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#11
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hi there..
think i will put my pennys worth in here... do away with the long wire altogether..you will proberly never get rid of the rf in shack etc..due to being too high above gnd..i know i have tried..i live in an apartment (3rd floor)..no garden or land..i have tried end feed long wire from balcony to lamp post etc..rfi to phones stereo etc..BAD i tried all the tricks in the book no go... SO.. i chatted my neighboors up and have been using successfully for 4 years now a full sized 10m-80m diople (trapped with 40m trapps.)its slung up at 3 points in the shape of a triangle each courner on someone elses apartment..the coax feed is rolled up 6 times 6inches dia just before diople feed point..i have hung seperate dioples for 18mhz.28mz below main diople to help on those bands .. i have had NO tvi/stereo i/ phone i etc atall (touch wood)..i am using full size diople but not out straight so you could too, espically as you have a garden!!! and have worked much dx all over the world with 100w ssb... so if you give up with the long wire (as i did) try this..its cheap too..and the antenna is in about every antenna handbook..) simon g0zen "Cecil Moore" wrote in message ... Vaughn Combs wrote: Any ideas would be GREATLY appreciated. To effectively avoid RF in the shack, the differential currents need to be balanced (equal in magnitude and 180 degrees out of phase). It is extremely difficult to do that with an inv-L. I had good luck with a dipole even though the shack was under one end of the dipole. I brought the ladder-line off at right angles for about 50 ft then routed ladder-line back to the shack from there so ladder-line parallel to the antenna was always about 50 ft away from the antenna. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#12
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Always begin with the most simple of antennas. Otherwise you'll have
nothing to make comparisons with. You will have no base or foundation standard. Spend a couple of hours stringing up a 150 feet inverted-L and use it on all bands for a few weeks. That is if you can wrench youself away from it. ---- Reg, G4FGQ |
#13
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Always begin with the most simple of antennas. Otherwise you'll have
nothing to make comparisons with. You will have no base or foundation standard. Spend a couple of hours stringing up a 150 feet inverted-L and use it on all bands for a few weeks. That is if you can wrench youself away from it. ---- Reg, G4FGQ |
#14
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Vaughn,
It's quite easy: your best bet is the maximum length of wire you can keep in your backyard AND as high up in the air as you can afford (trees, towers, chimneys etc.) To prevent RFI and TVI, make your antenna symmetrical. Feed it with an open line, and connect the open line with your TX with an appropriate coupler (the ARRL Handbook is a good source for information). Please note you do not need to use a thick gauge of copper wire. Even a thin gauge of stainless steel wire will do. You will be pleased very much by the results !! 73 de PA0ARY On Sat, 03 Jan 2004 18:38:59 +0000, Vaughn Combs wrote: I have a few questions and I thought that this may be the group that could help. I have a nice sized backyard and would like to construct an antenna that would give me good performance on 80-10m bands. The convenient dimensions would put a support (far end) at either 92 feet from the back of the house (support exists that is about 15-20 feet up) or 120 feet from the back of the house (mast anchored to the other side of a shed could easily be installed. Or a more inconvenient support could be erected up to 300 feet out (no support buildings) at the absolute far end of the property. The width of the property as seen looking out the back window is about 65 feet (no supports existing on either side). Special circumstances and constraints: -- No tall trees on the property. -- Attic shack (attic window is probably about 25 feet up). Need to keep to the attic. -- Cable run from back of house to operating position within the attic would be approximately 25 feet -- MUST eliminate RFI in the shack and house. My current setup is an end-fed longwire that works well on all bands except 40m (rig shuts down as I am dipping the SWR to almost 1:1 ;-). I threw up the wire as winter was upon me. I have been off the air for almost 10 years and REALLY wanted to get on the air again. While the longwire is performing quite well with the exception of 40m I am getting a ton of RF in the shack and it is blanking out TVs and creating loud humming in speakers with 100W from the XMTR. I realize that this is most likely due to the fact that I have inefficient RF ground and I have cut and run radial at 1/4 wave for each band and ran them under the eaves up here in the attic. This has not solved the problem. I am friendly with all of my neighbors and have visited them and did testing on the bands with them on the phone. They are not experiencing any problems. My wife, while understanding, would REALLY like the problem to go away ;-) My main goal is to build an antenna that will solve the aforementioned RFI problem and that will provide good performance given my constraints. Any ideas would be GREATLY appreciated. Many Thanks and 73, Vaughn N2BHA |
#15
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ary wrote:
It's quite easy: your best bet is the maximum length of wire you can keep in your backyard AND as high up in the air as you can afford (trees, towers, chimneys etc.) Hmmmmm, my back yard is ten acres. :-) -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#16
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"ary" wrote in message
