the 20-30' piece of random wi my only option is to run it out the window and along the top rail of the fence in the back yard. Would this really outdo a massive broomstick antenna ? =R= ? QUESTION ? "Top Rail" Is this a Metal Fence ? . . Thanks for the input. You've all got me thinking. Dave iane ~ RHF . . Dave |
"Joe Strain" wrote in message om... The currrent in the wire produces an electromagnetic field which has a defined radius. The field coil of a motor is used to turn it into a magnet so the motor will work...stretch out the windings, no emf imposed upon the core..no magnet-action-no work Stretch it out, you exceed the radius of the electromagnetic field, no interaction, no function. The whole purpose of the antenna in coil-structure is to use the induced emf to create a load on the antenna so it "thinks" it is longer Yodar Read this a couple days ago, and am still trying to wrap my brain around it. Will try to reply in more depth 12/25 or 12/26 Dave "Dave" wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave |
Thanks for the links. The website for the first four was where I got my
original information, but I couldn't remember where it was. I appreciate it. Thanks also for hte Yahoo link. I'm going to check that out. Dave "RHF" wrote in message om... DAVE, Concerning the BroomStick Antenna: http://www.hard-core-dx.com/nordicdx.../bromstik.html http://www.hard-core-dx.com/nordicdx...al/broom2.html http://www.hard-core-dx.com/nordicdx.../tunestik.html http://www.hard-core-dx.com/nordicdx.../tunstik2.html IIRC: The 1.2kM of wire was wrapped on a piece of PVC Pipe http://www.hard-core-dx.com/nordicdx...al/broom3.html - - - "improved model is 6 m (18Ft) of 4 Inch OD PVC" (Section of Well Lining that was over 18 Foot Long.) = = = Effectively a 18 Foot Vertical Antenna. "I mounted the 6 m (18Ft) portion vertically, and the 2.5 m (7.5 Ft) section horizontally (a "reverted "L"" system). I added in my 250 m (750 Ft) Random Long Wire (it was there, so why not use it?), grounded the thing and in great anticipation, plugged it into the radio. - - - The results were more than amazing." - by Marty Leipzig HELLO! Forget the BroomStick [.] TBL: This Guy had a 750 Ft Random Wire Antenna ! When your 'think' of a Broom Stick Antenna that has a size small wire tightly wrapped along a length of PVC Pipe. Just consider the piece of PVC Pipe an equal section of Aluminum Tubing; and not much more. Better to try a Eight Foot Section of 2"-3" PVC Pipe with a single wire wrapped in three coils on it. * Use a 500 Foot Spool of #14 AWG Insulated 19 Stranded Wire. * Each "Coil" set to resonate at a different band of your choice. * Each "Coil" spaced 1'-2' apart on the PVC Pipe. IMHO: The BrommStick Antenna is a 'good idea' for Apartment Residents stuck with a single outside facing window. - - - Been There, Done That ! REMEMBER: The ANTENNA + GROUND SYSTEM is . . . 55.5% of the Radio/Receiver and Antenna+Ground Reception Equation. GoTo= http://groups.yahoo.com/group/SWL-AM...na/message/288 All are WELCOME at this "Antenna Ashram" + Who Seek Better Reception + + And a Clear Understanding + + + From That Which Transcends the Ether and Beyond. WHE "SWL Antennas and AM & FM Antennas" eGroup on YAHOO ! - When You NEED to Contemplate the - - "Aerial High" and the - - - "True Meaning of Ground". iane ~ RHF . . = = = "Dave" = = = wrote in message ... I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. Got a question though: doesn't "stretching out" the coil to a meter or more reduce the inductance of the resulting coil? Why wouldn't it work better to just leave it on the spool? I was under the impression that the formula for calculating the inductance for a given coil involved multiplying the square of the number of coils by the ratio of the coil width to length. Wouldn't this mean that a "longer" coil would have a lower inductance than a "shorter" coil, given the same length of wire and approximate diameter of coils? Forgive me if I'm being stupid here, it has been twenty years since I have attempted anything like this, but that was what I thought. The main account I am thinking of was related by someone in Saudi Arabia who wrapped 1.2 kM of wire around a piece of PVC and vastly improved their reception of WWV in the states. I was