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eHam Forums => Elmers => Topic started by: NB9N on July 20, 2012, 03:33:33 AM



Title: 60 khz birdies
Post by: NB9N on July 20, 2012, 03:33:33 AM
Could someone tell me what are those annoying "birdies" I am receiving all across the 20 meter band?   They are spaced approx 60 khz and the signal is horizontally polarized.  I have checked all my devices in the house and it also plays on my other radio as well.   The signal is approx s-8 in al most any direction...

Joel


Title: RE: 60 khz birdies
Post by: WA3SKN on July 20, 2012, 04:28:41 AM
Most probably some sort of local interference.  Do you get them with a dummy load?  If not they are incoming via the antenna, and you will need to DF them.

-Mike.


Title: RE: 60 khz birdies
Post by: KA4POL on July 20, 2012, 05:23:07 AM
Could you power your equipment from a battery? Switch the circuit breakers in your house off one by one. This will show you if you are the one who is to be blamed.


Title: RE: 60 khz birdies
Post by: AC5UP on July 20, 2012, 06:56:27 AM
Any smart appliance with a switchmode power supply or processor chip can do that, and CFL lamps have an electronic ballast operating in the 40 to 60 kHz range. Rare that a CFL lamp would be that loud on harmonics unless very near the antenna or it's an older lamp going bad. Prime suspects would be anything large enough to radiate Q-5 (like a plasma TV) or something with a fair amount of wire it can couple into... Like a satellite TV box.

As mentioned previously, step one is to shut down your entire house to determine if the noise is internal or external. If internal (no power = no noise) bring up each individual circuit in your breaker box one by one until the noise returns. That should narrow down the source to a few devices. I know you checked everything in the house, but some things are easily overlooked. Like a porch light, nightlights, cable (or DSL) modem and router. The breaker box misses nothing.

If the noise source is external to you, think of this as a golden opportunity to learn the arts of direction finding by triangulation and public relations.    ::)


Title: RE: 60 khz birdies
Post by: KA4POL on July 20, 2012, 07:13:44 AM
Is there a wireless router?


Title: RE: 60 khz birdies
Post by: NB9N on July 20, 2012, 11:59:44 AM
Tnks for the possible sources.  will get to it when i get back from vac.   73s


Title: RE: 60 khz birdies
Post by: NB9N on July 21, 2012, 04:38:09 AM
The interesting thing is that when I switch to my 43' vertical loacated 180 feet from my station the noise is gone (except for line noise)  Switching to the dummy noise removes much but still clearly there... So it still appears to be a horizontal polarized noise. However I have yet to check my bridge and router..


Title: RE: 60 khz birdies
Post by: NB9N on July 21, 2012, 04:40:59 AM
 ::)  Yes it WAS the (router/bridge) setup!

Thanks again
Joel/ NB9N


Title: RE: 60 khz birdies
Post by: KA4POL on July 21, 2012, 06:43:35 AM
Something to keep in mind for the future. Thanks for the feedback.