news ![]() Vaughn, It's quite easy: your best bet is the maximum length of wire you can keep in your backyard AND as high up in the air as you can afford (trees, towers, chimneys etc.) To prevent RFI and TVI, make your antenna symmetrical. Feed it with an open line, and connect the open line with your TX with an appropriate coupler (the ARRL Handbook is a good source for information). Hi, All depends. I already underligned 2 big mistakes about SWR and ground screen. All is relative you know Please note you do not need to use a thick gauge of copper wire. Even a thin gauge of stainless steel wire will do. I call this a G5RV... ;-) Thierry ON4SKY http://www.astrosurf.com/lombry/qsl-g5rv.htm You will be pleased very much by the results !! 73 de PA0ARY On Sat, 03 Jan 2004 18:38:59 +0000, Vaughn Combs wrote: I have a few questions and I thought that this may be the group that could help. I have a nice sized backyard and would like to construct an antenna that would give me good performance on 80-10m bands. The convenient dimensions would put a support (far end) at either 92 feet from the back of the house (support exists that is about 15-20 feet up) or 120 feet from the back of the house (mast anchored to the other side of a shed could easily be installed. Or a more inconvenient support could be erected up to 300 feet out (no support buildings) at the absolute far end of the property. The width of the property as seen looking out the back window is about 65 feet (no supports existing on either side). Special circumstances and constraints: -- No tall trees on the property. -- Attic shack (attic window is probably about 25 feet up). Need to keep to the attic. -- Cable run from back of house to operating position within the attic would be approximately 25 feet -- MUST eliminate RFI in the shack and house. My current setup is an end-fed longwire that works well on all bands except 40m (rig shuts down as I am dipping the SWR to almost 1:1 ;-). I threw up the wire as winter was upon me. I have been off the air for almost 10 years and REALLY wanted to get on the air again. While the longwire is performing quite well with the exception of 40m I am getting a ton of RF in the shack and it is blanking out TVs and creating loud humming in speakers with 100W from the XMTR. I realize that this is most likely due to the fact that I have inefficient RF ground and I have cut and run radial at 1/4 wave for each band and ran them under the eaves up here in the attic. This has not solved the problem. I am friendly with all of my neighbors and have visited them and did testing on the bands with them on the phone. They are not experiencing any problems. My wife, while understanding, would REALLY like the problem to go away ;-) My main goal is to build an antenna that will solve the aforementioned RFI problem and that will provide good performance given my constraints. Any ideas would be GREATLY appreciated. Many Thanks and 73, Vaughn N2BHA |
#17
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It's quite easy: your best bet is the maximum length of wire you can keep
in your backyard AND as high up in the air as you can afford (trees, towers, chimneys etc.) Hmmmmm, my back yard is ten acres. :-) Until wind toppled the tree at one end, my "dipole" went 275 feet SW and 250 feet NE of the "center" feed point. Height was about 45 feet. Someone once commented that the reason I "got out" so well was that, by the time the RF reached the end of my antenna, it was already a significant part of the distance toward its destination!-) --Myron. -- Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448 NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol) |
#18
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The best antenna is not the longest thing you can put up, unless one of the
many minor lobes you create will point exactly where you want to go at a radiation angle you need, and this is highly unlikely, but it does sometimes happen. The best thing to do is decide where you'd like to reach, for example, which continent. Are you a DXer or do you do mostly local rag chews? What frequency bands would you like to operate, and what size constraints do you have to live with? Are there any natural supports you'd like to take advantage of? Do you need multiband operation? Do you have an deed restrictions on what you can put up? Study the radiation patterns of dipoles, verticals and if you have the space, long wires. Do you have a tuner? Remember, no antenna creates RF to get "gain", they only focus it. The ideal RF antenna would radiate equally well in all directions. Since you live on earth, the effect of height is an issue, as is the ground effect on the pattern. The best antenna to start with for a newbie is a windom cut for the lowest band that will fit on your lot. With this kind of antenna you can run all harmonic bands (ie 80M will cover 40M,20M,10M while 40M will cover 40M, 20M, 10M) quite well and not require a tuner. Several of the WARC bands will work ok too but the SWR may be a little higher. I regularly use my 80M windom on all bands here, most of them without a tuner, and the rigs tuner is good enough on the one or two where the SWR is just over 2:1 which isn't an issue, it just causes the radio to reduce power. The second best antenna is a vertical, but most newbies screw up the installation. You either need 4 elevated radials or you need lots of radials on the ground. Lots means 16 or more. Again, the literature is full of information on these topics, and there was even an article a few months ago in QST I think where someone did a study on the best use of the wire for a vertical ground plan - ie more or longer radials for a given length of wire to optimize results. The vertical is a good newbie antenna because it radiates equally well (some say equally poorly) in all directions. Although some of that will go to places where no one lives, if you have a good ground plane the low angle of radiation will be to your advantage. One caution, if you live