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#1
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Hi,
Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly? I have to put it into two trees to get height. Are there any good links or sights to learn proper making and installation? Thanks. |
#2
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Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly Hammer, An all band dipole should not be fed with coax. On many of the bands you want to work, the coax will have too much loss, and may fail due to the extreme voltages that may be present. A better choice would be a dipole, as long and high as you can make it. Feed it with 450 ohm ladder line to an antenna tuner in your shack. The 1:1 balun should insert between the line and your tuner. You now have an all band efficient dipole. BTW the antenna newsgroup would be better to ask this type of question, you will get loads of answers there. 73 Gary N4AST |
#3
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Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of
wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly Hammer, An all band dipole should not be fed with coax. On many of the bands you want to work, the coax will have too much loss, and may fail due to the extreme voltages that may be present. A better choice would be a dipole, as long and high as you can make it. Feed it with 450 ohm ladder line to an antenna tuner in your shack. The 1:1 balun should insert between the line and your tuner. You now have an all band efficient dipole. BTW the antenna newsgroup would be better to ask this type of question, you will get loads of answers there. 73 Gary N4AST |
#4
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Hammer wrote:
Hi, Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly? I have to put it into two trees to get height. Are there any good links or sights to learn proper making and installation? A lot depends on how much space you have. A straight dipole with a 1:1 balun and coax will only cover one band. Well, maybe two if you cut it for 40 meters. (it'll then work OK on 15 as well) You have a few other options: - Make the dipole as long as possible (the exact length is unimportant); don't use the balun; use ladder line instead of coax; and connect it to a tuner in the shack. - Run several dipoles in parallel. 132' for 80m, 66' for 40m, 33' for 20m, etc. They can all share the same balun and coax. - Trade the 1:1 balun for a 4:1 and put up an off-center-fed dipole. A 132' antenna, with 44' on one side and 88' on the other, will work well on every band between 80 and 10 with the exception of 15. (and it's close enough on 15 that if your rig has an autotuner, it'll work there too) I've got the latter antenna. It's the most "bang for the buck" in my antenna collection. (it even works halfway decent for DXing the AM broadcast band!) A good general rule for wire antennas is as high as possible, as straight as possible, and as far from obstructions as possible. And don't sweat it if "as far as possible" isn't very far. (UNLESS the obstruction is a power line!) -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
#5
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Hammer wrote:
Hi, Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly? I have to put it into two trees to get height. Are there any good links or sights to learn proper making and installation? A lot depends on how much space you have. A straight dipole with a 1:1 balun and coax will only cover one band. Well, maybe two if you cut it for 40 meters. (it'll then work OK on 15 as well) You have a few other options: - Make the dipole as long as possible (the exact length is unimportant); don't use the balun; use ladder line instead of coax; and connect it to a tuner in the shack. - Run several dipoles in parallel. 132' for 80m, 66' for 40m, 33' for 20m, etc. They can all share the same balun and coax. - Trade the 1:1 balun for a 4:1 and put up an off-center-fed dipole. A 132' antenna, with 44' on one side and 88' on the other, will work well on every band between 80 and 10 with the exception of 15. (and it's close enough on 15 that if your rig has an autotuner, it'll work there too) I've got the latter antenna. It's the most "bang for the buck" in my antenna collection. (it even works halfway decent for DXing the AM broadcast band!) A good general rule for wire antennas is as high as possible, as straight as possible, and as far from obstructions as possible. And don't sweat it if "as far as possible" isn't very far. (UNLESS the obstruction is a power line!) -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
#6