going to do something similar, and then looked at the two spools of wire that I was about to unwrap. They are already coils, so shouldn't I be able to just hook them up to an aligator clip and stick this to my whip antenna? (I am now thinking about taking the wire off of the smaller spool and adding it to the larger. Shouldn't that work?) And if I leave the wire on the spools (which are plastic) couldn't I turn them toward or away from the station of interest to further improve reception? (I could even put this in my attic, gaining a few feet of elevation and hiding it from my unappreciative wife.) Any input on any part of this idea is more than welcome. I would greaty value the opinions of those who have actually done something like one of these two options. Thanks, Dave . |
"Telamon" wrote in message ... In article , "Dale Parfitt" wrote: "donutbandit" wrote in message ... "Dave" wrote in : I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. I built one. I was quite disappointed after reading all the hype. I get better reception from a wire run around the corners of my bedroom ceiling. I would not anticipate the broomstick antenna to be any different than a metal tube or rod of similar dimensions. Good comparison. A tightly wound broomstick would resemble a rod for receiving purposes. -- Telamon Ventura, California Still true, even if each turn of wire is insulated from those adjacent to it? How could that be? Thanks, Dave |
"Dave" wrote in message ... The roof is wood with asphalt shingles. But the attic is only about three feet tall (see my reply to diverd4777). With extreme difficulty one can get from one side of the house to the other through the attic, but trying to do this while carrying something is next to impossible. Is that what you are asking about, about the crown? Height, in the attic? If not please let me know. The crown of the roof is the pointed top (outside). ^ === crown / \ | | |
Dave wrote:
It is a metal fence. Chain-link. I didn't think that was a very likely answer to my problems. I'd be curious as to why running a wire along a metal fence would be such a problem. I just ran about 200 feet of wire along the top of a wire fence (2 inch square openings), albeit the type that is covered with some green vinyl. And I have noticed CONSIDERABLE improvement in reception. Wouldn't attaching to so much metal just help to expand the range of the antenna? Also, related to the metal fence thing: what would happen were I to attach a wire to my metal roof? And as long as we're on the subject of random wire, what's the deal with needing "stranded" wire. I had about 100 feet of that first, and then when I went to buy some more all they had was single strand, so I bought that and just added that to the end of the stranded. what's the importance/need of using stranded? av |
AV wrote: Dave wrote: It is a metal fence. Chain-link. I didn't think that was a very likely answer to my problems. I'd be curious as to why running a wire along a metal fence would be such a problem. I just ran about 200 feet of wire along the top of a wire fence (2 inch square openings), albeit the type that is covered with some green vinyl. And I have noticed CONSIDERABLE improvement in reception. Wouldn't attaching to so much metal just help to expand the range of the antenna? Also, related to the metal fence thing: what would happen were I to attach a wire to my metal roof? And as long as we're on the subject of random wire, what's the deal with needing "stranded" wire. I had about 100 feet of that first, and then when I went to buy some more all they had was single strand, so I bought that and just added that to the end of the stranded. what's the importance/need of using stranded? av As far as ability to pick up RF signal, I'm not aware that there *is* a bit of difference. Stranded is a bit stronger, perhaps, but if anyone ever told you you "had" to use stranded for antenna wire, I'd be intersted in hearing their justification for that. Tony ----== Posted via Newsfeed.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeed.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= 19 East/West-Coast Specialized Servers - Total Privacy via Encryption =--- |
TM,
