Many thanks for all of the help with my problems with reception at the lower
120MHz
freq range.
Following Fred's instructions I build the optimum antenna from 6 mm dia.copper
wire ( quarter of an inchish for the old Imperial types). It worked perfectly
with low - zero reflection across the useful range of frequencies, and a high
forward performance throughout. This was with the perfect shape.
Regrettably to fit it into the rear of my Europa I had to bend the shape into
something
which was far from perfect. This had a seriously adverse effect on the
performance. When this was coupled with the proximity of two human shaped bags
of liquid, and a variety of hardware essential to the workings of my aircraft,
it made the 'Fillinger Special' an impractical alternative to the fin mounted
di-pole.
All of this effort had involved me in two days of work, but I had learned a lot.
Going back to the Di-pole. I tested it through the range of frequencies. Much to
my surprise I found the reflection to be fairly low in the lower frequency range
( 120- 128 MHz ). It rose to it's worst values above 130 MHz. I have never
had reception problems in that range. Curiouser and curiouser!
Now listen to this Bob H! Finally I strapped my Europa on, and took it out for
some practical radio testing. Bob has told me that he cannot receive Conningsby
(120.8), Humberside (119.125) without dumping the squelch, so I went to try
them. I was particularly interested in the Conningsby frequency (120.8) because
this is the very range thatI have had problems with. Blow me if they did not
both come in fives from twenty miles.
I also tied Bob's other bogey frequency, Wickenby's (hand held) 122.45. They
read
me five, and I read them four.
A last thought. Is it possible that whilst breaking and remaking my connectors
for the tests I had done somthing good? Maybe I should go back to my original
thesis that the French in Lille don't like talking to Derbyshire people ( or
Yorkshire
people Roger Mills).
I think I have had it for now. I'll shuffle off back to the funny farm and rest.
My Woodcomp prop is working well now.
Regards to all.
Bryan
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