[600MRG] RFI identified

[Renee K6FSB]

I had same/similar issue extended up into HF and found a simple 20Amp 
Line filter did the trick for me. I had found it in a surplus store ( 
like in 2000) and had it for a rainy day....when I replaced the fridge 
the issue started...old 1970 fridge = no issues , new 2005 fridge  
needed filter.
same thing for some of the led replacement florescent bulbs, they may 
need rfi proof...some companies cheap out..there is a place on their 
board but no parts....
Renée, K6FSB


On 1/3/25 9:13 AM, Brian Pease wrote:
> Experimenting is in order. One thing you could try, *with care*, is to 
> plug in the fridge with a cheater adapter that isolates the frame from 
> ground to see if that helps. As a next step, ground the frame to 
> something other than the power line 3rd wire. Another thing would be 
> an old school 60Hz isolation transformer, although I have found there 
> tends to be too much capacitance between windings. A transformer with 
> a groundable shield between windings might work. You could try a UPS 
> if you had one large enough, but of course they can be their own 
> source of RFI.  Then it is on to the line filter option.
>
>
> On 1/3/2025 11:47 AM, Paul N1BUG FN55mf wrote:
>> Since my return I have been plagued by periodic RFI that reduces S/N on
>> 630m by 10 to 15 dB, maybe more at times. It tends to cycle on for one
>> to three hours, then be off for a few to several hours. Audibly in AM
>> mode it is a somewhat rough 120 Hz buzz. Noise blankers don't touch it.
>> I can identify this RFI from below 10 kHz to above 500 kHz, but there
>> are several broad peaks and valleys across the range. The worst of them
>> is very broad centered approximately on 450 kHz but remaining almost
>> flat up to and across 630m. I have not tried to find the upper frequency
>> limit since I really don't care about anything above 500 kHz.
>>
>> Early this morning I found it the culprit. It is my refrigerator!
>> Perhaps a line filter will help, although my luck is rarely that good.
>>
>> I'm still chasing one, possibly two serious RFI sources affecting 2200m
>> but won't go into that here.
>>
>> 73,
>> Paul N1BUG
>>
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