Warren
Things have gone downhill since the introduction of Ferrite Stick antennas,
uProbe antennas etc the K9AY antenna is a good sized loop antenna and does
well. I use a 40 metre quad loop for general RX reception and resonate it on
the band of interest and it works well but not as good as a full size
antenna for MF/LF. If space is available a full size antenna for the band of
interest is preferable and if not then the inv L  and loop antennas as large
as possible are the next best choice, after that pocket size antennas work
after a fashion but do not expect miracles.
The pocket sized antennas are ok for High power Broadcast reception but poor
for weak radio amateur signals.
73 de mal/g3kev

----- Original Message -----
From: "Warren Ziegler" <[email protected]>
To: <[email protected]>
Sent: Sunday, May 13, 2012 6:34 PM
Subject: Re: LF: Cardioid RX antenna for LF...


Stefan,

   See Dallas Lankford's site:
http://groups.yahoo.com/group/thedallasfiles/

Yes F1AFJ used a K9AY with excellent results (until a local source of
QRM appeared) Jean-Pierre even copied some T/A signals into daylight!
Also Jay  W1VD and Hartmut Wolff used similar antennas, see:
http://w1vd.com/k9ay11.pdf
http://jpmere.online.fr/L_F/Les%20LF.htm  (scroll to bottom)

73 K2ORS


On Sun, May 13, 2012 at 1:41 PM, manginbenoit.pro
<[email protected]> wrote:
> GE Stefan and all,
>
> Try and see Jean-Pierre / F1AFJ 's page, he built and modeled a 2-turn
K9AY,
> the one he uses for his grabber.
>
> Nothing to say about performance, it seems. Judge it by the summer T/A
> captures... Plus, (I did not test it) his QSD RX es MMIC preamp seems to
> work VY FB.
>
> I tried a 2-turn K9AY for 160, but it is definetely too long, there is too
> much wire. 0,2 lambdas seems to be a maximum. Voltage levels are correct
but
> directionnal properties degrade seriously.
>
> Nevermind on 137, we will never reach a quarter-wave long RX antenna !!!
>
> Maybe a 2-turn Flag should be tested ? Does anybody use MMANA ? I can try
> and model one using this software.
>
> I don't use EZNEC at all.
>
> de F8GRY/Ben
>
>
>
>
>> Message du 13/05/12 19:12
>> De : "Stefan Schäfer"
>> A : [email protected]
>> Copie à :
>> Objet : LF: Cardioid RX antenna for LF...
>
>>
>> Hello Group,
>>
>> I've just started to play a bit in EZNEC, trying to simulate a receive
>> loop antenna for the new YV7MAE grabber.
>> http://dl.dropbox.com/u/74746618/LF/YV7MAE_LF_Grabber.html ... still
>> using a wire receive antenna with excellent results but now a
>> directional antenna is needed.
>>
>> So i modelled a loop with a possible shape and a ground connection. Then
>> i added a R on the far end of the source. The results of the elevation
>> and 3D plot are surprising good. Maybe i have done a mistake in
>> modelling? Optimal performance was obtained at R = 8 kOhm. This resulted
>> in the best F/B and beamwidth... Results of ZENEC are here:
>> http://dl.dropbox.com/u/19882028/LF/Cardioid%20for%20LF.png
>>
>> Any ideas, experiance or advice?
>>
>> I guess a preamp is needed when such a antenna is used. The typical 1:9
>> un-un does not look useful for me...
>>
>> 73, Stefan/DK7FC
>>
>>



--
73 Warren K2ORS
WD2XGJ
WD2XSH/23
WE2XEB/2
WE2XGR/1