# Help Understanding Tivo OTA/ATSC Channel Config?



## dboreham (Jan 20, 2016)

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).


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## JoeKustra (Dec 7, 2012)

You have joined the group of people who don't live in a major metro area. As you found, your zipcode (DMA) defines your channel list. I do wonder if something changed since if I do a channel scan and new channels are found, at the end I'm prompted to add or reject those channels. I don't have a Bolt.

You have learned: TiVo doesn't care about PSIP. I hope someone with better experience will jump in and help. Also, there is a lineup form if you feel the errors should be fixed: https://www.tivo.com/lineup.html


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## dboreham (Jan 20, 2016)

JoeKustra said:


> You have joined the group of people who don't live in a major metro area. As you found, your zipcode (DMA) defines your channel list. I do wonder if something changed since if I do a channel scan and new channels are found, at the end I'm prompted to add or reject those channels. I don't have a Bolt.
> 
> You have learned: TiVo doesn't care about PSIP. I hope someone with better experience will jump in and help. Also, there is a lineup form if you feel the errors should be fixed: https://www.tivo.com/lineup.html


Most helpful thanks. I wonder, is there a way to examine the "lineup" data for a given ZIP? That way could easily say whether the channels I can receive are present or not for my ZIP.


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## JoeKustra (Dec 7, 2012)

dboreham said:


> Most helpful thanks. I wonder, is there a way to examine the "lineup" data for a given ZIP? That way could easily say whether the channels I can receive are present or not for my ZIP.


fur sure. Use www.zap2it.com and enter your zipcode. Select OTA and you will (as of now) see the same database as TiVo should be using. There is a question about that since Rovi bought TiVo and may not be using Gracenote soon. That will be interesting/a disaster.


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## 9300170 (Feb 21, 2003)

I dont see what the problem is. Just submit a channel update request to TiVo and theyll add the channels to your zip code. I've done it before. It takes a couple of weeks and your good to go. Theyll even create custom mappings for small cable installs like apartment buildings, etc. youre paying for the service, use it.


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## dboreham (Jan 20, 2016)

9300170 said:


> I dont see what the problem is. Just submit a channel update request to TiVo and theyll add the channels to your zip code. I've done it before. It takes a couple of weeks and your good to go. Theyll even create custom mappings for small cable installs like apartment buildings, etc. youre paying for the service, use it.


I think what you don't get is that the way Tivo handles channel configuration is highly counter intuitive and confusing. Once I realized how it works I think you are right. You can identify any channel that receivable but not in the lineup (this is not easy to do, but possible if you use another TV to properly ID the channel) and have it added.

One improvement they could easily add to the UI would be to display "this isn't the channel you are looking for" rather than a black screen. Even better : that plus "go read http://www.tivo.com/<page that explains their insane channel selection process>"


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## dboreham (Jan 20, 2016)

JoeKustra said:


> fur sure. Use www.zap2it.com and enter your zipcode. Select OTA and you will (as of now) see the same database as TiVo should be using. There is a question about that since Rovi bought TiVo and may not be using Gracenote soon. That will be interesting/a disaster.


Ah ha. Yes, same set of channels as my Bolt has. Thanks.


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## JoeKustra (Dec 7, 2012)

dboreham said:


> Ah ha. Yes, same set of channels as my Bolt has. Thanks.


When it comes to "new", "live", and out of country programs, zap2it is more accurate. Trust but verify.


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## dboreham (Jan 20, 2016)

I found one specific case where zip2it (and also Tivo) is wrong for my location:

The station KWYB-LD is listed as having virtual channels 28.1 and 28.2 whereas in fact it has 18.1, 18.2 and 18.3. In this case my Bolt will decode and display the channels, but only if I check the box for the 18.x copy of the channels in the list. It does not however have any guide information because the guide thinks these channels are 28.1 and 28.2 (and no .3). If I enable those copies of the channels in the list, I get the black screen.


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## JoeKustra (Dec 7, 2012)

TiVo doesn't do well on translator stations, so you may need to tell them. More information:
https://en.wikipedia.org/wiki/KWYB


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## dboreham (Jan 20, 2016)

JoeKustra said:


> TiVo doesn't do well on translator stations, so you may need to tell them. More information:
> https://en.wikipedia.org/wiki/KWYB


Yes, I filed two lineup tickets. One for 18.x KWYB (which I suspect is a case where the translator is re-broadcasting the main station transport stream without changing the virtual channel/ident to 28.x and xxx-LD) and also for the second stream broadcast with KULR (KULR-SWX).


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## dboreham (Jan 20, 2016)

fwiw the 18.[1,2,3] stations are present in the Butte lineup on zap2it so hopefully it will be simple to make them show up for my ZIP:

http://tvschedule.zap2it.com/tvlistings/ZCSGrid.do?stnNum=62998&channel=18.1&aid=tvschedule
http://tvschedule.zap2it.com/tvlistings/ZCSGrid.do?stnNum=64585&channel=18.2&aid=tvschedule
http://tvschedule.zap2it.com/tvlistings/ZCSGrid.do?stnNum=100084&channel=18.3&aid=tvschedule

The station identifiers are different vs the listings though: KWYB-ABC, KWYB-FOX and KWYB-SWX.


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## dboreham (Jan 20, 2016)

And the missing KULR-SWX is present in the Billings listings:

http://tvschedule.zap2it.com/tvlistings/ZCSGrid.do?stnNum=61545&channel=8.2&aid=tvschedule


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## JoeKustra (Dec 7, 2012)

I feel for you. I wish I had OTA myself. I haven't had OTA since 1980. My present map: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=e2cb387626992c

Maybe with a 500' tower.


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## dboreham (Jan 20, 2016)

JoeKustra said:


> I feel for you. I wish I had OTA myself. I haven't had OTA since 1980. My present map: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=e2cb387626992c
> 
> Maybe with a 500' tower.


Interesting. I hadn't tried that site in a while. Unfortunately for me it a) uses the FCC database of transmitters which is once in a while inconsistent with reality and b) its terrain model is not accurate enough for here (it says I can receive a UHF station that transmits from only 2 miles away, but there's millions of tons of rock between me and it!).

Back in analog-days, we had no usable OTA signals -- the two VHF stations around here were so close that we had terrible ghosting and none of the UHF stations were within line-of-sight. It was only when my kids turned on a TV in a camper we had parked in the driveway a couple of years ago that I realized we could now receive the VHF stations perfectly fine with a simple dipole. DTV had dealt with the multipath. So I began the process of trying to receive some UHF stations. It took a 16dB antenna mounted up on the highest building we have but it worked. Nobody around here believes you can receive OTA signals but it is possible.


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