[Elecraft] UPS Can Be a Noise Source

[Randy Farmer]

Hmmm. I had a Cyber Power 1500VA unit for a while on my station, but one 
day I transmitted on 12 meters and something inside the thing made a 
"pop". This was followed by a loud "crack" and the UPS expired then and 
there. I should note I have an extremely difficult RF environment on my 
tiny urban lot (a second floor shack with a SteppIR 3L about 15 feet 
directly over the operating chair). This might have been a one-off 
thing, but if you're going to use one of the Cyber Power devices, check 
it at LOW RF levels on all bands for EMI problems.

73...
Randy, W8FN

On 8/31/2017 4:53 PM, Jim Brown wrote:
> Perhaps by accident, I found Cyber Power branded UPS units that 1) 
> claim an 8 hour charging rate and 2) FCC Part 15 Class B compliance 
> for their pseudo-sinewave units. I have two of them in my shack with a 
> 160M vertical only 25 ft away, and with good chokes on their wiring, 
> can't hear any noise when they're in standby mode. Haven't checked for 
> noise when they're inverting.