[Premium-Rx] spikes & UPS's

[George Georgevits]

Hi Blair,

Liebert make some excellent UPS gear. Unfortunately, most of it is designed
for a computer room environment, and not for powering HF receivers. The ones
I have had experience with here in Oz were very large units, built to comply
with European EMC requirements. From the crude emission tests we performed
after commissioning, these seem to be surprisingly lax.

Anyway, try placing several ferrite clasps on the mains input lead, hard up
against the point where it enters the UPS. You will probably need quite a
few. I found this significantly reduced the high frequency currents going
back out along the mains lead, and hence the RF radiation. Try it and see if
improves your situation.

Regards,
George Georgevits

> -----Original Message-----
> I bought a top-of-the-line Liebert UPS that is fully on-line, regenerating
> a new "pure" sine wave to protect my gear. Unfortunately, the internal
> UPS power supply and the inverter both (I can hear them switch in
> separately on different frequencies) generate so much broadband rfi on HF
> as to make my Harris 590 unusable, (especially around 160 meters).
>
> The noise is coming in the antenna; if I shunt the antenna with 50 ohm
> plug the noise disappears. To listen to HF I have to switch the
> UPS to "Bypass". I wanted the UPS to keep on-air during power
> failures, so it isn't so useful. Any suggestions for fixes?
>
> Sincerely,
> Blair
>
> P.S. Just because the noise is coming in the antenna, does not
> preclude the probability that the AC power lines are acting as
> the UPS's antenna...
>
>
> Law of Logical Argument:
> Anything is possible if you don't know what you're talking about.
>
>
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