Thanks for your thoughts. I looked at things here just now, and found that
(1) unplugging my amplifier's power cord and (2) disconnecting an unused
50' run of RG-213 from my main TX antenna switch drastically drops that
noise. :-)
I thought the noise pickup was somehow related to the low F/B (10 dB) of my
NE-SE Beverage. That now appears to be a different issue --to be solved
another day, since it's still considerably superior to the inverted-L for
receiving.
73, Mike
www.w0btu.com
On Sun, Mar 2, 2014 at 8:27 AM, Tom W8JI <w8ji@w8ji.com> wrote:
> I'm not saying that there's not a case for suppressing common mode as you
>> and others suggest.
>>
>
> It all comes down to impedance ratios and signal levels. Any choke or
> filter is like a pi network or attenuator pad. It is ***always*** more than
> the series element alone.
> ...
>
> I do have a problem here lately with RFI from an electronic fluorescent
>> ballast on 160 (10 feet from where I operate the radio), and I'm not sure
>> how it's getting into my NE Beverage. Big #43 beads on the ballast leads
>> didn't fix it. But that's another story.
>>
>
> There are two forms of noise egress, common mode and differential mode.
> ...
> It seems very few people look at the system, which isn't that hard to do.
>
>
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