> OK - based on the responses I have, the K9AY seems to be a good way to go
for very limited space, with the following provisos: ....
> KB0HFP
--------------->
> TWO more :
>
> Vactrol (that is analog optical isolator) or any other means of
> distant adjastment of loading resistor is a MUST!
>
> Simple rewiring converts classic 2 loop K9AY into 8 directional array
> with a narower front lobe in a 4 "new" directions
>
> RA6LBS
------------------
I have recently confirmed that the use of a Vactrol is highly overrated. An
examination of Vactrol data shows poor temperature stability as well as
resistance drift over time. I believe that much of the "tuning" observed by
Vactrol users is simply re-adjusting the voltage to correct for the drift.
I have just begun manufacturing the AYL-4 K9AY loop system with 8 selectable
termination values (incremental values, not continuously variable). I
performed extensive tests on the new system and found that my own loop only
needs two settings, one for 80M and the next lowest resistance for all lower
frequencies.
Remember, the termination resistance does not "tune" the antenna or change
the location of the nulls. The termination only optimizes the depth of the
null, which may require slightly different values at different frequencies.
The optimum termination may change seasonally with varying ground
conditions. Adjustable termination is also handy if you build a K9AY loop
with a different size or shape than the published design (such as the extra
directions in the 8-way system).
BTW, the 8-direction system does not have a narrower front lobe, but it does
allow a null every 45 degrees, which can be useful.
73, Gary
K9AY
PS -- Array Solutions will have the new AYL-4 version about Jan. 10.
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