[AMRadio] Mystery interference

[Larry Will]

Sure sounds like TV set radiation to me.  Color subcarrier is 3,579.545 
kcs.  Hor rate is 15,734.26 kcs.with lower sidebands at +/- 60 hz from each 
15 kc burst.


Larry W3LW

At 07:00 PM 4/12/03 +0000, you wrote:


>A few days ago, a new interference appeared on 80m.  It consists of rough, 
>60kHz modulated carriers, spaced at 15.7325 kHz intervals.  At first I 
>thought it might be a touch lamp, but the carrier frequencies are 
>extremely stable, despite the rough sounding modulation.  The strongest 
>carrier appears to be at 3579.55 kHz.  Carriers are clearly audible from 
>3406.48 kHz to 3736.9 kHz, with vestiges detected above 4 mHz.  The sound 
>of the modulation changes every few seconds, and the signal strength 
>varies as the modulation changes.  At its strongest point it is about 10 
>dB above S9.  I get the strongest signal on the 160m. beverage, but it is 
>audible on the 10m. ground plane and indoor loop.  The signal is weakest 
>on the transmitting dipole.
>
>I measured the frequencies using a DDS vfo with 1 Hz 
>resolution.  Individual frequencies may be inaccurate due to the 
>difficulty in finding zero-beat in the presence of the rough 60Hz 
>modulation, but the spacing of the signals was determined by averaging the 
>difference in measured frequency between adjacent carriers throughout the 
>band.  At the time, the DDS vfo was zero-beat with WWV at 10 mHz.
>
>Readings were taken at the following frequencies:
>
>3500.88
>3516.662
>3532.25
>3548.15
>3563.69
>3579.55
>3595.29
>3611.02
>3626.74
>3642 (approx)
>3698 (approx)
>3674 (approx)
>3690 (approx)
>3706 (approx)
>3721 (approx)
>3736.9
>
>
>I am hoping someone might save me from having to re-invent the wheel in 
>chasing down this interference, by identifying a probable source based on 
>the above data.
>
>73 de K4KYV
>
>
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