Antennas - WHY - Stranded Wire is a 'little' Better. 1. More Flexible and Less Breakage. 2. If you use a Single Strand (1) type Wire. When the One Strand Breaks the Wire Has Failed. 3. If you use a Multi-Stranded (19) type Wire. When the One to Three Strands Breaks the Wire Has NOT Failed; and you still have a Wire that would be rated at about 85%. NOTE: Nineteen Stranded Wire has a Single Strand; that is Surounded by Six Strands (Optimum Re-inforcement); that is Surounded by Twelve Strands (Optimum Re-inforcement); {Like A Bridge Support Cable} Then Covered by Insulation. 4. IIRC: For the same AWG Size Wire the Stranded Wire is Rated as Stronger and Lighter then the Single Strand Wire. 5. RF Wise - Multi-Strand Wire has more Surface Area for RF to Travel On. So specialty Antenna Wires like * "QuietFlex" (41 Strand @ #14 AWG) * "Flex-Weave" (168 Strands @ #14 AWG) Can Actually (In-Fact) make a' difference' in your Reception. ? NOW ? IS ? ANY ? OF ? THIS ? TRUE ? REMEMBER: The Antenna & Ground System is 55.5% of the Radio/Receiver and Antenna/Ground Reception Equation. http://groups.yahoo.com/group/SWL-AM...na/message/288 WHE "SWL Antennas and AM & FM Antennas" eGroup on YAHOO ! - When You NEED to Contemplate the - - "Aerial High" and the - - - "True Meaning of Ground". iane ~ RHF All are WELCOME at this "Antenna Ashram" + Who Seek Better Reception + + And a Clear Understanding + + + From That Which Transcends the Ether and Beyond. .. .. = = = Tony Meloche = = = wrote in message ... AV wrote: Dave wrote: It is a metal fence. Chain-link. I didn't think that was a very likely answer to my problems. I'd be curious as to why running a wire along a metal fence would be such a problem. I just ran about 200 feet of wire along the top of a wire fence (2 inch square openings), albeit the type that is covered with some green vinyl. And I have noticed CONSIDERABLE improvement in reception. Wouldn't attaching to so much metal just help to expand the range of the antenna? Also, related to the metal fence thing: what would happen were I to attach a wire to my metal roof? And as long as we're on the subject of random wire, what's the deal with needing "stranded" wire. I had about 100 feet of that first, and then when I went to buy some more all they had was single strand, so I bought that and just added that to the end of the stranded. what's the importance/need of using stranded? av As far as ability to pick up RF signal, I'm not aware that there *is* a bit of difference. Stranded is a bit stronger, perhaps, but if anyone ever told you you "had" to use stranded for antenna wire, I'd be intersted in hearing their justification for that. Tony .. |
RHF wrote:
? NOW ? IS ? ANY ? OF ? THIS ? TRUE ? . sounds pretty plausible to me, but then i'm the one who asked the question, and i'm a fairly gullible person. as for the strength question, multi-strand didn't withstand an avalanche of snow coming off the roof and breaking it, nor did it withstand my puppy biting it into a few pieces. i kinda doubt there is really too much difference in strength. the fact that stranded allows for the breakage of one strand while leaving the others intact, but just the same, those single threads are thinner and more likely to break in the first place! as for surface area, that sounds plausible, but then that brings it back to the metal fence question. if it's surface area you want, then why the warning not to lay a random wire along a metal fence. wouldn't the fence be helpful in reception and pass things along into the wire? av |
DAVE,
Understanding the "BroomStick" Antenna and its Coil. = WHY = Three Shorter Coils may Work Better then One Long Coil. First: Lets take a Eight Foot (8Ft) piece of One Inch (1") Outside Diameter (OD) PVC Pipe. (This is our BroomStick Antenna "FORM".) Second: Take a Single piece of #14 AWG Stranded Insulated Wire and stretch it out along the length of the PVC Pipe. What Do We Have? A Vertical Antenna Element - That happens to be 1/4 of a Wave Length (WL) in the range of 31 MHz. Third: Take a Single piece of #14 AWG Stranded Insulated Wire and stretch it out along the length of the PVC Pipe and form a Coil of 11 Turns (about 1") at the Bottom. What Do We Have? A "LOADED" Vertical Antenna Element - That happens to act like 1/4 of a Wave Length (WL) in the range of 10 MHz. Fourth: Take a