[Elecraft] [AX1] Who has the AX1 antenna DX record?

[David Gilbert]

It's not the takeoff angle that makes the difference here.  The takeoff 
angle of a half wave vertical dipole over real ground is not much 
different than the takeoff angle of a quarter wave (or shorter) vertical 
fed against a ground plane or counterpoise.

I'm pretty sure that what's really going on here is that as you make the 
counterpoise wire more vertical the counterpoise is becoming the primary 
radiating element  The AX1 essentially becomes a loaded "counterpoise" 
for the vertical trailing wire.  I wouldn't be surprised if the 
counterpoise wire does most of the radiating even if trailed across the 
ground, although much of it would be lost to the lossy earth and the 
rest pointed upward.  If we were able to model the AX1 with the 
counterpoise we'd most likely see that the integral of current as a 
function of length for the counterpoise wire exceeds that of the AX1, 
and if the AX1 was vertical and the counterpoise horizontal most of the 
radiated energy would be horizontally polarized.  Somebody could easily 
prove (or disprove) this with a short sense antenna and a field strength 
meter.

I suspect lots of people won't like this perspective, but there it is.

73,
Dave   AB7E




On 5/29/2019 1:52 PM, Adam Goler wrote:
> I also anecdotally observed greater propagation with the counterpoise wire
> hanging vertically this past weekend.
>
> Intuitively, using a vertical counterpoise, as the "feedpoint" increases in
> height away from the ground plane of the Earth, the takeoff angle should
> decrease as the radiation pattern more and more resembles a free-space
> vertically oriented dipole field (picture a field shaped like a donut).
>
>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Tue, 28 May 2019 13:24:03 -0400
>> From: Hank <hbjr at optilink.us>
>> To: VE2PID <ve2pid at videotron.ca>,       elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] [AX1] Who has the AX1 antenna DX record?
>> Message-ID: <5bd0e4be75154c7f58e74eb7ee1b7108 at optilink.us>
>> Content-Type: text/plain; charset=UTF-8
>>
>>
>> Good info!
>>
>> I have noticed from operating in the field that I make more contacts if I
>> lay the counterpoise along the ground. ?I get better signal reports from
>> stations in the direction of the counterpoise.
>>
>> I noticed from operating this weekend at an overlook that with the
>> counterpoise over the side of the overlook going down hill at roughly 30
>> degrees, my contacts were clustered farther away - again in the direction
>> of the counterpoise.
>>
>> I was operating on 20 and 17 with the AX1, KX3, SSB at 15 watts.
>>
>> Hank
>> K4HYJ
>> ?
>> ----- Original Message -----
>> From: VE2PID (ve2pid at videotron.ca)
>> Date: 05/28/19 11:30
>> To: elecraft at mailman.qth.net
>> Subject: Re: [Elecraft] [AX1] Who has the AX1 antenna DX record?
>>
>> ... I used the AX1 as a test in WPX CW last weekend for only an hour on
>> a picnic table. No problem ...in that time I got 13 QSOs from FN45
>> including FL. (10 Watts KX2, 13' counterpoise).
>> --
>> After NEC simulations (0.005, 13 average ground) , we find how the gain
>> is maximized in the direction of the counterpoise. On 20 meters, if the
>> wire is horizontal at 4 feet height, the take-off angle is about 56
>> degrees. But if the wire goes down from 4 feet to the ground (15 degrees
>> slope), the F/B is less but the take off angle is lower at 35 degrees
>>
>> (Image at https://i.imgur.com/XKPjM8T.jpg )
>>
>> 73, Pierre VE2PID
>>
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>
>