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![]() "Hammer" wrote in message ... Hi, Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly? I have to put it into two trees to get height. Are there any good links or sights to learn proper making and installation? Thanks. A standard dipole will only work well on one band. However, if you put several different dipoles together in parallel, you can have antennas for different bands using the same feedpoint. Check out: http://www.geocities.com/n2uhc/2banddipole.com for more information. I use a combination 20/40 meter dipole for portable operation with my QRP rigs. Just keep in mind that the different elements for different bands will interact with each other. If this weren't the case it would be feasable to put elements for 80-10 together and use the same feedpoint. Since they do interact, you may want to put together what's known as a fan dipole, where the different elements are angled away from each other to cut down on the interaction. -- Tom Sevart N2UHC Frontenac, KS http://www.geocities.com/n2uhc |
#7
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![]() "Hammer" wrote in message ... Hi, Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly? I have to put it into two trees to get height. Are there any good links or sights to learn proper making and installation? Thanks. A standard dipole will only work well on one band. However, if you put several different dipoles together in parallel, you can have antennas for different bands using the same feedpoint. Check out: http://www.geocities.com/n2uhc/2banddipole.com for more information. I use a combination 20/40 meter dipole for portable operation with my QRP rigs. Just keep in mind that the different elements for different bands will interact with each other. If this weren't the case it would be feasable to put elements for 80-10 together and use the same feedpoint. Since they do interact, you may want to put together what's known as a fan dipole, where the different elements are angled away from each other to cut down on the interaction. -- Tom Sevart N2UHC Frontenac, KS http://www.geocities.com/n2uhc |
#8
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A standard dipole will only work well on one band. However, if you put
several different dipoles together in parallel, you can have antennas for different bands using the same feedpoint. ========================== A single dipole will work well on many bands ,provided a balanced feeder of 300 - 450 or 600 Ohms (to name a few) is used ,obviously with a balanced to unbalanced matching unit. For this purpose I successfully use a 2 times 21 metres (68 ft) dipole with a 450 Ohms ribbon feeder on all bands from 1.8 to 30 MHz. The length is not all that critical although the dipole should preferably be half a wavelength for the lower freq band used. Because of its balanced behaviour the feeder does not radiate . In my case the feeder runs into and over the loft into the lower level shack without RF interference problems . Frank GM0CSZ / KN6WH |
#9
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A standard dipole will only work well on one band. However, if you put
several different dipoles together in parallel, you can have antennas for different bands using the same feedpoint. ========================== A single dipole will work well on many bands ,provided a balanced feeder of 300 - 450 or 600 Ohms (to name a few) is used ,obviously with a balanced to unbalanced matching unit. For this purpose I successfully use a 2 times 21 metres (68 ft) dipole with a 450 Ohms ribbon feeder on all bands from 1.8 to 30 MHz. The length is not all that critical although the dipole should preferably be half a wavelength for the lower freq band used. Because of its balanced behaviour the feeder does not radiate . In my case the feeder runs into and over the loft into the lower level shack without RF interference problems . Frank GM0CSZ / KN6WH |
#10
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On Sat, 7 Feb 2004 12:45:29 -0500, "Hammer"
wrote: Hi, Putting up a 10 through 160 or 10 through 80 meters dipole. I have lots of wire and coax and a 1:1 balon. Interested in how the shape or form of this dipole should be to work properly? I have to put it into two trees to get height. Are there any good links or sights to learn proper making and installation? Thanks. To keep things simple and multi-band I would suggest you try to feed your dipole with open wire feeder and use a balanced tuner. You won't need that balun. I have been doing that with a dipole cut for 80m and it tunes well on ALL bands (even 160, but is not that great on that band!) and works effectively for me. Of course you will get different radiation patterns on each band - but it works and if you have a good tuner it can be a very efficient antenna for QRP. I have tried using multi-leg dipoles, G5RV's and trapped dipoles for different bands but they are harder to set-up and simply did not work as well for me. I believe your easiest multi-band option is what I mentioned above. You can even make your own open-wire feeders for next to nothing and have a much longer, less lossy feedline than you would get with RG8 coax, especially on 10metres. Get the dipole up as high as possible. It really is very simple and effective. Larry Gagnon VE7EA *************** remove "fake" from email address |
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