[RFI] 48v DC Clean Power Supply

[Chuck Gooden]

Jim,

I am having the similar issue at ~3.588 Mhz  issue.   If you have a 
small radio the noise should be readily found near this freq. It does 
drift slightly when the switch is first turned on

I replaces the supply for my Unifi US-8-60 switch with a 48V 3 amp 
Linear open frame power supply(P/N HD48-3-A)  made by Condor that I 
purchased on Ebay for $20.00.  The power supply made little if any 
difference in my system.  There is apparently another switching supply 
inside the switch to reduce the 48V to a lower voltage for the switch 
circuitry.  Putting in a cheap netgear switch will fix the issue, but I 
lose my POE to power my wifi access points.  Both of my Unifi switches 
have this issue with a slightly different frequency.  I like the Unifi 
network and am currently living with the issue at the moment.

See: 
https://www.ebay.com/itm/Condor-HD48-3-A-Power-Supply-Board-48v-DC-Output-30-Day-Warranty/303451909858?hash=item46a724aee2:g:vWQAAOSwaENd1qco:sc:USPSPriorityFlatRateBox!61107!US!-1

I also have snap on #31 ferrites on all cables connected to the switches.

After I get my other PC built and my NAS working and online, I planned 
on contacting the manufacture of the issue and see what they can do.  I 
do nothink they will be able to do much though. So I may be forced to 
replace the switches

Please keep me in the loop if you find out anything.

73's

Chuck K9LC


On 3/25/2020 10:50 AM, Jim McCook wrote:
> My neighbor is throwing RFI out that affects 15 and 10m bands.  We 
> finally traced the source to a Unifi US-8-60 internet switch that uses 
> a separate 48v power source.  Naturally it's a dreaded switcher, so he 
> needs either a clean switching supply (if it exists!) or a analog 
> supply.  I'm unable to find anything resembling a wall wart style.  
> Can anyone suggest a solution? These internet switches are showing up 
> much faster now and represent a big potential problem, compared to the 
> typical router operating at 5v with the 14.029 noise.  Jim W6YA
>
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