Single piece of #14 AWG Stranded Insulated Wire and stretch it out along the length of the PVC Pipe and form a Coil of 66 Turns (about 6") at the Bottom. What Do We Have? A "LOADED" Vertical Antenna Element - That happens to act like 1/4 of a Wave Length (WL) in the range of 1 MHz. Fifth: Take a Single piece of #14 AWG Stranded Insulated Wire and stretch it out along the length of the PVC Pipe and form a Coil of 460 Turns (about 2Ft) at the Bottom. What Do We Have? A "LOADED" Vertical Antenna Element - That happens to act like 1/4 of a Wave Length (WL) for about 100 kHz. CONCLUSION: The Conclusion That We Must Draw From The Above Is: That the common BroomStick Antenna that has wire closely wound on a piece of PVC Pipe to FORM a Coil of 3Ft, 5Ft, or all of the 8Ft; must be resonant well below 100 kHz. THEREFO Therefore for 31 MHz, 10 MHz, 1MHz and anything in-between: The BroomStick Antenna simply looks effectively like a 1/4 WL Antenna Element that works so-so in the range of 31 MHz. = = = Effectively like a 1" Copper Pipe. BETTER: The Better Alternative is to Start over by taking a Eight Foot (8Ft) piece of One Inch (1") Outside Diameter (OD) PVC Pipe. (This is our BroomStick Antenna "FORM".) Next, take a single piece of #14 AWG Stranded Insulated Wire and wrap three coils on the PVC Pipe. * "Concerning the BroomStick Antenna" Read Message #410 GoTo= http://groups.yahoo.com/group/SWL-AM...na/message/410 * "Image of Tri-Band 'BroomStick' Antenna" GoTo= http://groups.yahoo.com/group/SWL-AM...na/message/412 PHOTOS Section: Image "BroomStick Antenna Tri-Band" GoTo= http://photos.groups.yahoo.com/group...FM-Antenna/lst iane ~ RHF .. .. = = = "Dave" = = = wrote in message ... "Telamon" wrote in message ... In article , "Dale Parfitt" wrote: "donutbandit" wrote in message ... "Dave" wrote in : I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. I built one. I was quite disappointed after reading all the hype. I get better reception from a wire run around the corners of my bedroom ceiling. I would not anticipate the broomstick antenna to be any different than a metal tube or rod of similar dimensions. Good comparison. A tightly wound broomstick would resemble a rod for receiving purposes. -- Telamon Ventura, California - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Still true, even if each turn of wire is insulated from those adjacent to it? How could that be? Thanks, Dave .. |
DAVE,
AHhhh, We Now Have More Information. An ATTIC Location and a Target Broadcaster Frequency (VOK). If your House/Building (The Attic) is positioned properly; and you have a specific band of Frequencies that you want to Receive. The you may wish to consider a simple Dipole Antenna for Directivity and relative Gain for a designed Frequency. "Using a 'SLINKY' as an Antenna ?" read Message #64 http://groups.yahoo.com/group/SWL-AM...nna/message/64 * Single SLINKY Vertical "Mono-Pole" ( The INVISABLE BroomStick Antenna ) * Dual SLINKY Horizontal "Dipole" http://groups.yahoo.com/group/SWL-AM...nna/message/66 Consider a commercial SLINKY Dipole Antenna in the Attic. http://groups.yahoo.com/group/SWL-AM...na/message/216 http://groups.yahoo.com/group/SWL-AM...na/message/254 iane ~ RHF .. .. = = = "Dave" = = = wrote in message ... - - - S N I P - - - Okay, so here's the problem. The fence is metal, and the house is covered with steel siding. My DX-402 does pick up BBC on 5975 pretty well with just the whip (next to a window), but VOK is extremely weak to vanishing. (This last one is what I want the broomstick antenna for.) If I do go with the broomstick, should I stick with the five-foot piece that I already have cut, or go with a longer eight-foot piece which will still fit nicely in the corner I have in mind. Or should I go all out with a ten-foot piece (or even multiples maybe) and put it in the attic? Also, what type of ground should I use? I could run a ground wire out the window to a ground rod that is as old as the house, but that's about my only option (the house predates three-prong plugs with a real ground.) I really appreciate your thoughts on these things. You obviously know a lot more about this stuff than I do. Thanks, Dave .. |
AV & DAVE,
