I recently relocated temporarily to an urban apartment in Towson, MD. I
set up my active vertical antenna outside a window, and was really
surprised by how high the noise level is.
I've put an SDR view of about 200 KHz at
<https://www.dropbox.com/s/op4t1wa8erk5k7v/Noise%20signature.png?dl=0)>. You'll
notice that the noise floor at 14 MHz is around -100 dBM, compared to
-120 at my rural QTH, and at some other frequencies the noise floor is
as high as -70 dBM.
I'm used to line noise, but the thing that strikes me about this is the
noise peaks that occur every 60 KHz. On AM, they sound like arcing, with
a pronounced buzzing sound. There's also a "meta-period" to the noise -
it is much worse at some frequencies than others - there are very broad
noise peaks at around 5 and 10 MHz, and "valleys" at 14 MHz and elsewhere.
Does anyone have any ideas from this "signature" what I might be dealing
with here? I'm in a bit of a "stealth" situation here, which tends to
put a crimp in any thoughts of DFing with a VHF receiver and my 136-MHz
Moxon.
--
73, Pete N4ZR
Download the new N1MM Logger+ at
<http://N1MM.hamdocs.com>. Check
out the Reverse Beacon Network at
<http://reversebeacon.net>, now
spotting RTTY activity worldwide.
For spots, please use your favorite
"retail" DX cluster.
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