[Lowfer] [EXTERNAL] Strange QRM here on SAQ frequency

[jrusgrove at comcast.net]

Bill

Can you send a short audio clip?

Jay W1VD


----- Original Message ----- 
From: "Bill de Carle" <ve2iq at magma.ca>
To: "Discussion of the Lowfer (US, European, &UK) and MedFer bands" <lowfer at mailman.qth.net>
Sent: Tuesday, July 01, 2014 11:45 PM
Subject: Re: [Lowfer] [EXTERNAL] Strange QRM here on SAQ frequency


> Thanks Laurence.  No cable TV in this area but I guess the 
> interfering signal could be from some kind of switching supply.  I 
> have difficulty with the narrow emission bandwidth and the observed 
> frequency stability.  Local phone company runs DSL here over some 
> distance so they must have repeaters.  Strange how the signal 
> disappears completely from time to time like equipment was switched off.
> 73,
> Bill VE2IQ
> 
> At 08:58 PM 7/1/2014, Laurence KL7L wrote:
>>Looks like switched mode- get the same from cable company head end 
>>amp power supplies in road side cabs - comes and goes
>>
>>Laurence kl7l
>>
>> > On Jul 1, 2014, at 4:45 PM, "Bill de Carle" <ve2iq at magma.ca> wrote:
>> >
>> > Hi Everyone:
>> >
>> > Anyone on this reflector know what could cause some very strong QRM I
>> > see right on top of SAQ's 17.2 Khz frequency?  It consists of a group
>> > of spectral lines spaced 120-Hz apart, centered near 17.2 Khz but
>> > occupying only about 1 KHz bandwidth.  This QRM is present most of
>> > the time at my QTH but oddly enough, it wasn't there on Sunday
>> > morning when I got up around 4:30 am Eastern time.  Obviously it's
>> > powerline-related, but as far as I know (famous last words!) it
>> > doesn't seem to be coming from anything in my home.  I can even
>> > disconnect the mains & run on batteries: the signal does not change,
>> > so it is clearly radiated, not conducted through the power line.  The
>> > amplitudes of the individual spectral lines vary slowly (cycling over
>> > perhaps 20 seconds), seemingly at random.  I live in a rural
>> > neighborhood and there are some electric fences around.  What bugs me
>> > is why at 17.2 Khz?  Have you seen this signature before?  Here's a
>> > screenshot showing what it looks like:
>> >
>> > http://www.magma.ca/~ve2iq/saq_qrm.gif
>> >
>> > Any ideas would be much appreciated.
>> > 73,
>> > Bill VE2IQ
>> >
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