Paul,
Loading the coax with ferrites might make a difference, but I don't think
that's a good way to address the problem. If there's RF in the shack, that
probably means it's being reflected from the antenna. With or without a
ground at the shack, the antenna/load should absorb all the power you send
to it...if it's matched to the coax. So if you haven't already done this,
I'd use an antenna analyzer at the antenna feed point and see what the
match looks like there. Even if the resistive component is 50 Ohms, the
reactive part can do you in.
I have fairly good matches on two of my antennas (one an inverted-V for
160), but I find the transmitter is happier with baluns installed at the
feed points. The 160 antenna has a 1:1 and the 30m vertical (with elevated
radials) has a 4:1. The latter balun was selected unscientifically by
reaching for the nearest one on the edge of the shelf.
There are some solid technical reasons the baluns helped in these cases,
but it was much simpler to try them and see what happened. Both of these
antennas BTW are very good performers. The baluns are hand-wound using
W2FMI's excellent texts on the subject.
73,
Brad (from Tulsa)
KV5V
On Fri, Feb 17, 2017 at 1:40 PM, Paul Kiesel via Topband <
topband@contesting.com> wrote:
> Hello -
>
> I'm not able to run more than 150 watts when using JT65 on 160. RF gets
> into the computer and disrupts the JT signal. I don't have this problem on
> 6m where I run QRO using JT65 on EME. I installed ferrite beads on all
> radio and computer leads, with multiple beads on coax cables. My antenna is
> an inverted-L hanging from a big douglas fir, and it's about 150 feet from
> the shack. The feed coax is RG-218 (same as RG-17), so there was no
> opportunity to coil it into a choke at both ends. Should I be more
> aggressive with the ferrites?
>
> Respond directly, please. Thanks.
>
> 73, Paul K7CW
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