with a lot of neighbors around verticals pick up noise more than horizontal antennas and this can be a big issue. In that case stick with a windom. If you have the money and the time and a computer, try purchasing an antenna modeling software packet. I use NEC4WIN but there are many. With this, you can model various wire configurations quickly and see EXACTLY what they will do in terms of gain/loss/pattern etc. This will save you a lot of time and money building things that don't work. Finally, if your interest is local ragchewing, a low horizontal antenna may be just fine. I have an extensive antenna farm here, quads, yagis, dipoles, verticals, etc. and over the past 35 years I've tried everything. The best overall antenna, the one that I keep coming back to as a standard or default for comparison is the windom. This off center fed device is fed at a point where the SWR is tolerable on harmonically related bands using a matching balun. My favorite was made by Fritzel, but I don't think they make them anymore, but an internet search will turn up several suppliers and/or plans for your own. The biggest issue in a windom is just the balun, and I recommend CWS Bytemark products if you can get them. Again though, remember that once the lengh of the wire is greater than 1/2 wavelengh the pattern starts to form lobes that can give you a great signal - somewhere - and an equally poor signal in other places. This is true for a windom too, on its harmonic bands. That is why 40 meter windoms exist (besides the fact that they are shorter). One of the best ways to solve your problem is by reading. Fortunately these days you can read about antennas for hours on the internet at no cost, but the best books I've found over the years are the ARRL Anthology series and of course the ARRL antenna book. 73, WT6G PS Do not waste your time and reply to this email address. It won't work. "ary" wrote in message news ![]() Vaughn, It's quite easy: your best bet is the maximum length of wire you can keep in your backyard AND as high up in the air as you can afford (trees, towers, chimneys etc.) To prevent RFI and TVI, make your antenna symmetrical. Feed it with an open line, and connect the open line with your TX with an appropriate coupler (the ARRL Handbook is a good source for information). Please note you do not need to use a thick gauge of copper wire. Even a thin gauge of stainless steel wire will do. You will be pleased very much by the results !! 73 de PA0ARY On Sat, 03 Jan 2004 18:38:59 +0000, Vaughn Combs wrote: I have a few questions and I thought that this may be the group that could help. I have a nice sized backyard and would like to construct an antenna that would give me good performance on 80-10m bands. The convenient dimensions would put a support (far end) at either 92 feet from the back of the house (support exists that is about 15-20 feet up) or 120 feet from the back of the house (mast anchored to the other side of a shed could easily be installed. Or a more inconvenient support could be erected up to 300 feet out (no support buildings) at the absolute far end of the property. The width of the property as seen looking out the back window is about 65 feet (no supports existing on either side). Special circumstances and constraints: -- No tall trees on the property. -- Attic shack (attic window is probably about 25 feet up). Need to keep to the attic. -- Cable run from back of house to operating position within the attic would be approximately 25 feet -- MUST eliminate RFI in the shack and house. My current setup is an end-fed longwire that works well on all bands except 40m (rig shuts down as I am dipping the SWR to almost 1:1 ;-). I threw up the wire as winter was upon me. I have been off the air for almost 10 years and REALLY wanted to get on the air again. While the longwire is performing quite well with the exception of 40m I am getting a ton of RF in the shack and it is blanking out TVs and creating loud humming in speakers with 100W from the XMTR. I realize that this is most likely due to the fact that I have inefficient RF ground and I have cut and run radial at 1/4 wave for each band and ran them under the eaves up here in the attic. This has not solved the problem. I am friendly with all of my neighbors and have visited them and did testing on the bands with them on the phone. They are not experiencing any problems. My wife, while understanding, would REALLY like the problem to go away ;-) My main goal is to build an antenna that will solve the aforementioned RFI problem and that will provide good performance given my constraints. Any ideas would be GREATLY appreciated. Many Thanks and 73, Vaughn N2BHA -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#19
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The best antenna is not the longest thing you can put up, unless one of the
many minor lobes you create will point exactly where you want to go at a radiation angle you need, and this is highly unlikely, but it does sometimes happen. The best thing to do is decide where you'd like to reach, for example, which continent. Are you a DXer or do you do mostly local rag chews? What frequency bands would you like to operate, and what size constraints do you have to live with? Are there any natural supports you'd like to take advantage of? Do you need multiband operation? Do you have an deed restrictions on what you can put up? Study the radiation patterns of dipoles, verticals and if you have the space, long wires. Do you have a tuner? Remember, no antenna creates RF to get "gain", they only focus it. The ideal RF antenna would radiate equally well in all directions. Since you live on earth, the effect of height is an issue, as is the ground effect on the pattern. The best antenna to start with for a newbie is a windom cut for the lowest band that will fit on your lot. With this kind of antenna you can run all harmonic bands (ie 80M will