So what we are saying here is that all the local and DX QSOs we make from a picnic bench with an end fed or random wire thrown up in a tree and a short or no counterpoise doesn't really happen or, at best, is a fluke. The end fed is only 10% efficient (did I get that right) and most of our QRP signals are going to heat worms. Pretty hopeless situation I guess. I might have to just stick with the local repeater and Google Hangouts for communications.
Or, for those of you that are thinking the situation isn't so hopeless, grab your portable antenna, head out to the campsite, throw your wire up in the tree and I'll catch you on the air. Let's warm up the worms. 73, Kev On Sat, Feb 11, 2017 at 11:54 PM, Ron D'Eau Claire <r...@cobi.biz> wrote: > Ha, ha!!! Well put Wes! > > Some mountain portables erect low "horizontal" antennas on the side of a > steep mountain. The result is a very low angle of radiation because, even > though the main lobe is "straight up" from the mountainside from the > antenna, the slope puts that lobe at a fairly low angle relative to the > earth. > > 73, Ron AC7AC > > -----Original Message----- > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Wes > Stewart > Sent: Saturday, February 11, 2017 8:02 PM > Cc: elecraft@mailman.qth.net > Subject: Re: [Elecraft] EFHW > > It is with some reluctance that I smack this whole EFHW tarbaby, but here > goes. > Comments in no particular order: > > 1) A resonant antenna (even one that is self-resonant), e.g. one with a > non-reactive feedpoint, isn't necessarily "efficient." A > quarter-wavelength monopole over lossy earth leaps to mind. > > 2) A non-resonant antenna isn't necessarily inefficient. The ever > popular G5RV isn't resonant on the band of interest (20M) but when fed > appropriately, was as efficient as a resonant dipole. > > 3) Consider a BC band 1/2 wavelength vertical antenna. Does the station > designer say, "Well, this EFHW doesn't really doesn't need much of a > counterpoise, so I'll just throw a 100' long wire on the ground and call it > good enough?" No, he install 120 radials that are even longer than the > ones he would use under a 1/4 wavelength monopole. Devoldere in "Low-Band > DXing, Chapter 9, Section 4.3 says: "Here comes another surprise. A > terrible misconception about voltage-fed verticals is that they do not > require either a good ground or an extensive radial system.'" Later in the > same section he says, "Therefore it is even more important to have a good > radial system with a voltage-fed antenna such as the voltage-fed T or a λ/2 > vertical. These verticals require longer radials to do their job > efficiently compared to current-fed verticals." > > 3) When you backpacking mountain goats say, "Hey my wire isn't a > vertical, it's mostly horizontal", I say, if your radio is sitting on a > boulder or the ground, it's a vertical and your wire-on-the-ground > counterpoise proves it. > > Wes N7WS > > > > On 2/11/2017 2:33 PM, Ron D'Eau Claire wrote: > > All efficient antenna systems are "resonant" (jX=0) but the shorthand > > often used is "resonant" to mean "self resonant". That is true of any > > 1/4 wavelength long radiator (again our common shorthand is usually > > "1/4 wave > > wire") or any multiple thereof worked against ground. It is also true > > of any half wave length radiator or any multiple thereof. (Note that > > these are electrical lengths, taking into account any surroundings > > including the radiator itself.) > > > > While self-resonant antennas do not present a reactive load to the > > source of RF power, the value of R, the resistance, may vary widely. > > There is nothing magic about the 50 ohm load most of our transmitters > are designed for. > > > > However, a half wave radiator fed at the center presents a resistive > > value near 50 ohms when fed at typical heights above ground (in free > > space it is > > 75 ohms). Half wave antennas became very popular after WWII because > > 50-ohm coaxial feed line became abundant and cheap on the "surplus" > > market and Hams were taking steps to deal with needing to avoid > > interfering with the rapidly growing number of TV sets in nearby > > homes, including the Ham's own living room. > > > > In the following decades, greater and greater demands on harmonic > > suppression have led to Ham transmitters with output filters > > specifically designed for a 50 ohm load instead of being able to match > > a wide range of load impedances. > > > > So we have now moved the wide-range output network that was in > > Grandpa's Ham transmitter out of the transmitter and into what we call > an "Antenna Tuner". > > But, of course it does not "tune" an antenna at all. It's just a > > matching network to be sure the transmitter is delivering power to a > > load close to 50 ohms and non-reactive. > > > > 73, Ron AC7AC > > > > -----Original Message----- > > From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of > > Wes N7WS > > Sent: Saturday, February 11, 2017 12:44 PM > > To: Charlie T, K3ICH > > Cc:elecraft@mailman.qth.net > > Subject: Re: [Elecraft] EFHW > > > > jX = 0 > > > > Sent from my iPhone > > > >> On Feb 11, 2017, at 1:29 PM, Charlie T, K3ICH<pin...@erols.com> wrote: > >> > >> Define "resonance". > >> > >> Chas > >> > >> -----Original Message----- > >> From: Elecraft [mailto:-boun...@mailman.qth.net] On Behalf Of Fred > >> Jensen > >> Sent: Saturday, February 11, 2017 2:40 PM To:elecraft@mailman.qth.net > >> Subject: Re: [Elecraft] EFHW > >> > >> Ummm ... A full-wavelength wire is not resonant? > >> > >> 73, > >> > >> Fred ["Skip"] K6DGW > >> Sparks NV DM09dn > >> Washoe County > >>> -----Original Message----- > >>> From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf > >>> Of Lynn W. Taylor, WB6UUT > >>> Sent: Friday, February 10, 2017 12:13 PM To:elecraft@mailman.qth.net > >>> Subject: Re: [Elecraft] EFHW > >>> > >>> Just a reminder, folks. > >>> > >>> If it's not a half-wave, then it's a non-resonant wire. > >>> > >>> > > ______________________________________________________________ > 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 r...@cobi.biz > > ______________________________________________________________ > 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 ke...@k4vd.net > ______________________________________________________________ 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
