I've had a bit more time on my hands during the holidays to keep looking into this and WVNY continues to come and go. In my location, in Saint Laurent, it seems fair to say I receive the channel no more than 30-40% of the time.
A family member has lent me a software-defined radio (SDR) : this essentially combines an oscilloscope and radio scanner to run on the computer, with a hardware dongle to feed the antenna signal. I took a few measurements in the 174-180 MHz vicinity and what I've found was interesting.
Image 1
WVNY was rock-solid today just after lunch time. The ATSC pilot broadcasts on 174.3 MHz and showed an apparent power of -31.4 dB. Notice the blip at 175.016 MHz on the scope screenshot. Its apparent power was at -44.4 dB and was not in the way of solid, pixel-free reception.
Image 2
Then early in the afternoon, before 2 PM, this 175.016 MHz "tone" grew much louder and reached -19.1 dB in apparent power. I tuned it in with narrowband FM modulation and it hears like a steady tone. WVNY was not watcheable at this time. Notice how the ATSC pilot apparent power is near-identical to the lunch-time power-reading.
Image 3
As a control measure, I tuned to WFFF on 482 MHz. WFFF always comes in strong for me and is not problematic. The ATSC pilot apparent power is -30.1 dB which is right where WVNY comes in. No RF interference was found across the 6MHz channel spectrum.
My takeways:
Since my SDR rig is mobile (runs on laptop), I'll take a few readings around town to determine how local this interference is and will share back here.
I'm just glad I can finally stare at the WVNY reception problem. Fixing it is another step of course.
A family member has lent me a software-defined radio (SDR) : this essentially combines an oscilloscope and radio scanner to run on the computer, with a hardware dongle to feed the antenna signal. I took a few measurements in the 174-180 MHz vicinity and what I've found was interesting.
Image 1
WVNY was rock-solid today just after lunch time. The ATSC pilot broadcasts on 174.3 MHz and showed an apparent power of -31.4 dB. Notice the blip at 175.016 MHz on the scope screenshot. Its apparent power was at -44.4 dB and was not in the way of solid, pixel-free reception.
Image 2
Then early in the afternoon, before 2 PM, this 175.016 MHz "tone" grew much louder and reached -19.1 dB in apparent power. I tuned it in with narrowband FM modulation and it hears like a steady tone. WVNY was not watcheable at this time. Notice how the ATSC pilot apparent power is near-identical to the lunch-time power-reading.
Image 3
As a control measure, I tuned to WFFF on 482 MHz. WFFF always comes in strong for me and is not problematic. The ATSC pilot apparent power is -30.1 dB which is right where WVNY comes in. No RF interference was found across the 6MHz channel spectrum.
My takeways:
- My antenna and pre-amp setup receive the WVNY signal just fine;
- Reception is hindered by interference from an unknown source on 175.016 MHz.
Since my SDR rig is mobile (runs on laptop), I'll take a few readings around town to determine how local this interference is and will share back here.
I'm just glad I can finally stare at the WVNY reception problem. Fixing it is another step of course.