QAM mappings keep getting lost

[LaoChe]

My channels are all in clearQAM tuned through 2 Silicon Dust HDHRs and I am having a lot of trouble mapping them in SageTV. When I last mapped all of the channels (a few years ago) I thought that I had done it in the HDHR software but I know I didn't have this problem then.

If I do a channel scan I get something less than all of the channels (anywhere from 50% to 90%). I spend a couple or hours mapping them all from something like '55-0-549' to '549 AMC'. If I do another scan to find those missing channels I usually get them but all of my old mappings are no longer valid. 55-0-549 can no longer be tuned but now there is a new channel maybe something like 112-0-549 that maps to 549 AMC which means remapping every channel over and over. I think there is something I need to do differently but I really have no idea what it is.

Very much related I think is that I get some duplicates (i.e. 92-0-60 and 48-0-60 are both HGTV so I map 1 and disable the other)

Also a separate question - what do you do when the guide information is incorrect - for example my cable provider has channel 27 YDN which is in the guide and also 527 YDNHD which is not in the guide. Is there any way to map that channel so it has guide information? It has the same programming as 27 YDN so I tried mapping it to 27 but then I can't remap 27. There are only 3 channels like this so it's not a big deal - just wondering.

I think all of this boils down to my lack of understanding of how to map these channels.

Thank you.

[Monedeath]

Originally Posted by LaoChe

If I do a channel scan I get something less than all of the channels (anywhere from 50% to 90%). I spend a couple or hours mapping them all from something like '55-0-549' to '549 AMC'. If I do another scan to find those missing channels I usually get them but all of my old mappings are no longer valid. 55-0-549 can no longer be tuned but now there is a new channel maybe something like 112-0-549 that maps to 549 AMC which means remapping every channel over and over. I think there is something I need to do differently but I really have no idea what it is.

That "problem" isn't a SageTV "Issue" strictly speaking. SageTV was told to look for "Virtual" channel 549 on physical channel 55, sub-channel 0, on the VHF/UHF radio spectrum allocated for Television(or whatever it is being called for HD these days). Since the Cable Company moved it to the physical channel(frequency band) of channel 112, SageTV is failing to tune in the channel because it is still looking for it at the old location.

CableCard tuners automatically update when they switch channels around like that, I believe there was an effort by EnterNoEscape or someone else to change how SageTV reads QAM channel mappings(so that it would look at the "minor" channel number--that third set of numbers), but don't know what happened with that change, probably would still require an update scan at the least to figure out where the channel went. CableOne in my area constantly switching a couple of the QAM channels around in regards to their "physical location" on the dial ultimately had me pulling my QAM Tuners off of the Cable outlet and plugging them into an OTA Antenna instead, only the CableCards remain connected to them at this point.

EnterNoEscape does have the OpenDCT tuner software as something that I think might be able to help with this if you let it handle the HDHomeRun tuners, but someone who uses OpenDCT or ENE would need to confirm or deny.

Very much related I think is that I get some duplicates (i.e. 92-0-60 and 48-0-60 are both HGTV so I map 1 and disable the other)

I know that for CableOne just before they did their transition to full digital, there were both HD and SD versions of some channels available through ClearQAM. So that could be some of what you were seeing, or they were getting ready to transition that channel from one location to the other, or were using it for testing, or something else more obscure.

Also a separate question - what do you do when the guide information is incorrect - for example my cable provider has channel 27 YDN which is in the guide and also 527 YDNHD which is not in the guide. Is there any way to map that channel so it has guide information? It has the same programming as 27 YDN so I tried mapping it to 27 but then I can't remap 27. There are only 3 channels like this so it's not a big deal - just wondering.

What I typically did, as I was biased in favor of HD was I remapped the HD channel to the logical channel number for the SD Channel as it had guide data(the only thing that would be incorrect is the HD Flag, which isn't always correct on the HD channels anyhow). I'd then disable the SD version. But your mileage may vary.

[Fuzzy]

With ClearQAM, you are going to always be at the mercy of the cabeco. With their own equipment, and even cabelcards, they are able to move channels all over the place, daily if they choose, and it doesn't affect operation at all. ClearQAM will be messed up by this every time. You really might want to look at CableCard, and see if it's an option for you, because it really is the best way to keep your channelmap up to date - but you'd need to find out what their DRM scheme is (sometimes this can be determined in the service menu of a cablebox).

[EnterNoEscape]

You need to have at least one CableCARD tuner available, but OpenDCT is able to read the mappings from the CableCARD tuner and use them to tune in a channel on a ClearQAM device. From SageTV's perspective it's completely transparent since OpenDCT handles all of the remappings.

However, if your cable company moves the mappings around a lot, I would go with Fuzzy's suggestion to just get a CableCARD tuner.

[LaoChe]

I don't know if anybody can answer this question without knowing the specifics of my cable provider but I am curious if there is anything else that would cause this that I can look into (I am looking into OpenDCT too). I have had channels change in the past but only when the cableco is realigning things or adding new channels. In fact, I still have my old Windows SageTV server up and running and in use every day until the new one is working and it has been working fine with no remappings for at least 2 years.

