On 3/29/2018 7:16 AM, Chris wrote:
That's what I hear as well...birdies spaced evenly across the band(s). Not s9
or anything like that, but still real annoying!! I guess that is the price we
pay for modern technology.
How is that dish getting its power? If via the Ethernet cable, my money
would be on that as the source of these birdies. The wall wart that
powers it is probably a switch-mode supply, and the Ethernet cable is
its transmitting antenna.
These are NOT Ethernet birdies -- they are stable, modulated carriers
around 14,030 kHz, 21,052 kHz the low end of 10M and 6M. There are two
that show up on 30M. There are probably others, but because I'm a CW op,
these are the ones I run into. If you have neighbors, you'll hear their
birdies too, slightly displaced in frequency from your own, because each
router has its own crystal. The Ethernet cable is the transmitting
antenna, and electronics at both ends of the cable are the transmitters,
so both ends need a serious ferrite choke.
If you haven't already done so, take a look at
http://k9yc.com/KillingReceiveNoise.pdf ; which addresses how to identify
noise sources by type, track them down, and suppress them. Also, NK7Z's
website has lots of very useful info, including spectrum plots of
various noise sources. He also shows an excellent method for tracking
them using a spectrum display running 24 hours!
73, Jim K9YC
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