It may be the EAS channel feed at channel 97. It isn’t usually mapped to receiver guides, but this could be the channel that overrides your cablebox. Next time you have some bad weather days, hook it up and monitor that channel during an alert. Ours used to say EAS DETAILS CHANNEL for the longest time.
So that gap around 430mhz you are seeing is where the AGC (automatic gain control) or "pilot" channel used to be before your area went midsplit. So when an amp would be balanced (levels set correctly) you flip a switch and the amp locks on to that frequency and when the temperature changes the AGC does its best to turn itself up and down to maintain those set levels. That's the basics of what's happening. When the midsplit happened that frequency was no longer needed as the new amplifiers have an AGC that lock onto a frequency that is set inside the OFDM. Hope that helps.
I really enjoyed this video. It explained a lot that I was wondering about. Have you given consideration to creating a video on how one could use the RTL-SDR USB and Spektrum to analyze 'noise' interference on an internet cable? I can imagine how this would be useful to many people, and certainly to me. I would love to be able to conduct my own analysis and compare it to what Spectrum Field Technicians are telling me. Keep up the good work!
I wonder if the analog carriers are really an artifact from the old days, or perhaps related to diagnostics. I recall that my local cable provider used a channel around Ch. 60 as a sort of monitor transmitting a video feed of a Debian terminal
Perhaps diagnostics, though I was thinking it was strange they appeared completely unmodulated in Spectrum (no data going over them) and a were just black screens on my TV (during the few instances I looked at them, of course). Maybe they are there to provide reference signals for technicians to diagnose line issues.
I'm so old that I remember when 439.25 MHz was the output of the ATV (amateur television) repeater in Arlington, Virginia back in the 1980s. Although ham radio is secondary use in that band, I'm sure hams appreciate not having broader bandwidth leakage to deal with LOL. Interesting video, thanks.
Sorry for a noob question, but what is the point of all this. Are you just seeing what you can receive off of your coax cable system? Is this an alternate type of antenna? Thanks.
Basically just seeing what I can receive off of my coax cable system. Here all the channels are encrypted, but in some cases you might find some channels, like locals unencrypted. That seems to be becoming more rare, though. I have also used the spectrum analyzer software to check if a coax is active or to troubleshoot issues.
