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

Fri Oct 3 10:26:50 EDT 2008

Hi, Well I sure appreciate the help. I found the offending TV. Next door to 
my house at a group home for disabled people. What are my options with this? 
I dont think they will be very receptive to me asking them to do something. 
Not sure yet. I know they wont let me put any ferrites on. Thanks- John 
W9RPM
EMAIL: john at w9rpm.com
WEBPAGE: http://www.w9rpm.com/
AOL IM: W9RPM
YAHOO: W9RPM

----- Original Message ----- 
From: "WX5L" <wx5l at charter.net>
To: "RFI" <rfi at contesting.com>; "W9RPM" <john at w9rpm.com>; "Lefczik, Larry D" 
<larry.d.lefczik at lmco.com>
Cc: <tvi-rfi-emi at mailman.qth.net>; "w1rfi" <w1rfi at arrl.net>
Sent: Thursday, October 02, 2008 12:51 PM
Subject: Re: [RFI] [TVI-RFI-EMI] Noise every 15Khz on 17M

> 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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>> >
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