[RFI] Noisy Uninterruptable Power Supply (UPS)

[Wes Stewart]

 I thought about one of these to keep my frequency standards powered during power outages until I read the 5% 1-star reviews on Amazon:  https://www.amazon.com/product-reviews/B00429N19W/ref=acr_dp_hist_1?ie=UTF8&filterByStar=one_star&reviewerType=all_reviews#reviews-filter-bar
Wes  N7WS



    On Monday, June 12, 2023 at 03:18:26 PM MST, Jim Brown <jim at audiosystemsgroup.com> wrote:  
 
 On 6/12/2023 12:50 PM, RVZ via RFI wrote:
>   I'm wondering if there is a commercially made UPS (Uninterruptable Power Supply) that is RF quiet, or more RF quiet, than the average?

Yes, the CyberPower CP1500PFCLCD. I have five of them, first bought at 
least ten years ago. In addition to being relatively quiet when in 
standby mode, it has the MAJOR virtue of not overcharging the battery, 
causing the battery to last a long time. Most UPS units DO overcharge 
the battery, so you have to buy a replacement (from them, of course) 
every year or two.

With ANY modern power supply, it's good practice to wind multiple turns 
of the power cord through a big #31 clamp-on. Detailed advice in this 
applications note.
http://k9yc.com/KillingReceiveNoise.pdf
and this slide deck.
http://k9yc.com/KillingRXNoiseVisalia.pdf

73, Jim K9YC
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