Many thanks to everyone who helped in my efforts to get my Waller Loop working
correctly. Carlos very kindly sent me an email showing me the effect his tower
has on altering the polar plot, his recommendation was detune the tower - this
cured his problem - there is a free Polar plotting program available on the
net - to answer other questions the transformers were made using the binocular
cores as recommended in ON4UN's book, the 9:1 I used 4 and 12 turns, resistors
are 560 and 580 ohms and the 1:1 was 4 turns primary and secondary again using
a binocular core.Moving onto Eznec - this is very strange as I found a
different outcome to my model - I started by downloading the file from Lee's
comparison table, this did not have a boom, I added my 26 ft boom and the
result was a change for the better in front to back! - I then added my tower
into the model and the whole polar diagram fell apart this is different to what
Jim found in his Eznec model - so I am not sure, however the final proof to my
problem was in my last test. The antenna was mounted above my tower using a
fiber glass scaffold pole, I took the complete antenna off the tower and placed
it 20 feet up at ground level in one corner of my field - I took no common mode
protection because I buried the feed cable 150 feet in to my shack. PERFECT -
the antenna worked as it should, good F/B - on 40m beaming into Germany the
stations when compared to my 2 phased 4 squares I was seeing I reckon around
20 ish dbs F/B. Its early days and I need to wait for the DX season to start so
that I can compare with my beverages, however my immediate feeling is that the
loops need to be bigger as there is not enough pick up - I have the low noise
pre-amp which helps but at the moment the beverages appear slightly
better.Thanks again to everyone who replied. Regards Dave g3rcq
_________________
Topband Reflector Archives - http://www.contesting.com/_topband
|