Not knowing were you live, Don but there were some cable boxes that emitted those same frequencies. I forget the particulars, but it was some kind of spurious radiation from the telephone interface. The cable boxes in question was manufactured by Jerrold. In some cases it would radiate voice much like a wireless phone when the owner was talking on their hard wired telephone.
Possibly a satellite receiver box? 73 Jim de W5JO ----- Original Message ----- From: "Donald Chester" <[EMAIL PROTECTED]> To: <amradio@mailman.qth.net> Sent: Saturday, April 12, 2003 1:00 PM Subject: [AMRadio] Mystery interference > > > 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 > > >
