Hello there. Apologies if this is an FAQ or covered in documentation somewhere. I've spent a while looking/searching and so far have not found any documentation on this. It would be great to hear from the experts here on how Tivo's channel setup code is supposed to work. I have a Bolt (new as of two days ago, firmware updated post-install) that I am using in OTA mode.
Some background: I live in a place that has fringe OTA signal reception, however I have the antenna and preamp aspect covered (I'm a EE). On a regular TV I am able to scan for digital channels, pickup all the major networks, and view them. This isn't a question about signal strength but rather what the Tivo software does in the realm of channel scan and setup. Perhaps also significant, I live in a place where ZIP codes are very large (Montana) and also between two TV markets. So to answer the question "what set of TV channels might you be able to receive", having only the ZIP code is really not too useful.
So, first let me describe what a regular TV does in its channel scan:
1. For each physical channel in the broadcast bands, listen for an ATSC transport stream. If one is decoded, extract the virtual channel ident information.
2. Display the list of virtual channels, ident text, and (usually) physical channel for the user to review.
Here's what I see the Bolt doing:
1. Ask the user their ZIP code. Fetch channel metadata from a server based on that ZIP code.
2. Scan the physical channels similar to the regular TV process but ignore the encoded station and virtual channel ident information from the received signal. This results in a set of physical channels known to have non-zero signal strength.
3. Cross-reference the set of physical channels from step 2 with the metadata downloaded in step 1. The result is a denormalized table presented to the user that shows Station Ident, Virtual Channel and (important) - NOT the Physical Channel -- in my case there are many "dups" in this list in that it will show me several virtual channels that there is no way I could possibly receive (e.g. UHF stations that are 150 miles away).
4. There is a checkbox next to each channel in the table shown in step 3. The user may check and uncheck the box, presumably to signify whether the station is "real" or not.
Now, here's where this process breaks down for me:
A. It appears that although a station has been identified in the scan, and is receivable in the "antenna signal check" UI (you see a decoded stable picture), UNLESS the channel is present in the set of metadata downloaded for the user's ZIP, you will see a BLACK SCREEN if you try to view that channel in the regular TV watching Tivo mode (same if you record it). I believe I have verified this by changing the Bolt's ZIP -- this made one channel magically go from black to "working" even though nothing else had changed in the actual received signal. Note that the Black Screen syndrome is different from "can't decode the signal because it is too weak". The Tivo never displays that message (I do see that on channels it has mis-identified that don't exist at all). Rather, it seems to have a split-brain situation -- one part of the firmware knows that it can decode the signal (and it displays the picture in the antenna signal check UI), but another code path is going "ooohh no, that's not matching up with anything I know about" so the end result is black.
B. It is impossible in some cases to distinguish between pairs of displayed channels in the "channels" list UI (necessary to know which one to enable or disable). This is because adjacent channels displayed have identical Ident and virtual channel (only the physical channel differs, but that is not shown).
C. In my situation given the geography and (A), it is impossible to persuade the Bolt to display (outside of the antenna check UI) all the channels I can actually receive. This is because the set of channels known to Tivo from the ZIPs corresponding to each of the two local towns omits at least one of the channels I receive. So I get to pick between a black screen for ABC and FOX or a black screen for CBS!
I'm hoping that I'm doing something wrong, or perhaps there is a way to manually override the ZIP code thing somehow. It would also be really nice of the channel scan process paid some attention to (or even displayed) the station ident information from the received transmission. This would allow the user to declutter the large number of bogus channels mis-identified because the same physical channel happens to be used by some LP relay 200 miles away.
Thanks in advance for any light shed on this. I love the Bolt otherwise (just would be nice to get it to recognize all the network stations I can receive here).
Some background: I live in a place that has fringe OTA signal reception, however I have the antenna and preamp aspect covered (I'm a EE). On a regular TV I am able to scan for digital channels, pickup all the major networks, and view them. This isn't a question about signal strength but rather what the Tivo software does in the realm of channel scan and setup. Perhaps also significant, I live in a place where ZIP codes are very large (Montana) and also between two TV markets. So to answer the question "what set of TV channels might you be able to receive", having only the ZIP code is really not too useful.
So, first let me describe what a regular TV does in its channel scan:
1. For each physical channel in the broadcast bands, listen for an ATSC transport stream. If one is decoded, extract the virtual channel ident information.
2. Display the list of virtual channels, ident text, and (usually) physical channel for the user to review.
Here's what I see the Bolt doing:
1. Ask the user their ZIP code. Fetch channel metadata from a server based on that ZIP code.
2. Scan the physical channels similar to the regular TV process but ignore the encoded station and virtual channel ident information from the received signal. This results in a set of physical channels known to have non-zero signal strength.
3. Cross-reference the set of physical channels from step 2 with the metadata downloaded in step 1. The result is a denormalized table presented to the user that shows Station Ident, Virtual Channel and (important) - NOT the Physical Channel -- in my case there are many "dups" in this list in that it will show me several virtual channels that there is no way I could possibly receive (e.g. UHF stations that are 150 miles away).
4. There is a checkbox next to each channel in the table shown in step 3. The user may check and uncheck the box, presumably to signify whether the station is "real" or not.
Now, here's where this process breaks down for me:
A. It appears that although a station has been identified in the scan, and is receivable in the "antenna signal check" UI (you see a decoded stable picture), UNLESS the channel is present in the set of metadata downloaded for the user's ZIP, you will see a BLACK SCREEN if you try to view that channel in the regular TV watching Tivo mode (same if you record it). I believe I have verified this by changing the Bolt's ZIP -- this made one channel magically go from black to "working" even though nothing else had changed in the actual received signal. Note that the Black Screen syndrome is different from "can't decode the signal because it is too weak". The Tivo never displays that message (I do see that on channels it has mis-identified that don't exist at all). Rather, it seems to have a split-brain situation -- one part of the firmware knows that it can decode the signal (and it displays the picture in the antenna signal check UI), but another code path is going "ooohh no, that's not matching up with anything I know about" so the end result is black.
B. It is impossible in some cases to distinguish between pairs of displayed channels in the "channels" list UI (necessary to know which one to enable or disable). This is because adjacent channels displayed have identical Ident and virtual channel (only the physical channel differs, but that is not shown).
C. In my situation given the geography and (A), it is impossible to persuade the Bolt to display (outside of the antenna check UI) all the channels I can actually receive. This is because the set of channels known to Tivo from the ZIPs corresponding to each of the two local towns omits at least one of the channels I receive. So I get to pick between a black screen for ABC and FOX or a black screen for CBS!
I'm hoping that I'm doing something wrong, or perhaps there is a way to manually override the ZIP code thing somehow. It would also be really nice of the channel scan process paid some attention to (or even displayed) the station ident information from the received transmission. This would allow the user to declutter the large number of bogus channels mis-identified because the same physical channel happens to be used by some LP relay 200 miles away.
Thanks in advance for any light shed on this. I love the Bolt otherwise (just would be nice to get it to recognize all the network stations I can receive here).
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