EFHW is a great antenna. It works but only if tuned correctly. Bad news is it would be difficult to do the tune job for any ATU, even the Elecraft, due to the very high impedance ( up to the 5kohms). Please read everybody the aticles by the EFHW guru here : http://www.aa5tb.com/efha_wrk.html. STeve explains very clearly the whole theory behind the EFHW, the length of "counterpoise" etc.
I have built and used many of the EFHW antennas in different configurations , including usage of the loading coils in the multiband operations in order to make the wire shorter on the low bands. The tuner is the simplicity in itself if used on qrp levels. For the higher power levels the coil/capacitor choice must be high ( very high!) RF voltage- proof. Surely , the tuner , as good as Electaft makes, and the random lenght NON resonant wire is the excellent solution for the portable work but then you need a kind of ground whatever you can get at hand. Have tried it for many years with the Elecraft T-1 tuner with great success working 5 W from the hotels accross Europe tuning anything I could- window frames, rain water pipes, random pieces of wire, :)... 73 de Linas LY2H, ex ON4BHP On 2017 vas. 14, an at 20:20 Gil G. via Elecraft <elecraft@mailman.qth.net> wrote: > > I will second Guy here. > The best antenna I have ever used is the vertical EFHW. I never used a > counterpoise wire, never felt that tingling in your fingers you might feel > with a random wire and a metal key. > I have used 100mW to 500mW regularly with end feds with great results, > single hop up to 1300 miles, 5K miles on 1W. > I say that having built all kinds of antennas and used them in all sorts > of configurations, random wires, with and without counterpoises, slopers, > inverted Vs, dipole, Windom, magnetic loops, quad, short whips, yagi, and > except for the beams nothing beats the EFHW! > A horizontal dipole might perform as well but they are rarely high enough > to perform as well, except of course for NVIS on the lower bands, and then, > a horizontal EFHW will work as well. > The only antenna that came close in performance was a large magnetic loop. > Whatever the theory says, I am talking about real in-the-field performance > where nothing comes close. > Gil > AK4YH & F4WBY > -- > Sent from Mail.Ru app for Android Tuesday, 14 February 2017, 05:48PM > +01:00 from Guy Olinger K2AV k2av....@gmail.com : > > >In spite of ON4UN's 4.3, I stand by my prior statements concerning the > >excellence of end-fed half wave antennas (EFHW), and their non-existent > >requirements for vast counterpoise. In that specific regard, ON4UN is > >unfortunately off the mark. More on that below. > > > >Those of you using the becoming popular (?) EFHW portable antennas with > >your excellent Elecraft portable rigs, you do NOT need to worry about > >putting down a dense 0.35 wavelength radial field for them to work very > >nicely. > > > >I've had 50 plus years experience with 80m EFHW antennas, particularly the > >EFHW inverted L or EFHWL. I, and all those I have helped install one to > >improve their signal, have had very successful experience with EFHW aerial > >wires. It's long-term lack of general popularity among hams has always > been > >curious to me. I personally attribute that to the lack of a robust > >commercial **remote** tuner **made for the purpose** to go at the base. An > >off-the-shelf version has always been needed to serve hams who for > whatever > >reason are unable or disinclined to construct these devices for > themselves. > > > >None of this 50+ years of excellent EFHW experience included a 0.35 > >wavelength radial field. They all included very minimalist counterpoise, > >including maybe one hand's worth fed against a ground rod. I remember one > >just outside a window and within a few feet of the property line. I never > >recommended a ground rod, but I must admit that those worked tremendously > >better than what they were previously using. And it was their house, not > >mine. Who knows what kind of blowback they were getting about antennas. > >Back then radio could put lines through TV signals and create next door > >enemies. > > > >I will further add that an 80 meter end-fed halfwave L, and against very > >minimalist ground or counterpoise, is arguably the **best** single wire > >80/75m antenna for **both** DX and local contacts, and as such a real > >winner for small lot situations. Especially for those small lotters where > a > >hundred foot radius for Mr. Devoldere's 0.35 wavelength dense 80m radial > >field runs into the street and through three or four adjacent houses :>) > > > >At my place that would be through my house, across my driveway, through > >neighbor Tim's deer fence, across his driveway and into his wife's flower > >garden, and toward the back into dense woods where radials are problematic > >elevated or buried. > > > >According to Mr Devoldere, that shouldn't work. > > > >OK. Then do this: > > > >http://3830scores.com/editionscores.php?arg=RNfmy1zEgqmmL > > > >On the "Sort by" line set "show" to USA