[Elecraft] Elecraft AX-1 Whip Antenna

Thu Sep 22 01:12:28 EDT 2022

I believe what Wayne meant to say was’now replace the AX1 with a resistor’ not a wire. Nonetheless the AX1 and 2 still serve a definite purpose in portable operating that a resistor or light bulb won’t 🤪. And I fail to see what the problem is with using a counterpoise,even if it’s doing some of the radiating. Most antenna systems that are unbalanced (verticals,end feds,etc) require a counterpoise. Are you claiming that a resistor with a counterpoise is as effective as shortened vertical?? I believe Rudy Severn’s work has already demonstrated the effectiveness of short verticals with various counterpoises. 
Yesterday I did a SOTA activation where I worked Japan,France and Spain with 5W and the AX1. Obviously the altitude advantage is great and I used 3 13’ radials. I also try to position myself near a sloping edge to maximize my radiation effectiveness (as Tom Schiller N6BT advocates). I doubt a 50 ohm resistor would achieve this… and just in case someone says ‘it’s only because the other stations have big antennas etc ‘ some of the contacts were what we call ‘S2S’ or summit to summit with other activators using similar equipment and power. Perhaps hiking to a bare summit and figuring out what gear you’d haul on your back will give you a certain perspective and appreciation. 

Dan Presley 503-701-3871
danpresley at me. com 
N7CQR at arrl.net

> On Sep 21, 2022, at 20:32, David Gilbert <ab7echo at gmail.com> wrote:
> 
> Why would I replace the wire with a resistor?  I was talking about replacing the AX1 with a resistor and keeping the wire.
> 
> I have no doubt that an AX1 without a wire hears better than a resistor without a wire, but that's mostly because the resistor provides a better match and can't rely on body capacitance or the coax shield.
> 
> If the AX1 was less expensive I'd buy one and do the tests.  I may be totally wrong, but I still say that ANY tuned short whip with a counterpoise is doing most of the radiating from the counterpoise.
> 
> 73,
> Dave   AB7E
> 
> 
> 
> On 9/21/2022 7:59 PM, Wayne Burdick wrote:
>> 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 <ab7echo at 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, john at 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
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