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160M antenna for a very small garden?
Hi,
Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
OMG your garden is TINY. You will never be able to operate on top band
unless you get a vertical! I wish mine was 40*17ft. "M3" *** wrote in message news:4081ab53.0@entanet... Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
M3 wrote:
Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. A 1/2WL vertical should fit in a 40'x17' section. :-) -- 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! =----- |
"AM200" wrote in message ... OMG your garden is TINY. You will never be able to operate on top band unless you get a vertical! I wish mine was 40*17ft. A loop? |
Hi M3
Can you eke out 6 to 8 more feet somehow? Take a look at my linear loaded inverted Vee http://archimedes.galilei.com/raiar It has worked like gangbusters for me and for several others who have tried it also. TTUL Gary "M3" *** verbositized: Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
How about a top loaded vertical with every bit of that garden loaded with
radials??? Many of those longwave NDB's run antennas that are fairly small and they get out well. jw K9RZZ |
Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. ===================================== Hi, M3, The following set-up will work okay. Been there, done that. Height is the critical dimension. It will be about 2 S-units worse than ideal. Inverted-L antenna. Vertical section = 40 feet. Put a pole on house chimney to increase height. Horizontal section 40 feet. You can extend length at far end by making it an Inverted-U. A sytem of ground radials is essential. 8, 12, 16 shallow-buried radial wires at least 25 or 30 feet long in ordinary, damp garden soil. Important - connect the domestic plumbing pipes and incoming water main to the ground radial system. A tuner is essential. The average commercial tuner will NOT cope. You will need a home brew tuner. Wind some tapped coils on toilet roll tubes using 20 or 22 gauge wire. Inductance values up to 100 uH. See program SOLNOID3. Tuning capacitor = 500 pF maximum, 750 volts working, not particularly wide spaced plates. A LARGE old-fashioned receiving-type capacitor would be OK. Also obtain a few fixed-value, mica capacitors. Be prepared to experiment with tuning capacitor and coil values. If you like playing with a few numbers, download in a few seconds program ENDFEED from website below and run immediately. This program computes performance and also provides values of T-match and L-match components for given antenna wire dimensions. 160 meters, 50 miles groundwave in daylight with 100 watts. Transatlantic on CW, if you try hard, on long, very quiet, winter nights. It will be also be usable at high efficiency on higher frequency bands. For practical purposes, taking one band with another, it will be omni-directional. Get program ENDFEED from - .................................................. .......... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp .................................................. .......... |
How about the isotron antenna. take a look at:
www.rayfield.net/isotron "M3" *** wrote in message news:4081ab53.0@entanet... Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
K1SWR wrote:
How about the isotron antenna. take a look at: www.rayfield.net/isotron Sounds ideal, any one used/using one do they really work. I'm only looking to work local not really bothered with DX as such. Cheers all for your replies so far. |
M3 wrote:
K1SWR wrote: How about the isotron antenna. take a look at: www.rayfield.net/isotron Sounds ideal, any one used/using one do they really work. I'm only looking to work local not really bothered with DX as such. Save your money. An Isotron for 160m is simply a very bad idea. The best idea so far is a vertical, as tall as you can make it, with a radial system as extensive as you can make it, with a top hat as big as you can make it, matched at the base of 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! =----- |
Hi Brian
There are two legs, only one is shown as the other is identical to it. The closer you bring the ends the more directional the antenna becomes. I had my legs 80 feet apart on one system and only 25 feet apart on another system, both worked equally well, except the one with the smaller spread was considerably more directional. In my response I had asked if the poster could eke out another 6 to 8 feet, making that 17 feet dimension possibly 23 to 25 feet wide. Because at under 20 feet of spread, it begins to loose some functionality and noise levels increase exponentially. At least where mine was installed that is. I had tried all kinds of antennas for 160 in my small backyard and this one worked the best for me in my situation. Many others have used it, most with great success, but in some locations it worked worse than other designs they were using. When I moved the legs from the northern facing backyard to the southern facing front yard, the antenna did not work very well at all. Probably because of the many obstructions around it when situated in that direction. It's cheap, easy to assemble and try, if it doesn't work, you still have your two 130 feet sections of wire to try something else. TTUL Gary |
On Sun, 18 Apr 2004 15:45:13 +0100, "M3" *** wrote:
K1SWR wrote: How about the isotron antenna. take a look at: www.rayfield.net/isotron Sounds ideal, any one used/using one do they really work. I'm only looking to work local not really bothered with DX as such. Cheers all for your replies so far. I used an isotron 160 antenna for a short time. Working local stations it worked great but I was never able to work any DX. |
Gary V. Deutschmann, Sr. wrote:
I had my legs 80 feet apart ... Ouch! -----= 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! =----- |
Edward Lewis wrote:
I used an isotron 160 antenna for a short time. Working local stations it worked great but I was never able to work any DX. I'll bet most of your radiation was from your feedline. -- 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! =----- |
I'll bet most of your radiation was from your feedline.