and click on "go" > > > >Do a CTRL-F on K2AV. That will be 256 Q's, 18 zones and 80 countries in a > >distracted, very part-time single band effort. Not bragging (I hate > >bragging along with most everyone else), but if minimal counterpoise is no > >good for voltage-fed antennas, then explain that score by a distracted > >decent but otherwise hardly-a-genius operator. > > > >The antenna was an 80EFHWL over a 160m FCP flipped to 80m (explained > >elsewhere). That's essentially an elevated pair of 0.125 wavelength wave > >radials, +/- 33 feet. Not on the same planet as a dense 0.35 radial field. > >So then how does one reconcile the ON4UN ain't gonna work text with most > of > >a single weekend 80m DXCC in a frequently interrupted part-time effort? > > > >This 80EFHWL was 80m dual-use-ing my 160 inverted L over an FCP, with no > >loading coils or additional radiating wires. We have proven this technique > >at two other stations with excellent results. More on that, later, > >elsewhere. > > > >Back in the day I had an 80EFHWL with two 15 foot buried bare wires > running > >away from a basement window as a counterpoise. On 80 meters and living in > >New York state, taking message traffic on the Eastern Area Net, I was one > >of the handful of stations able to consistently check directly into the > >Pacific Area Net and forward that traffic directly to Pacific coast > >stations when the normal off-net relay failed to show up earlier on 40 or > >20 meters. And that was when 4 811A's running the then 1 kW **input** > legal > >limit could only put about 700 watts on the antenna. > > > >I do have ON4UN's book, and have always and still do hold him in high > >regard. But he, like some number of others, have been led astray by > Brown's > >curious assertion about halfwaves. That's the Brown from Brown, Lewis, and > >Epstein of the famous 1937 RCA study on towers and radials. > > > >That ground current format is not duplicated in a NEC4 model of a base-fed > >halfwave vertical. Brown's assertions in this regard have pretty well been > >discarded as a model for ground current. Instead what you see in NEC4 has > >largely been adopted. In deference to Mr. Brown, many of us (including me) > >still harbor an unsatisfied curiosity as to what/where those measurements > >and assertions really came from, given our very high regard for the rest > of > >his work. > > > >A potential clue is that modeling a vertical halfwave **grounded** at the > >base, and **fed up at the center**, DOES show the increasing current and > >fields peaking out at the extremes of the radial field. Could it be that > >Mr. Brown was referring to that, and somewhere in the time since, the > >specification of grounded at the base got lost, thus leading to our > >persisting urban myth? Alas, Mr. Brown has long since gone to the great > >Radio Engineer's convention in the sky, and we probably will never know. > > > >We must also remember that Mr. Brown was developing his theses for > >**commercial** low band broadcasting, which is primarily, overwhelmingly, > >interested in **ground wave**. That is where advertising-targeted > customers > >for local businesses lived in an era decades before the internet, Amazon, > >and real customers of a "local" business were scattered all over the > globe. > > > >On the other hand, almost entirely, hams are interested in sky wave, and > >consider lower angle sky wave for DX and NVIS sky wave for "close in" > >coverage, not ground wave. > > > >The point of these gargantuan BC band halfwave and fullwave antennas has > >always been to squeeze out the last little drop of intensity AT THE > GROUND, > >to extend the range AT THE GROUND, to solidly cement the circle where for > >advertising the station could verifiably claim solid signal strength to > >daytime AT THE GROUND listeners. And, particularly, do that while > >minimizing their 24/7 power bill. > > > >A commercial BC station must hit a SPECIFIED signal strength (neither > >higher nor lower) at various points at the ground. Getting that intensity > >by improving the tower, rather than increasing the 24/7 power bill, is a > >recurring cost reason for all the worry about ground wave. > >Radial/counterpoise efficiency at ground relates to recurring expense. A > >tower is a one-time capital expense. Long term cost/benefit analysis. > > > >We have got to get over our bad habit of extrapolating every little nit of > >the BC band paradigm into ham radio without adjustment for the large pile > >of differences between their goals and needs and ours. > > > >73, and do enjoy your EFHW's with your neat bitty Elecraft boxes. It's > >about time. > > > >Guy K2AV > >______________________________________________________________ > >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 gil...@yahoo.com > ______________________________________________________________ > 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 irmalina...@gmail.com > ______________________________________________________________ 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
