Why does this work?
I'm really new to SWL and obviously have a lot to learn. So I'd like to try
to understand what I need to receive what radios like the Grundig 400PE and
Sangean 803A are capable of receiving. I use both, but find the Sangean more
"fun" because it has a tuning knob. There is something about a tuning knob
that feels better than a button to go to a frequency. Perhaps its because
its more like that old radio I used to play around with when I was a kid
back in the early 50's.
In any case, since its winter here in Illinois I have put off any attempt to
put an antenna outdoors. The situation is this: aluminum sided home, shack
in the basement about four feet from my laptop computer. About 15 years ago
I ran an RG59U cable from the attic to the basement; its been unused for
most of those years, but recently I ran a 40 foot length of #14 single
stranded, insulated copper wire lengthwise in the attic. It is stapled to
the rafters about three feet down from the peak. I soldered the center
conductor of the RG59U to the end of the copper wire. The cable runs down 25
feet vertically to the basement and is connected to the whip antennas of the
radio with an alligator clip, since the radios do not accept the same plug.
(The wire in the attic runs essentially NNE to SSW and the downlead cable is
soldered to the NNE end of the wire. the SSE end takes a right angle with
the last 6 feet of wire. So it takes the following shape:
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|------------------------------------- (Downlead
side) NNE
This setup left me able to receive more than I could with about 25 feet of
multistrand, speaker wire tossed out the basement window and anchored up in
a tree next to the window, but it is noisy. Lots of static, but turning off
various things (computers, fluorescent lights, dimmers, etc.) doesn't seem
to reduce the noise. I noticed that when attaching the antenna to the whip,
I was getting pretty good reception and less noise when the alligator clip
was about two inches from the whip. For some reason I decided to wrap about
50 loops of the #14 insulated wire around a piece of 1 1/2 inch PVC pipe
and bare one end of the coil for attachment to the alligator clips. I
slipped the coil over the whip, attached the clip to the bare portion of the
wire forming the coil and I get pretty decent reception with less noise that
with the clip attached directly to the whip. Clipping the alligators to the
insulation on the end of the coil I get even less noise, and still pretty
decent reception.
Why does this work? Is there anything else I can do with the current setup
to improve things? Until spring arrives I'm not even going to think about an
outside antenna. What mistakes did I make? How is the current setup going to
limit reception on various bands? How will it improve reception relative to
just the whip (which is kind of useless in the basement, anyway)?
Did I do anything right? Did I do anything wrong? I see SWL as essentially
experimenting with antenna configurations. Is this a valid way to look at
it?
Harlan
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