FIRST: These are NOT Transmitting Antennas so the Metal Fence does NOT represent a 'potential' Hazard to your Transmitter. (Possible Direct Short Circuit to Ground.) "AV" - It's Not the Fence... Its the 200 Feet of Wire that makes up your Antenna Element. NOTE: With Metal Fences "Insulated" Wire seems to work better :o) Two Points of View for 'shorter' (20Ft-50Ft) Insulated Wire Antenna Elements that are mount "ON" or "THRU" Metal Fences: * Some people may tell you to run/route the Insulated Wire alone the "Top" of the Metal Fence. The Reasoning Being: The Wire is Higher in the Air and Off the Ground. (The Metal Fence will have less effect on the RF Signals being Received.) * Other people may tell you to run/route the Insulated Wire alone the "Middle" of the Metal Fence. (Half-Way between the Top and Bottom of the Fence.) The Reasoning Being: The Wire is in the Air and Off the Ground. (The Wire is being 'coupled' to the Metal Fence and the "Whole" Metal Fence has become the Antenna with a greater capture are to Receive RF Signals.) THIRD OPTION: "Above-the-Fence" Field SWL Antenna for a Field Radio. Recently I had the need to build a 'temporary' Low Noise SWL Antenna that was going to be 'mounted' ABOVE a Cyclone Fence. NOTE: The Fence was down the Hill about 75 Feet from the Deck of a Cabin. The Fence ran between a small Lake and a Cabin overlooking the Lake. * The Antenna Element was 100 Feet of Landscape Lighting Cable (Heavy Duty Outdoors Zip Cord). * The Fence was a Six Feet (6Ft) Tall Chain Line Fence. * I walked-off the fence with a note book and pencil. The Fence Sections (Poles) were 20 Ft apart. * When down to the hardware store and bought Six 10 Ft pieces of 1" PVC Pipe. * Also bought some plastic Locking Wire Ties. * Drilled a hole in one end of each of the PVC Pipes and installed a Wire Tie with a 2"-3" Open Loop. * Placed a piece of PVC Pipe next to each of the Metal Fence Poles. * * Attached a Guide Rope to the two end pieces of PVC Pipe. * Ran/Routed the Antenna Element through the Open Wire Tie Loops. * Affixed the two Feed-End wires of the Antenna Element across a TV 300 Ohm Matching Transformer (MT) and connected 100Ft of 75 Ohm Coax Cable to the other end of the MT. * * Attached a 12 Ft Ground Wire to the 75 Ohm Side of the MT. * At the Far-End of the Antenna Element; stripped and twisted together the two wires and covered them with electrical tape. * Place the Far-End PVC Pipe in the Vertical Position and used two Wire Ties to one at the Bottom of the fence and one at the top of the fence to hold it in place. Plus used the Guide Rope to Counter the Force of the Antenna Element. * Next placed the four middle pieces of PVC Pipe in the Vertical Position and used two Wire Ties to one at the Bottom of the fence and one at the top of the fence to hold it in place. * Then the Feed-End PVC Pipe in the Vertical Position and used two Wire Ties to one at the Bottom of the fence and one at the top of the fence to hold it in place. Plus used the Guide Rope to Counter the Force of the Antenna Element. * Attached the other end of the Ground Wire to the Metal Fence Post with a Large Hose Clamp at ground level; at the base of the Metal Fence Post and the in-the-ground Cement Anchor (2Ft-3Ft). * Ran/routed the Coax Cable from the the Antenna Element to the Receivers location on a Deck. Used a second grounding point directly under the deck at one of the Metal Pier Anchors. * Terminate the Coax Cable with an "F" Connector to PL-259 Plug Adapter for connection to the Receivers LO-Z (50 Ohm) SO-239 Jack. Or, use a second MT and Connect the 300 Ohm Output Leads to the Receiver's HI-Z (500 Ohm) Terminals. TBL: The Antenna Element is a "Flat-Thin-Loop" that is Physically 100 Ft Long and Electrically 200 Ft Out-and-Back. iane ~ RHF .. .. = = = AV = = = wrote in message ... Dave wrote: It is a metal fence. Chain-link. I didn't think that was a very likely answer to my problems. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I'd be curious as to why running a wire along a metal fence would be such a problem. I just ran about 200 feet of wire along the top of a wire fence (2 inch square openings), albeit the type that is covered with some green vinyl. And I have noticed CONSIDERABLE improvement in reception. Wouldn't attaching to so much metal just help to expand the range of the antenna ? Also, related to the metal fence thing: what would happen were I to attach a wire to my metal roof? And as long as we're on the subject of random wire, what's the deal with needing "stranded" wire. I had about 100 feet of that first, and then when I went to buy some more all they had was single strand, so I bought that and just added that to the end of the stranded. what's the importance/need of using stranded? av .. |