-- 73, Cecil But it worked, didn't it! |
On Sun, 18 Apr 2004 17:54:39 +0000 (UTC), "Reg Edwards"
wrote: I'll bet most of your radiation was from your feedline. -- 73, Cecil But it worked, didn't it! Why doesn't someone write a book on radiating feedlines? They'd be a heck of a lot easier to put up than antennas :-) Bob k5qwg |
Reg Edwards wrote:
I'll bet most of your radiation was from your feedline. But it worked, didn't it! Pity the poor ham who puts an Isotron on a ten foot pole for field day. -- 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! =----- |
Bob Miller wrote:
Why doesn't someone write a book on radiating feedlines? They'd be a heck of a lot easier to put up than antennas :-) A 1/2WL dipole is an open-circuit radiating feedline complete with reflections. :-) From Balanis: "The current and voltage distributions on open-ended wire antennas are similar to the standing wave patterns on open-ended transmission lines." Wasn't the original Gap antenna simply a leaky transmission line? -- 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! =----- |
"Dave VanHorn" wrote in message ... "AM200" wrote in message ... OMG your garden is TINY. You will never be able to operate on top band unless you get a vertical! I wish mine was 40*17ft. A loop? A loop should be cut at approx. lambda/10, so with a circumference of 16m or a radius of 5m ! Too bulky for a small garden Thierry, ON4SKY http://www.astrosurf.com/lombry |
A loop should be cut at approx. lambda/10, so with a circumference of 16m
or a radius of 5m ! Too bulky for a small garden ============================== What prevents it being cut with a circumference LESS than 16m. --- Reg, G4FGQ |
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"Reg Edwards" wrote in message ... A loop should be cut at approx. lambda/10, so with a circumference of 16m or a radius of 5m ! Too bulky for a small garden ============================== What prevents it being cut with a circumference LESS than 16m. Indeed, there isn't anything on 160M that's going to NOT be a compromise here. |
Why not try a double layered loop? Feed with a 4:1 balun about 1/4 of
the way from the corner on the 40 ft side, make a spiral, and send the other side back to the balun. Separate the two layers by about 10 feet, get it at least 15 feet off the ground at the bottom, and it should work. In that small of a garden, you're going to have to compromise.. might as well get as much wire in the air as you can. -SSB M3 wrote: Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
sideband wrote in message . com...
Why not try a double layered loop? Feed with a 4:1 balun about 1/4 of the way from the corner on the 40 ft side, make a spiral, and send the other side back to the balun. Separate the two layers by about 10 feet, get it at least 15 feet off the ground at the bottom, and it should work. In that small of a garden, you're going to have to compromise.. might as well get as much wire in the air as you can. -SSB I don't think double layering will have much change, except for where it's resonant. It should still act pretty much the same as a single turn loop of that size. Myself, I think he would be best off going with a very high performance short vertical. A loop is gonna be a skywarmer, and a lukewarm one at best. I would layer the garden with almost solid metal, preferably copper wires, or whatever, and run the best, tallest, lowest loss vertical he could get away with. I'd top load it if at all possible. That will greatly improve the current distribution. With a good vertical, he would at least have a chance of having a decent signal. For long haul, nothing else he could install would touch it. I like the inv L idea, but I assume he can't do that for some reason. M3 wrote: Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. If you line that garden with a lot of radials under the ground, you could have acceptable losses for what you have to work with. Most loss is directly at the base of the vertical. Plant a lot of radials lining the garden, and you will do ok. MK |
There's something called an EH-antenna... despite many claims it is not a
wonder antenna, but it does get you on the air... it's not a substitute for a dipole or beam though (I saw a 160m 2 element quad.. that was a monster, but I digress). www.eh-antenna.com Somewhere I saw someone's test of one at some low band... 80 or 160m I forget which... It was pretty good sized, but tiny compared to say, a dipole. 2-3' in diameter, looked to be about 10-15' tall. no real good 'scale' photos. I have seen a couple of 'how to build' articles on the web, but don't have them handy I'm afraid. Unfortunately nothing is going to work really well... given your space limitations. I'd go for as much of a vertical as I could, and run ground radials in the garden, or maybe a ehem 'long' wire run around two sides of the property maybe? -- "M3" *** wrote in message news:4081ab53.0@entanet... Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
Cecil Moore wrote in message ...
