When I was building the 2 station operation here I tested a wide variety of
flexible coax looking for the best null. CATV RG-11 was the best, giving a
solid 25dB+ null, The impedence doesnt matter. I would suspect the the LMR
would be similar in performance.
A very easy way to tune the stub is to cut it a bit long, hook it to your
receiver thru a T connector and with a noise bridge simulating the antenna.
Spin the RX dial back and forth and note the frequency of the deepest null.
Then trim until you have it centered exactly where you want it. On 80/160
you could use vacant band noise in the middle of the day.
Carl
KM1H
----- Original Message -----
From: "Robert Pack, NX5M" <nx5m@txcyber.com>
To: <towertalk@contesting.com>
Sent: Tuesday, July 17, 2007 9:18 PM
Subject: [TowerTalk] LMR240 for stub filters?
> Wondering what the group thinks about the use of LMR240 as stub filters
> for the 80 and 160 stations here. I have a bunch of it that I am not
> going to use for anything so if you guys think it would work for this
> purpose at least I can use it for something constructive.
> This stuff would be used behind 1500w amps. I know that someone has
> melted down stubs made of RG58 which is pretty much the same as LMR195. I
> believe LMR240 has a higher power rating than RG58 (which I would never
> use anyway) so this got me to thinking that 240 might work.
> What do you guys think?
>
> 73,
> Bob NX5M
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