In article ,
"Dave" wrote: "Telamon" wrote in message ... In article , "Dale Parfitt" wrote: "donutbandit" wrote in message ... "Dave" wrote in : I just got through picking up a ton of discontinued wire from my local Home Depot, and was planning on building a "broomstick" antenna like some I found described on the net. I built one. I was quite disappointed after reading all the hype. I get better reception from a wire run around the corners of my bedroom ceiling. I would not anticipate the broomstick antenna to be any different than a metal tube or rod of similar dimensions. Good comparison. A tightly wound broomstick would resemble a rod for receiving purposes. -- Telamon Ventura, California Still true, even if each turn of wire is insulated from those adjacent to it? How could that be? At RF frequencies the coils are shorted electrically because there is a lot of capacitance between them. It won't work much better than a piece of metal the same size. Coils can be useful as part of an antenna if the turns are farther apart but as an element to pick up RF energy from the air medium it will work poorly. -- Telamon Ventura, California |
Still true, even if each turn of wire is insulated from those adjacent to it? How could that be? Thanks, Dave Telamon's explaination is spot on. The end of an antenna is high impedance- coils at the far end do not behave as inductors, rather as capacitors- thus the analogy to a solid tube. If the coil is placed, at a current point of an antenna (eg. near the center of a half wave) then it behaves as a pure inductor. Dale W4OP |
TELAMON,
"Tri-Band BroomStick Antenna" Read Message #410 GoTo= http://groups.yahoo.com/group/SWL-AM...na/message/410 * Eight Foot piece of 1.25" ID (1.5" OD) PVC Pipe * Seventy Feet (70 Ft) of #14 AWG Insulated Wire (19 Strands) * Top Hat ("9-12" Pie Pan) * Separator Stub 4" * Top Coil: 32 Turns @ 1/8" Spacing * Separator Stub 18" * Middle Coil: 52 Turns @ 1/4" Spacing * Separator Stub 11" * Bottom Coil: 82 Turns @ 1/2" Spacing * Separator Stub 6" * Lead-In-Line Connection "Image of Tri-Band 'BroomStick' Antenna" GoTo= http://groups.yahoo.com/group/SWL-AM...na/message/412 PHOTOS Section: Image "BroomStick Antenna Tri-Band" GoTo= http://photos.groups.yahoo.com/group...FM-Antenna/lst iane ~ RHF .. .. = = = Telamon = = = wrote in message ... - - - S N I P - - - At RF frequencies the coils are shorted electrically because there is a lot of capacitance between them. It won't work much better than a piece of metal the same size. Coils can be useful as part of an antenna if the turns are farther apart but as an element to pick up RF energy from the air medium it will work poorly. .. |
"Telamon" wrote in message ... At RF frequencies the coils are shorted electrically because there is a lot of capacitance between them. It won't work much better than a piece of metal the same size. Coils can be useful as part of an antenna if the turns are farther apart but as an element to pick up RF energy from the air medium it will work poorly. -- Telamon Ventura, California I have a little trouble with this statement. If there is so much capacitance between turns that you have an effective short, then things like IF transformers and AM loopstick antennas can't possibly work. A loading coil at the base of a whip antenna is no more useful than a chunk of metal? It just doesn't make sense. Coils are added to antennas to increase their effective length. If they just acted like a solid piece of metal they couldn't do that. craigm |
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CraigM,