Reg Edwards wrote: Pity the poor ham who puts an Isotron on a ten foot pole for field day. And the same pays for the EH antenna, see http://home.earthlink.net/~calvinf15...est_report.pdf 73 Ivan OK1SIP |
Also the EH antenna have to follow the laws of nature. The laws of nature is
inthing You can disobey, and get a few Years of prison. It is simply impossible! So, the EH antenna does not work according the way the inventors claim. Of course, it radiates. But: The main radiating element of a "good" EH antenna system is the feeder (koax) shield. Not the antenna itself. So, if You have a short feeder, the antenna will radiate very poor (however, it of course radiates). And the EH antenna is NOT CHEAP!. There are some other types og antennas: 1) The Isotron antenna, which is a Q-tank, thus radiates poorly as well, but the inventors to my knowledge does not make any un-scientifical claims. You can work some stations with it, it might be a "salvation" if You are real eager to get on 160, and does not want to do a massive work Yorself. 2) The magloop, an interesting but complex way to make a small antenna. It WORKS, efficiency is not good, but amazing results can be achieved! 3) DCTL, in fact a magloop, but is NOT recommended for 160. 4) A dipole made of 2 commercially bought mobile whips including coils: Works, efficiency is not good. 5) A mobile whip. It is small, and a built in small coil with low Q. Not my kind of tea. 6) Ultra-shortened ground plane aka monopole. A capacitive antenna, which can be used, if You have good nerves (HIGH VOLTAGE!) and a variometer. Look what the european 136kHz (LW) hams are achieving! I would recomment this type! (of COURSE low efficiency, but one can use hi-Q coils, which outperforms other set-ups) No type is GOOD for 160m if You have resticted space... Tyas_MT wrote: There's something called an EH-antenna... despite many claims it is not a wonder antenna, but it does get you on the air... it's not a substitute for a dipole or beam though (I saw a 160m 2 element quad.. that was a monster, but I digress). www.eh-antenna.com Somewhere I saw someone's test of one at some low band... 80 or 160m I forget which... It was pretty good sized, but tiny compared to say, a dipole. 2-3' in diameter, looked to be about 10-15' tall. no real good 'scale' photos. I have seen a couple of 'how to build' articles on the web, but don't have them handy I'm afraid. Unfortunately nothing is going to work really well... given your space limitations. I'd go for as much of a vertical as I could, and run ground radials in the garden, or maybe a ehem 'long' wire run around two sides of the property maybe? -- "M3" *** wrote in message news:4081ab53.0@entanet... Hi, Any designs for a small antenna to work on 160M? My garden is approx 40ft x 17ft. Post links here. Thanks. |
M3 wrote:
"Any designs for a small antenna to work on 160M ?" Small antennas are inefficient. Medium wave broadcast stations have operated from small plots with some satisfaction. They once commonly operated from building tops in the middle of the city. Building top antenna systems were most often short verticals worked against a ground plane. The broadcaster only wanted vertically polarized radiation, radiated at an extremely low angle. DXers want low-angle radiation too, but not 0-degree radiation. A horizontal wire must be 1/2-wave high for low-angle radiation; more if conductivity is good under the antenna. The shortest vertical antenna with a groundplane has a null in its radiation pattern directly overhead but most radiation is at low angles. The efficiency of a vertical antenna over real earth is bad without an excellent ground system. U.S. medium-wave broadcasters approach 100% efficiency using 1/4-wave towers and 120 radials near the earth`s surface. As antenna efficiency is: radiation resistance divided by the sum of radiation resistance plus loss resistance, the short vertical antenna (whip) has a low radiation resistance and poor efficiency. The efficiency formula has a small numerator, thus a small quotient. As most mobile operators have found, the short vertical antenna is not the best choice. It is the only choice for an extremely restricted space. How can the best use be made of a small garden space? Jerry Sevick, W2FMI is pictured adjusting his 6-foot high 40-meter vertical on page 6-24 of my 19th edition of the ARRL Antenna Book. There are several other options in chapter 6 of the "Antenna Book". Get it or a similar book and study applicabilities to your situation. Antennas scale to most wavelengths. Best regards, Richard Harrison, KB5WZI |
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