[TowerTalk] Slightly off-topic

[Jim]

Simple.

Inductive coupling between the brake transformer in the rotor control 
box (which is pretty large) and a transformer in the filter. It can also 
be a ground loop, but most likely as above.


Thanks
73
Jim W7RY

On 2/8/2019 9:53 AM, Brad Anbro wrote:
> ​Hello all,
>
>
> I have a problem which has me completely baffled. I am attempting to use
>
> a Bencher "XZ-2" audio filter, in conjunction with my early-model Yaesu
>
> FT-1000MP. When I move my HF antennas with the control box that powers
>
> a Tailtwister rotator, I get a very loud 60-Hz hum in my headphones. Even
>
> when I only depress the brake release lever on the control box, it still
>
> produces a hum.
>
>
> So far, I have tried electrically isolating the grounds for both the rotator
>
> control box and the Astron DC power supply, which supplies DC power to
>
> the audio filter (and other devices). None of this has helped.
>
>
> I have found that if I plug my headphones directly into the headphone jack
>
> of the HF rig, there is no hum whatsoever. I am guessing that the 60 Hz
>
> AC is coming into the audio filter through the DC power supply cord. If
>
> this is actually the case, I don't know what to do about it to solve the
>
> problem.
>
>
> Any ideas or help with my problem would be most welcome. Thank you!
>
>
> 73,
>
> Brad Anbro, N9EN
>
> Bluff City, Tennessee
>
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