RadioBanter - View Single Post - Transformer for longwire antennas to reduce noise problem?

September 26th 04, 11:18 PM

In article ,
(TheGnome) wrote:

Hey -

I posted in here recently about active shortwave antennas - well, I
managed to get 75 feet of #26 magnet wire on a perpendicular roof to
my window of my dorm room, and two runs of 15' speaker wire as a
counterpoise in my room. I'm getting a really bad noise problem,
however - so bad that I can't hear stations on 20 meters! There's a
pretty solid S9 noise floor that prevents me from hearing anything
other than WWV and the major broadcast stations. Now, I know I can do
better with the amount of wire I've got strung out there.

I was thinking about adding one of those 9:1 transformers or other
impedance matching things for longwires; would this reduce the noise
problem I'm having? Any other tips for reducing longwire noise? It
works enough, but I know I can do better...

Thanks in advance.

You are in a tough spot with all the computers and other electronics
around. A common mode antenna is the worst choice for you as the S9
noise floor attests.

A small active loop in the quietest spot in your room or on the roof if
you manage it would work the best. I would be surprised if a transformer
would help you much on the wire because I expect that the antenna itself
is picking up the majority of the noise. An exception to this would be
if that 75 feet of wire on the perpendicular roof is a garage and not
other rooms full of computer equipment.

--
Telamon
Ventura, California