1. If you look at many Transmitter Loading Coils. They are often Bare Wire with Insulated "Spacers" that provide an Air Gap. One of the "Features" of this 'design' is to Allow for HEAT (Power) Dispensation. 2. Many Up-In-The-Air Antennas use "Loading Coils" that are simply made of the same Insulated Wire or Bare Wire used in the Antenna. Frequently there is a 'small' Air Gap (about one to two wire diameters) in these Loading Coils. Sometimes when Insulated Wire is used these Loading Coils are simply wound with NO Air Gap. But remember, there is the Gap (Spacing) that is created by the Covering Insulation on both sides of the inner wire. Loading Coil Looks Like: iWiiWiiWiiWiiWiiWiiWiiWiiWiiWi "W" = Wire (Inner) "i" = Insultation (Outer) 3. For Shortwave "SWL" Antennas that are Receive ONLY. It is Simplier and Easier to use Insulated Wire and wrap the Loading Coils using the Side-By-Side wire wrapping method. NOTE: An 'alternative method' is to use a "De-Wired Insulated Wire" as a Spacer to create a Uniform Gap between the Loading Coil's wire coils. HOW TO: Estimate the length of the Wire required for the Loading Coil; and "Cut" a second piece of Insulated Wire to 'act' as a Spacer. Remove the 'inner wire' from the Insulation and use the Hollow Insulation (Tube) as a Spacer. 4. Cheap-and-Dirty "Loading Coil Form" = Simple and Easy to Make. Basically use common PVC Pipe: * 3/4" ID = 1" OD = Circumference 3.14" + Plus Factor in One #14 Insulated Wire Diameter (0.10") = Length of One-Turn-of-the-Coil would be 3.46" * 1.25" ID = 1.5" OD = Circumference 4.71" (Per Turn) + Plus Factor in One #14 Insualated Wire Diameter (0.10") = Length of One-Turn-of-the-Coil would be 5.02" HOW TO: Estimate the Lenght of your Loading Coil Winding Area. Add Two Inches (3/4" PVC Pipe) or Three Inches (1.25" PVC Pipe) to this for both PVC "End Caps" that will be used in the Form. * Cut the PVC Pipe to Length. * Glue on the End-Caps. * Drill a 1/4" Hole in the Ends of each of the End-Caps. [The End-Cap-Hole] * Drill a 1/4" Hole at the PVC Pipe right next to the Edge of each of the End-Caps. (Directly opposite each other.) [The Side-Hole] Use Black 1/4" Drip Irrigation Tubing (DIT) as a Strain Relief for the Antenna Wire / Loading Coil Wire. * Cut the DIT in to 4" pieces: * Use two pieces of DIT per Loading Coil. HOW TO: Building the Antenna "Loading Coil". * Feed the Antenna Wire through one piece of DIT. * Feed the Antenna Wire & DIT through the End-Cap-Hole and around to the Side-Hole. (About 2" out the End and 1/4" out the Side.) * Jam about 1" of the Hollow Insulation (Tube) that is being used as a Spacer into the Side-Hole. * Wrap the Loading Coil using the Antenna Wire and the Spacer as a Wire Pair. * Use Electrical Tape to 'temporarily' hold the Antenna Wire and Spacer in place on the PVC Pipe. * Feed the Antenna Wire through the other piece of DIT. * Feed the Antenna Wire & DIT through the other Side-Hole and around to the End-Cap-Hole. (About 2" out the End and 1/4" out the Side.) * Trim the Hollow Insulation (Tube) Spacer Free-End down to 1" and JAM that End into the other Side-Hole. * Use RTV Silicone to Seal the Side-Holes and End-Cap-Holes. NOTE: The "Remaining" Antenna Wire is routed to the Antenna's Far End (Terminating Insulator) -or- the next Loading Coil. OBTW: A copy of this Message has been posted to the YAHOO eGroup "SWL Antennas and AM & FM Antennas" - Read Message #421: * HOW-TO-BUILD: SWL Antenna Loading Coils - One Method http://groups.yahoo.com/group/SWL-AM...na/message/421 iane ~ RHF .. .. = = = "craigm" = = = wrote in message ... "Telamon" wrote in message news:telamon_spamshield- ... At RF frequencies the coils are shorted electrically because there is a lot of capacitance between them. It won't work much better than a piece of metal the same size. Coils can be useful as part of an antenna if the turns are farther apart but as an element to pick up RF energy from the air medium it will work poorly. -- Telamon Ventura, California - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I have a little trouble with this statement. If there is so much capacitance between turns that you have an effective short, then things like IF transformers and AM loopstick antennas can't possibly work. A loading coil at the base of a whip antenna is no more useful than a chunk of metal? It just doesn't make sense. Coils are added to antennas to increase their effective length. If they just acted like a solid piece of metal they couldn't do that. craigm .. |
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