Very interesting question Dave...I was just wondering why I never saw any
comments on this "new" receiving antenna design.
It has been published by KB7GF on QST Oct.2012 and on QEX Sept/Oct. 2012.
It's quite different from the usual small loop types, flags,pennants, K9AY,
etc...
But contrary to these resistor loaded loops, which always want to work, this
Shared Apex Loop looks like critical and not so easy to build!
Anyway before going deeply and trying it, I was waiting for the opinion and
comments of the most authoritative contributors to this reflector, first of
all Tom, W8JI, to whom we must be always grateful, but also N4IS, NX4D and
many ithers.
73
Luis IV3PRK
----- Original Message -----
From: "David Cole" <g3rcq@yahoo.co.uk>
To: <topband@contesting.com>
Sent: Friday, January 25, 2013 10:27 PM
Subject: Topband: RDF
How do I calculate RDF – I am currently modelling the Shared Apex Loop
antenna recently described in QEX and QST , Not to be confused with the
following months article on phased K9AY’s - I have an 8 direction antenna
up and running and now wish to add 8 more elements to the array. I will
then have three shared apex loops in anyone of 8 directions. I have using
Eznec modelled the array and the optimum spacing is around 50 feet and the
phase delays 0 100 200 appear to give good F/B and F to side – this leaves
me to the original RDF question – in Eznec the Average Gain is
calculated – now is the same average gain that the RDF formula needs? It
does appear to coincide with figures quoted in the original article for a
single array rising to 12.1 db for the three in line array. However if I
use the same method and model my 8 Element full size 80m array then the
results are not as expected when I try and calculate RDF.
Dave
g3rcq
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