[RFI] Inbound RFI - strange source affecting 160 and 80

Stu Phillips stu at ridgelift.com
Sun Feb 21 15:07:59 PST 2010

I'm wondering if anyone has seen an RFI source like this before?

* At isolated (and generally short) periods, the RFI is gone. 
* It has two modes... 
* Mode A - like the pattern from my first RFI Hunters post, a repeating
pattern every 18 KHz with a central noise "splodge" about 3-4 KHz wide
with two "sidebands" equally spaced +/- 5 KHz from the center of the
* Mode B - a 500 Hz "spoldge" of noise repeated every 18 KHz 
* Both modes appear to have multiple "sub-carriers" within the noise -
it's hard to tell but it appears that these carriers carry some form of
* Both modes exhibit excellent frequency stability 
* Both modes deliver about -76 dBm into my receiver - that's around 35
micro-volts - pretty hot! 
* Some patterns have emerged... typically early in the morning before
7am, mode B is present. It has transitioned to mode A several times at
7am and continued in this mode until about 9am. Then it reverts to mode
B. At the weekend, its often in mode A all day long... 

More information about the RFI mailing list