radio / vario interference - HELP!

On Sat, 25 Oct 2003 18:15:54 +0000, Chris Davison wrote:

A problem with interference, all advice welcome.

.radio by itself works fine...but when I turn the vario on I get huge
amounts of noise (even some with Squelch ON). Radio is a Dittel FSG50,
vario is Cambridge 302/303.

Where do I start looking?

Chris

I had a similar, but much worse problem, with an early 2 channel Magellan
GPS about 10 years ago. The GPS was mounted in a bracket on the panel of
my Nimbus II. The antenna was remote mounted on top of the instrument
panel with a foot long extension cable. There was a power cable with an
integral DC regulator which plugged into a 12V power socket that I fitted
behind the panel.

The interference was so bad that it would break through the squelch on the
radio of the glider lined up behind me on the start grid!

I eventually fixed it by wrapping both the antenna cable and the power
cable with steel wool (the stuff Grandma used for cleaning pots in the
kitchen). I pulled a large size shrink wrap over the wool and shrunk it in
place. The result was two rather ugly cables of nearly 1 inch diameter -
but no interference!

The 2 channel GPS had a habit of loosing the satellites in a thermal but
on the glides it would lock in and give a readout within a minute or so.
It cost me a small fortune at the time but was much less than price of a
more sophisticated unit. Compared to map reading it was great! I flew many
thousands of km with that setup.

Ian