This thread has really given me things to try when earth tilt/absence of white rain is back in our favour. Great group of folks on this forum btw.
The many contributions to this thread have given me the confidence to try end feds (for the first time) on my up coming trip to HI9 land. I'm packing a few end fed lengths for whatever the trees on the resort will support. I'll start with Wayne's 25ft radiator and 25 ft wire on the ground suggestion first. Again this untried for me. Before getting my kx3 I used an FT817 and the ATAS25. Worked fine when 20 to 10m openings were easier to come by a few years ago. Now my thoughts are about the reactions I'll get throwing something at a tree or two on the resort near the beach. I've managed to strip my CrankIR down to 12lbs so I'm taking it anyway only because I've used it/know it. The goal is to no longer feel the need to cram it into charter flight size and weight constraints and keep it for car trips instead. I'm guessing throwing a half full water bottle will suffice. Corrections invited. Now my thoughts are about permanent end fed resonant wires (vs dipoles) for the home shack. I currently have a home brew 80/40 centre fed dipole tied from the house to a tree in the woods. If that were instead an end fed resonant wire fed by a 9:1 at house end things could get much simpler (and less saggy) coax wise. Now comes the fantasy thinking... What about making it an end fed multi band by either putting traps in the 80m end fed or better still adding on a couple of fan EFHW wires for 40 and 20? Anyone tried this? How would the efficiencies compare to their centre fed trap or fan dipole counterparts respectively? Then there is that 160m antenna I'm think about putting up this summer... Brian ve3bwp Date: Fri, 10 Feb 2017 12:05:56 -0600 From: K9MA <k...@sdellington.us> To: elecraft@mailman.qth.net Subject: Re: [Elecraft] EFHW Message-ID: <bf058500-e443-0a91-c789-06f1abd23...@sdellington.us> Content-Type: text/plain; charset=windows-1252; format=flowed Here's the old trade-off between radiating efficiency and ease of matching for an end fed wire. The EFHW is more efficient, because little power goes into the ground system, but its high impedance is harder to match. A wire of a different length may be easier to match, but more power goes into the ground system, where it doesn't radiate much. Both will work but, I believe, on average the EFHW will be a bit better. Is it worth the trouble? Who knows? Antenna discussions have long had a tendency to focus on SWR. Low SWR does not necessarily mean an antenna is effective. There's an old saying, "The SWR of a dummy load is 1:1." 73, Scott K9MA On 2/10/2017 09:56, Don Wilhelm wrote: > Brian, > > If your end fed antenna is actually a halfwave (which is what EFHW > means), the answer is no. > > The solution for portable work is to use a length that is not a > halfwave - 58 feet is known to work well for 40 thru 10 meters when > used with a 13 foot counterpoise. Double the lengths if you want 80 > meters. > > With that antenna and counterpoise length, dispense with the balun for > portable operations, and use a BNC to Binding post adapter instead (no > coax). > > If you need to use a short length of coax, you can put the balun at > the end of the coax, and you can try both the 1:1 and 4:1 positions to > see which provides the better match. > > 73, > Don W3FPR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
