Dave, I've done many variations on whip antenna tests.
A resonant 4' whip with or without a counterpoise is on a different planet from a resistor. If an AX1 were listening in on this conversation, it would challenge you to a duel, with live ammo :) In fact the counterpoise is absolutely required for transmit, but you can get away without it on receive, where body capacitance to ground alone will suffice, even on the HF bands. Try this test: Go outdoors and connect an AX1 (or equivalent) to the antenna jack of any 20 meter receiver. With r without the counterpoise You'll get of noise, lots of signals. Now replace the wire with a resistor. Nothing. QED.... Wayne N6KR > On Sep 21, 2022, at 7:29 PM, David Gilbert <ab7e...@gmail.com> wrote: > > > > Well, the reason I mentioned the 50 ohm resistor is that a year or so ago > somebody on this reflector mentioned that he did a direct comparison between > an AX1 with the recommended 13 foot wire counterpoise and with no > counterpoise at all. I don't remember for certain but I think he said he > used the RBN. I do remember that he said the difference in signal strength > was about 30 db. For grins I used EZNEC to model a single 50 hm resistor 15 > feet off the ground with and without a 13 foot wire hanging from one end of > it. I got 30 db difference in calculated signal strength. > > I am by no means claiming that is a definitive or even relevant test ... I > just think it would be interesting to actually do an empirical comparison. > > It is my opinion, however, that most of the radiating on an AX1 (or any other > short loaded whip) is being done by the counterpoise wire and/or the shield > of the coax. The coil and whip are matching aids. If so, it's possible that > a resistor would accomplish the same thing. ;) > > As I said, I'd be willing to do the comparison if anyone is willing to lend > me an AX1. I'd be happy to be proven wrong. > > 73, > Dave AB7E > > > > On 9/21/2022 6:46 PM, j...@kk9a.com wrote: >> Thomas Schiller, N6BT once wrote an article titled "Everything Works". In >> the article he discussed how he worked all continents on CW (a mode that you >> can actually hear) using a light bulb antenna during the ARRL DX contest. >> >> The AX1 appears to be a 45" whip with a base inductor made of 20AWG wire. I >> am not sure what is inside the base, if anything, to bring the impedance up >> to 50 ohms. With some sunspots, I am sure that it is fun for pedestrian >> mobile use which is what it's designed for. A 1/2wl dipole or 1/4wl vertical >> will be a much better radiator. >> >> John KK9A >> >> >> >> >> David Gilbert ab7e wrote: >> >> A comparison to any other antenna would be useful. A comparison to a 50 >> ohm resistor with a similar counterpoise wire would be even more useful >> as a baseline measurement. If anyone wants to lend me their AX1 I will >> do that. >> >> 73, >> Dave AB7E >> >> >> On 9/19/2022 10:33 AM, Ron Gruner wrote: >>> I've been impressed by how well my little AX-1 whip antenna performs on 20 >>> meters. Here's a photo of the rig: https://gruner.com/k4rhg/andover_ma.png >>> and the propagation map: >> https://gruner.com/k4rhg/wspr_2watts_sep16_2022.png >>> A friend, Derek Rowell (AK1WI), gave me a two-watt WSPR kit he had >> designed >>> -- easy and fun to build. I connected the unit to the AX-1 sitting in a >>> window sill facing west and strung the out-of-the-box counterpoise over a >>> lamp shade and bed headboard. No idea what the SWR is, but it must be >>> pretty good. >>> >>> I immediately began receiving propagation reports and within 24 hours had >>> reports from 240 unique stations. The farthest was VK5ARG (17,276 km) with >>> a SNR of -21. Even though the window faced the west, propagation into >>> Europe was strong with SV9KI (7,800 km) reporting -26 SNR. The >>> propagation report is from http://wspr.rocks/ <http://wspr.rocks/> >>> >>> I've found that WSPR is a great way to evaluate antennas. The AX-1 seems >>> to be performing very well. >>> >>> 73, >>> Ron Gruner >>> K4RHG >> ______________________________________________________________ >> 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 ab7e...@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 n...@elecraft.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
