Analog signal after digital conversion?

[Mediafrog+]

it might also be possible during the summer months and for a brief period in December, to pick up Mexican analog stations via "Sporadic E."

Actually such conditions can happen at any time, often driven by solar activity/sunspots. Here in Texas, Latin American DX is not uncommon. I'm hanging on to an old 13" B&W portable (with mechanical tuners!) to keep an eye out for low-band VHF DX from south of the border...with virtually no American DTV's in the way.

Also, as a more direct answer to your question, low powered Channel 43 in Houston formerly was used by a company called Accelernet for broadband internet and nothing was audible (or visible) beyond static on that channel (this venture did not work out long term and Channel 43 is now a Spanish news oriented TV station called TV Informa)

I never was able to discern any kind of signal on 43 when it was the Accelernet service. Maybe just a slight change in the "snow."

I think you could also ask yourself the same kind of question, if you had a very old TV set that still gets channel 70 -83. What would you get on that? I don't have one but my guess is nothing. Any cell phones or cordless phones using those frequencies would be scrambled.

15-20 years ago, when cell phones were analog, you could actually hear the phone conversations on channels 70-83. Somewhat tricky to tune in, as they were narrowband FM transmissions being received on a comparatively wideband receiver.

I got a kick out of congressional legislation at the time that banned receivers capable of tuning cell phone frequencies. Little did they realize that it could apply to tens of millions of TV sets.

The cell phone audio is now gone, with the shutdown of the old AMPS technology. I still can pick up some obvious datastreams, but they seem to be something other than cell phone services.

 

[kenglish]

I wonder how many holes the lawyers will punch in our receivers' bands when all the new stuff comes in? Of course, it's all digital, and encrypted, but I'm sure they'll still want to muck things up with restrictions.

Just give us back "full coverage" receivers and quit playing games.

 

[PhilJSmith67]

I have two older sets that tune up to 83. I can see various patterns of darker screens, occasional herringbone patterns (when two or more signals transmit simultaneously), and brighter-than-normal static. Once in a while two FM signals approximately 4.5 MHz apart will transmit and the TV will demodulate the audio -- this could be a plain FM police/fire/local govt agency, an EDACS or Motorola control channel, cellular data channel, etc. There are still many analog-FM signals between 851 and 868 MHz (channels 77-80).

South of me, Illinois Valley Cellular's AMPS system is still in operation, and I can hear the control channels with the TV, with an occasional analog-FM phone call. I guess there are still enough analog phones operating on IVC's network to warrant keeping AMPS online for now.

A previous poster mentioned that DTV signals appear as a "different kind of snow" on his set. I see exactly the same on my sets. I noticed this the first day that WFLD-DT Chicago began transmitting on Channel 31, before I had a DTV receiver, back in (I think) 1998. If you pay close attention to the type of snow, you can tell the difference between a vacant channel and one that has an ATSC signal.

 

[The Beave]

I'm hanging on to an old 13" B&W portable (with mechanical tuners!) to keep an eye out for low-band VHF DX from south of the border

We already get some crossover from Channel 8 Phoenix vs Channel 8 in Sonora, MX. I even saw it on my electronic tuner (1995) they kinda fade in and out through the overnight here in Tucson.