[RFI] Re: Broadcast QRM Splatter on 6985 kHz

Scott Holisky sholisky at gmail.com
Wed Apr 7 19:18:37 PDT 2010

Hi Jim - Sounds like they maybe injecting some digital signal into the
analog transmitter. This will cause all sorts of broadband IM, I know...
There were a few TV transmitter mfg's. that thought it was a good idea for
digital tv. Well until they built a few systems and found it couldn't be

A quick way to tell if your radio, spectrum analyzer, etc. has gone into
overload is to put an attenuator in line with the input. If you see adding
10, 20 or 30 dB of attenuation drops the signal that amount then the input
isn't overloaded. If the change is dramatic, say putting in 10 dB drops the
signal 20 dB, the unit is being overloaded.

Good luck, hunt em' down, get a call sign and have at it!

73 Scott N0AR

I happened to look at the LP Pan screen that I have hooked up to a K3 and
massive splatter from a broadcast station on 6985 kHz that extends well into
40CW. The LP Pan rig is new to me, and I'm not absolutely sure that the
splatter isn't overload (although I suspect that it's not). Can someone else
take a look at this?  It almost looks like digital modulation superimposed
the analog AM. It's a religious broadcaster. Tentatively, I'd guess that
coming from S or SE of me.


Jim K9YC

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