On Tue, 05 Apr 2005 10:01:20 GMT, Gunner
wrote:

Over the weekend, I stumbled into a Panasonic RF-4800 general
communications receiver. It looks like it just came out of the box.
Mint+.

I have some issues that perhaps some of you can help with.

First of all, as some of you know, I spend most of the week working
out of an RV in an RV park. The park rules are such that they really
frown on antennas other than TV. So it leaves out a long wire antenna.
My TV antenna (no cable in the park) is about 12' to the yagi. So I
have a mounting height issue..the Slinky trick is out.

Anyone got a good suggestion for a low profile antenna that will cover
broadcast to 31 mhz? Vertically polarized, or
horizontally..horizontal would be best. The RV has a surface aprox 7'
wide by 20' long.

loop antennas are out. No way to turn it from inside and are a bit
high profile.

Second big question. The only place to put this receiver is within 3
feet of my computer. So Im getting freaking huge birdies all over the
spectrum with the puter/monitor turned on.

The receiver has a 50ohm Pl259 coax connector, as well as a binding
post for a long wire. Plus a binding post for AM broadcast and a
third for FM broadcast.

The RV itself is a damned good Faraday cage. Aluminum siding, aluminum
window frames and screen. Even the local stations fade to zip when
the door is closed. I have to leave the cell phone near a window to
work. So the antenna has to be external. Shrug.

Anyone got any suggestions? Ive got a chunk of wire tossed over the
roof at the moment, but tis not particularly effective.

Stealth antennae are very site and situation specific. Think camou:
use your ingenuity to devise a conductor of some extent that looks
like something the rules don't forbid or is invisible because it looks
like something familiar. Flagpoles, cutesie picket fences,
clotheslines, a rabbit hutch made of chickenwire, decorative
low-voltage lighting as is often used on RV's, etc etc.

Electrically short antennae have very very low radiation resistance,
so a tuned matching network can make a big difference. I disagree
with the poster that said they are only suitable for transmitting,
though I will agree that once you reach atmospheric noise threshold
then further gain t without directionality is of little benefit.

The matchbox would need to be tuned along with the rcvr. Tune for max
noise from the radio at the freq of interest. A simple JFET preamp
may help, or not, depending on the sensitivity of the radio. If the
radio has a 3-gang tuning cap then it already has a tuned RF stage.
If it doesn't, then a preamp will help.