cover 40M,20M,10M while 40M will cover 40M, 20M, 10M) quite well and not require a tuner. Several of the WARC bands will work ok too but the SWR may be a little higher. I regularly use my 80M windom on all bands here, most of them without a tuner, and the rigs tuner is good enough on the one or two where the SWR is just over 2:1 which isn't an issue, it just causes the radio to reduce power. The second best antenna is a vertical, but most newbies screw up the installation. You either need 4 elevated radials or you need lots of radials on the ground. Lots means 16 or more. Again, the literature is full of information on these topics, and there was even an article a few months ago in QST I think where someone did a study on the best use of the wire for a vertical ground plan - ie more or longer radials for a given length of wire to optimize results. The vertical is a good newbie antenna because it radiates equally well (some say equally poorly) in all directions. Although some of that will go to places where no one lives, if you have a good ground plane the low angle of radiation will be to your advantage. One caution, if you live with a lot of neighbors around verticals pick up noise more than horizontal antennas and this can be a big issue. In that case stick with a windom. If you have the money and the time and a computer, try purchasing an antenna modeling software packet. I use NEC4WIN but there are many. With this, you can model various wire configurations quickly and see EXACTLY what they will do in terms of gain/loss/pattern etc. This will save you a lot of time and money building things that don't work. Finally, if your interest is local ragchewing, a low horizontal antenna may be just fine. I have an extensive antenna farm here, quads, yagis, dipoles, verticals, etc. and over the past 35 years I've tried everything. The best overall antenna, the one that I keep coming back to as a standard or default for comparison is the windom. This off center fed device is fed at a point where the SWR is tolerable on harmonically related bands using a matching balun. My favorite was made by Fritzel, but I don't think they make them anymore, but an internet search will turn up several suppliers and/or plans for your own. The biggest issue in a windom is just the balun, and I recommend CWS Bytemark products if you can get them. Again though, remember that once the lengh of the wire is greater than 1/2 wavelengh the pattern starts to form lobes that can give you a great signal - somewhere - and an equally poor signal in other places. This is true for a windom too, on its harmonic bands. That is why 40 meter windoms exist (besides the fact that they are shorter). One of the best ways to solve your problem is by reading. Fortunately these days you can read about antennas for hours on the internet at no cost, but the best books I've found over the years are the ARRL Anthology series and of course the ARRL antenna book. 73, WT6G PS Do not waste your time and reply to this email address. It won't work. "ary" wrote in message news ![]() Vaughn, It's quite easy: your best bet is the maximum length of wire you can keep in your backyard AND as high up in the air as you can afford (trees, towers, chimneys etc.) To prevent RFI and TVI, make your antenna symmetrical. Feed it with an open line, and connect the open line with your TX with an appropriate coupler (the ARRL Handbook is a good source for information). Please note you do not need to use a thick gauge of copper wire. Even a thin gauge of stainless steel wire will do. You will be pleased very much by the results !! 73 de PA0ARY On Sat, 03 Jan 2004 18:38:59 +0000, Vaughn Combs wrote: I have a few questions and I thought that this may be the group that could help. I have a nice sized backyard and would like to construct an antenna that would give me good performance on 80-10m bands. The convenient dimensions would put a support (far end) at either 92 feet from the back of the house (support exists that is about 15-20 feet up) or 120 feet from the back of the house (mast anchored to the other side of a shed could easily be installed. Or a more inconvenient support could be erected up to 300 feet out (no support buildings) at the absolute far end of the property. The width of the property as seen looking out the back window is about 65 feet (no supports existing on either side). Special circumstances and constraints: -- No tall trees on the property. -- Attic shack (attic window is probably about 25 feet up). Need to keep to the attic. -- Cable run from back of house to operating position within the attic would be approximately 25 feet -- MUST eliminate RFI in the shack and house. My current setup is an end-fed longwire that works well on all bands except 40m (rig shuts down as I am dipping the SWR to almost 1:1 ;-). I threw up the wire as winter was upon me. I have been off the air for almost 10 years and REALLY wanted to get on the air again. While the longwire is performing quite well with the exception of 40m I am getting a ton of RF in the shack and it is blanking out TVs and creating loud humming in speakers with 100W from the XMTR. I realize that this is most likely due to the fact that I have inefficient RF ground and I have cut and run radial at 1/4 wave for each band and ran them under the eaves up here in the attic. This has not solved the problem. I am friendly with all of my neighbors and have visited them and did testing on the bands with them on the phone. They are not experiencing any problems. My wife, while understanding, would REALLY like the problem to go away ;-) My main goal is to build an antenna that will solve the aforementioned RFI problem and that will provide good performance given my constraints. Any ideas would be GREATLY appreciated. Many Thanks and 73, Vaughn N2BHA -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
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