[RFI] [TVI-RFI-EMI] Noise every 15Khz on 17M

[WX5L]

John,

The dead give-away is the frequency seperation of 15 khz. You are hearing the horizonal sweep noise produced by a television(15.75 khz) in your close proximity. 
Often this sweep noise will couple with the cable and/or the electrical line and radiate outbound. It depends on the manufacturer on the severity of the problem. It could also be a poor cable connection aggravating this situation. 

 If the connections are good there's not much you can do about it but try and choke the cable or electrical line with feritte core's. I have used mixture 77 with some success but it's hard to remove all traces of this wideband harmonic of 15.75 khz produced by the TV. 

With a portable shortwave receiver preferably with a SSB detector so it can most resemble what you are hearing on your HF you need to hunt this TV down by walking the street. Once you've focused down to a few houses then walk up to the cable entrance or meter pan for closer inspection. You may need to collaspe the telescoping antenna to detune the antenna as now this noise will be loud.

Once you've found the offending TV convincing the owner will be another challenging which may be more difficult than finding it.

Good Luck,
Randy
WX5L
--


WX5L
Thibodaux, LA

---- W9RPM <john at w9rpm.com> wrote: 
> Hi Larry,
>                 Yes it occurs on all HF receivers.
>                 It occurs on all antennas.
>                 Does not occur with antennas disconnected.
>                 Does occur on an HF mobile when I drive away.
>                 It is a carrier, wide band I would say. Almost like a 
> buzzing sound.
>                 It is there about 80% of the time.
>                 Signal strength is constant when there.
>                 It is the strongest to the east of me.
>                 There are houses, a gas station, and Wal-Mart to the 
> east/southeast of me.
> 
>                                     Thanks for asking the questions. Helped 
> me explain it hopefully better.   73 John
> EMAIL: john at w9rpm.com
> WEBPAGE: http://www.w9rpm.com/
> AOL IM: W9RPM
> YAHOO: W9RPM
> 
> 
> ----- Original Message ----- 
> From: "Lefczik, Larry D" <larry.d.lefczik at lmco.com>
> To: "RFI" <rfi at contesting.com>
> Cc: <tvi-rfi-emi at mailman.qth.net>; "w1rfi" <w1rfi at arrl.net>
> Sent: Thursday, October 02, 2008 9:15 AM
> Subject: RE: [TVI-RFI-EMI] Noise every 15Khz on 17M
> 
> 
> >I think you need to provide more detail.
> >
> > Does it occur on all HF receivers in the shack?
> > Does it occur on all antennas?
> > Does it occur without an antenna connected to the receiver?
> > Does it occur if you take an HF receiver mobile and drive away form the
> > shack?
> > What do you mean by noise?  Is it a carrier?  Is it wideband white
> > noise?
> > It the interference there 24/7?
> > Is the strength constant?
> > What other info can you provide?
> >
> >
> >
> >
> > -----Original Message-----
> > From: tvi-rfi-emi-bounces at mailman.qth.net
> > [mailto:tvi-rfi-emi-bounces at mailman.qth.net] On Behalf Of W9RPM
> > Sent: Thursday, October 02, 2008 10:03 AM
> > To: RFI
> > Cc: tvi-rfi-emi at mailman.qth.net; w1rfi
> > Subject: [TVI-RFI-EMI] Noise every 15Khz on 17M
> >
> > HI, I am looking for some help on finding a noise that is up to s9+
> > every
> > 15Khz on 17M. The loudest is on 18125, then it drops off slightly every
> > 15Khz from 18125. Thanks- John W9RPM
> > EMAIL: john at w9rpm.com
> > WEBPAGE: http://www.w9rpm.com/
> > AOL IM: W9RPM
> > YAHOO: W9RPM
> >
> >
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