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#1
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E H Antenna
Just heard mention of the EH Antenna and that it is rather small but equal
radiation to a full size dipole !!!. If this is true, i am very interested as i only have a small garden (35x18 feet) and the EH sounds ideal so anyone with info , it would be greatly appreciated. I am using a homebrew helical for 80m and a sloping half size G5RV and i am really stuck for space :-/ Lee.....G6ZSG.. |
#2
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Was interested too, but gave up. With so many different descriptions for one
concept, there must bee something foolish. And I don't want to use my rig as an antenna! 73 de F8BOE Olivier ...-.- Lee wrote: Just heard mention of the EH Antenna and that it is rather small but equal radiation to a full size dipole !!!. If this is true, i am very interested as i only have a small garden (35x18 feet) and the EH sounds ideal so anyone with info , it would be greatly appreciated. I am using a homebrew helical for 80m and a sloping half size G5RV and i am really stuck for space :-/ Lee.....G6ZSG.. |
#3
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Just heard mention of the EH Antenna and that it is rather small
but equal radiation to a full size dipole !!!. =========================== Sucker! If you believe that then you'll believe anything. |
#4
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"Reg Edwards" wrote in message ... Just heard mention of the EH Antenna and that it is rather small but equal radiation to a full size dipole !!!. =========================== Sucker! If you believe that then you'll believe anything. Hi Reg......how so?, i regard you as among the knowlegeable and look forward to your thoughts on the EH that prompts your comment, `tho it does seem like something for nothing, i don`t wish to appear too dumb!!....i`m currently playing with a helical on 40 and am thinking of making a dipole with a matching helical, i can get that in my postage stamp garden......hi So you think the EH is a waste of time then??? ;-) Lee.....G6ZSG... |
#5
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"Lee" wrote Just heard mention of the EH Antenna and that it is rather small but equal radiation to a full size dipole !!!. Sucker! If you believe that then you'll believe anything. Hi Reg......how so?, ============================ Hello Lee, The EH antenna is a hoax perpetrated by somebody who hopes to make money by selling them. His sales description of how the thing works pretends to make use of the mathematical works of James Clerk Maxwell. It may sound good to novices but is just a load of nonsense. Actually, its performance is somewhat worse than other antennas of the same physical size. If it's claims are as marvellous as all that, ask yourself why every amateur doesn't have one, regardless of how big is his backyard. To a smaller extent, the G5RV falls into the same category. You did right to ask your question. ---- Reg. |
#6
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Reg Edwards wrote:
Just heard mention of the EH Antenna and that it is rather small but equal radiation to a full size dipole !!!. Sucker! If you believe that then you'll believe anything. Now, now, Reg. He didn't say equal RF radiation. Heat is also radiation. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#7
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"Reg Edwards" wrote in message ... "Lee" wrote snip Hi Reg......how so?, ============================ Hello Lee, The EH antenna is a hoax perpetrated by somebody who hopes to make money by selling them. His sales description of how the thing works pretends to make use of the mathematical works of James Clerk Maxwell. It may sound good to novices but is just a load of nonsense. Actually, its performance is somewhat worse than other antennas of the same physical size. If it's claims are as marvellous as all that, ask yourself why every amateur doesn't have one, regardless of how big is his backyard. Yes, it did cross my mind but i`ve only just heard of it and as i say, i`m dumb but not too dumb !!! ;-) To a smaller extent, the G5RV falls into the same category. Oh!, i`ve got one of those as a sloper........seems to work somewhat, not brilliant but i can hear stations..... LOL....(wish my garden was bigger :-/). You did right to ask your question. I have an enquiring mind ... ta!. Lee.. |
#8
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"Lee" wrote - i`m currently playing with a helical on 40 and am thinking of making a dipole with a matching helical, i can get that in my postage stamp garden ...... ================================== A back-to-back horizontal helical dipole is a good proposition. Radiating efficiency is what matters with physically small antennas. The radiating pattern is whatever you happen to get. A 1/2-wave helical resonant dipole is considerably more efficient than a 1/4-wave vertical simply because of the absence of ground connection losses. A low dipole does have a small ground loss due to its proximity to ground. Ideally its height should be at least equal to its overall length but half that is a satisfactory compromise. A horizontal helical dipole is the same as a centre-loaded wire with a very long loading coil. It is easier