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Loggings => Other => Topic started by: ChrisSmolinski on September 11, 2012, 1233 UTC

Title: Odd Signal / QRM 43 meters 0858z
Post by: ChrisSmolinski on September 11, 2012, 1233 UTC

This is something I have noticed for many months, since I started recording overnight on the SDR. I think the waterfall shows it best:

(http://www.hfunderpants.com/mypics/OddQRM.jpg)

Time runs down, ie: it starts at the top of the image, at about 0858z, and stops about 2/3 of the way down, at 0905z.

This signal appears roughly around this time (0900z is presently 5 AM local time), I'll need to more carefully observe when I notice it, to see if it is really following any kind of a schedule.  It sure looks like a switch mode PSU of some kind. It's only on for a few minutes, and I don't seem to notice it at other times of the day. Any ideas?

Title: Re: Odd Signal / QRM 43 meters 0858z
Post by: cmradio on September 12, 2012, 0506 UTC

Very clean lines. Harmonics are too perfect for a SMPS, which would be stronger of the odd harmonics (square wave).

Vat ees dat? ???

Peace!

Title: Re: Odd Signal / QRM 43 meters 0858z
Post by: ChrisSmolinski on September 12, 2012, 1042 UTC

It appeared again this morning, from 0842z to 0852z. The pattern looks almost the same, the difference is that since it was on for a longer time, the drift in the frequencies near the end is less (the lines are closer to vertical, but still slanting/drifting some)

Title: Re: Odd Signal / QRM 43 meters 0858z
Post by: refmo on September 12, 2012, 2200 UTC

Coffee maker would be my guess.....