Hi,

I'm no expert, but for whatever it's worth, I've tried
a R/S Disconne and also a Scantenna, side by side, in my attic.

The scantenna is better on all bands for my 780 Scanner.

Frankly, not by orders of magnitude better, but discernably "better".

Bob
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"asym" wrote in message
...
On Tue, 26 Oct 2004 01:41:58 GMT, Al Klein wrote:

On Tue, 26 Oct 2004 00:19:28 GMT, asym said
in rec.radio.scanner:

than at lower ones. Even "crappy" RG8 only has a loss of around 5db @
400mhz for a 100ft run. 5db is enough that you'd notice, but it's
about the smallest amount that you *could* notice.

3db is 50%, or one "S" unit - easy enough to notice. Actually, the
receiver capture ratio is the smallest amount you'll notice, so the
better the receiver, the smaller the change it takes to make a big
difference.




(If the capture ratio is, say, 2db, if the signal increases from the
noise level to 2db above the noise level, what you hear changes from
quite noisy to dead full quieting - very noticeable. If the capture
ratio of the receiver is under 1db, it takes less than 1db change to
make the above difference.)

Yes, that's absolutely true. What I mean is basically, you're going
to be in the near field for a lot of transmission sources that create
a higher noise floor than is anywhere near optimal, most of the time..
so you'll never hear those weak stations. Low loss cable will not
help in this case, because the noise is attenuated as much as the
signal. If the S/N coming in is 3:1, then it will still be 3:1 after
the cable, it doesn't matter if the cable introduces 1dB or 10dB of
loss.

If your reciever sensitivity isn't up to snuff, then a lot of times it
doesn't matter how short or long your cable run is, or if it's high or
low quality.


BTW, the advantage of a discone is that it's a good match at just
about all the frequencies we're interested in. It's not much of an
antenna - it's more of a matching device between the end of the cable
and space.

Isn't that what an antenna is really all about anyway, any kind of
antenna? Some are designed to be directional and give you some amount
of gain, but in the end, they are there to capture waves -- to
interface the cable with space.