Topband: Nasty QRM From ??

[k8bhz at alphacomm.net]

Just a thought, does your house have the new "intelligent" power 
metering on the powerline? This would still be on, even if your breakers 
were off. Or, maybe the same type of monitoring on natural gas or 
municipal water supplies. Sure sounds like a switching power supply....

Brian  K8BHZ

On 1/24/2020 1:59 AM, Dick Bingham wrote:
> Greetings All
>
> Here are my basic conditions:
> - KiwiSDR (~DC-to-30MHz) or
> - Apache-Labs 7000dle
> - Dell laptop computer
> - Both on battery power
>
> I have cleaned up my system using chokes and filtering to the point
> there are virtually no CM-signals entering the receiver when the feedline
> at the antenna is disconnected and re-connected to a 50-ohm load.
>
> When the antenna is reconnected I see desired signals PLUS an
> unwanted comb-line with signals every ~98.4KHz (e.g. comb-lines span
> 2573.49KHz to 4355.38KHz resulting in 98.438KHz line spacings.)
>
> These signals are frequency stable and not drifty. Shutting down the
> house-mains with the receiver battery powered does not kill the QRM.
>
> SO, it looks like something somewhere is generating this junk that runs from
> the BC-band to >20MHz.
>
> Have any of you encountered similar ~98.xxxKHz spurious signals ?
>
> 73  Dick/w7wkr at CN97uj
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