to match to a feedline than a vertical and there is a choice of type of line and line impedance. Either coax or balanced line can be used. Make the loading coil continuous through the antenna centre and enclose the centre with a link coupling to the feedline. The number of turns on the coupling link is dependent on line impedance. The antenna itself is electrically isolated from the line and remains nicely balanced about ground. The greater the diameter of the loading coil former, a rigid plastic pipe, and the thicker the wire, the higher the efficiency. For 100 watts transmitters, close wound turns of thick enamelled wire are usually OK. Resonant frequency is adjusted by pruning the length of the wire or rods which extend beyond the ends of the coil. If essential due to space limitations, the end wires can be allowed to fall down towards the ground but not allowed to swing about in the wind. Short loaded antennas are essentially single frequency, very narrow bandwidth devices. Download program MIDLOAD from website below. It may be of assistance or at least provide you with something to think about. In postage-stamp backyards, size-for-size, Magloops are the most efficient of all very small antennas and can cover several adjacent bands, but are deceptively difficult/easy/expensive to construct depending on your ingenuity. Download program MAGLOOP4. ---- .................................................. .......... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp .................................................. .......... |
#9
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In message , Reg
Edwards writes "Lee" wrote Just heard mention of the EH Antenna and that it is rather small but equal radiation to a full size dipole !!!. Sucker! If you believe that then you'll believe anything. Hi Reg......how so?, ============================ Hello Lee, The EH antenna is a hoax perpetrated by somebody who hopes to make money by selling them. His sales description of how the thing works pretends to make use of the mathematical works of James Clerk Maxwell. It may sound good to novices but is just a load of nonsense. Actually, its performance is somewhat worse than other antennas of the same physical size. If it's claims are as marvellous as all that, ask yourself why every amateur doesn't have one, regardless of how big is his backyard. To a smaller extent, the G5RV falls into the same category. You did right to ask your question. ---- Reg. Didn't Radio 252 (252kHz) near Dublin start out using an E-H antenna? And wasn't there a new high-power SW station in Egypt which was supposed to use one too? I've feeling that with the latter, they pulled it down and used a conventional antenna. Ian. -- |
#10
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"Reg Edwards" wrote in message ... "Lee" wrote - i`m currently playing with a helical on 40 and am thinking of making a dipole with a matching helical, i can get that in my postage stamp garden ...... ================================== A back-to-back horizontal helical dipole is a good proposition. Radiating efficiency is what matters with physically small antennas. The radiating pattern is whatever you happen to get. A 1/2-wave helical resonant dipole is considerably more efficient than a 1/4-wave vertical simply because of the absence of ground connection losses. A low dipole does have a small ground loss due to its proximity to ground. Ideally its height should be at least equal to its overall length but half that is a satisfactory compromise. A horizontal helical dipole is the same as a centre-loaded wire with a very long loading coil. It is easier to match to a feedline than a vertical and there is a choice of type of line and line impedance. Either coax or balanced line can be used. Make the loading coil continuous through the antenna centre and enclose the centre with a link coupling to the feedline. The number of turns on the coupling link is dependent on line impedance. The antenna itself is electrically isolated from the line and remains nicely balanced about ground. The greater the diameter of the loading coil former, a rigid plastic pipe, and the thicker the wire, the higher the efficiency. For 100 watts transmitters, close wound turns of thick enamelled wire are usually OK. Resonant frequency is adjusted by pruning the length of the wire or rods which extend beyond the ends of the coil. If essential due to space limitations, the end wires can be allowed to fall down towards the ground but not allowed to swing about in the wind. Short loaded antennas are essentially single frequency, very narrow bandwidth devices. Download program MIDLOAD from website below. It may be of assistance or at least provide you with something to think about. In postage-stamp backyards, size-for-size, Magloops are the most efficient of all very small antennas and can cover several adjacent bands, but are deceptively difficult/easy/expensive to construct depending on your ingenuity. Download program MAGLOOP4. Yes had a look at that one, gave me a few ideas as i like constructional projects.....You`ve given me a lot to think about Reg, it`s either a helical dipole or a magloop ..... there is a helical 40mtr beam in the ARRL handbook i`ve been looking at too.... Thanks . Lee. |
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