But with the new server I just set up (V9 on ubuntu) it almost seems to me like it is a tuner sensitivity issue because my channel mappings seem to work just fine if I record something but it's when I do a channel scan that they all get lost. I keep doing update channel scans because I have never been able to get a complete lineup. Sometimes l scan and get 75 channels, sometimes it is 150 channels but there are always always a handful of standard channels that I definitely should have that are missing (although which ones are missing changes each time). Oddly enough there are only about 10 channels we usually watch but no matter what I have never done a scan and managed to get all 10 at once.

The strange thing is, if I run a channel scan, remap everything and then run an update scan 5 minutes later, all of the original channels are already no longer tuneable. It's almost as if the cableco is either randomizing the channels or they are broadcasting on multiple channels and each time Sage is just picking up 1 (or none).

Sometimes I have every single regular and premium channel (including HBO, Starz, etc.) but sometimes I just get a half of the most basic channels (weather, cnn, etc.) - but always the old mappings are not tuneable.

If it helps my cable is provided by our municipal electric company and everything seems to be broadcast unencrypted.

I know that's a hard question to answer but any guidance that might at least point me in the right direction would be a help. I really am at a loss as to why it is so unpredictable.

Thanks again.

[KeithAbbott]

Originally Posted by LaoChe

The strange thing is, if I run a channel scan, remap everything and then run an update scan 5 minutes later, all of the original channels are already no longer tuneable. It's almost as if the cableco is either randomizing the channels or they are broadcasting on multiple channels and each time Sage is just picking up 1 (or none).

What you are describing sounds like switched digital video.

[Monedeath]

Originally Posted by LaoChe

The strange thing is, if I run a channel scan, remap everything and then run an update scan 5 minutes later, all of the original channels are already no longer tuneable. It's almost as if the cableco is either randomizing the channels or they are broadcasting on multiple channels and each time Sage is just picking up 1 (or none).

Sounds like Switched Digital Video(SDV), haven't encountered it myself, but based on its theory of operation, it should be doing exactly what you describe.

Basically they have a SDV box/device in your home telling them what channels you're watching at a given time, and you possibly share a "common link" with a number of others in the neighborhood. So long as the SDV system detects that "someone"(or something) is "watching" a given channel, that particular channel will retain the current mapping("physical location" in the frequency bandspace).

However, the moment it detects that channel is no longer in use, it can reassign that "location" to something else. As the CableCo Provided equipment is built to work within that system, and the matter that they're using an abstraction of channel numbers(what I called "virtual" previously) rather than the old Analogue method of actual giving it a specific channel, they can do this on the fly and their devices will simply do its version of a DNS lookup(not likely to be anything close to the same protocol involved) to determine where channel 456 happens to be at a particular moment in time once someone asks for it, and if it isn't presently available, to please make it available.

This allows them to offer up hundreds of channels worth of content, but only have to use, for example, 25 channels worth of bandwidth for any set of households. As most people are likely watching locals, weather, news, or sports. Which will take up the first 10 or so channels, the other 15 is for the other content people may go for(the other 100+ channels) at a given time of day.

Edit to add: This is how many CableCo's are offering ever increasing speeds for Cable Internet, they still are pushing Fiber ever closer to the household, but the less content they're "pushing" needlessly into the end-users home, means that much more bandspace they can then dedicate to data services instead, either giving you faster internet, or giving them more customers using the same "loop" as the case may be.

[Fuzzy]

Yeah, definitely SDV - it's just odd that they are using SDV, but not using encryption. Certainly not out of the capablities of their system, just a choice they'v made at the head-end. If they aren't using encryption on the channels you are looking watching, then they likely also aren't very aggressive on the DRM flagging either, so CableCard may work well for you. An HDHR-Prime, along with a CableCard and Tuning Adapter from the cable company, and OpenDCT, should work well for you.

[LaoChe]

Now I believe that this is a problem with tuning in SageTV. After a couple of weeks of back and forth with the cable company I have confirmed that they are not using switched video. They did offer me a cable card but now I am thinking I don't need it after all. In fact, after a lot of discussions they sent me their channel mapping list. 90% of their channels have 1 static physical channel assigned to 1 logical channel (they do have a few that are broadcast on a couple of different physical channels at the same time - this is why it seemed like stations were showing up on different physical channels before. But I was wrong about that). I installed OpenDT and it seems to be running but that didn't seem to make a difference with this problem. Using the cable company's list I focused on 1 channel that should be coming through clean and here is what I found:

Channel is 111-0-559 AMCHD.
Just to be sure I start by clearing all previous mappings, removing all tuners and adding just one of them back.
Complete a channel scan - 49 found (out of about 147 that should be there)
111-0-559 shows up - I remap the logical channel to AMCHD (559) from the available channels
Go to TV guide and there is data for 559 AMCHD, tune into a show it works fine.
Do a second channel scan and another 50 channels show up. However, 559 AMCHD can no longer be tuned. 111-0-559 does not show up in the list either.
Clear mappings from 559 - now 559 does not show up and 111-0-559 does not show up either
Do a 3rd channel scan and 111-0-559 shows back up and tunes just fine.

This same thing happens if I just leave the system alone for a few hours, I gradually start losing channels but if I clear the mappings and rescan I can get them again.

I bought a RF amplifier as well thinking maybe the signal wasn't strong enough but that didn't make a difference.

Any ideas?

Thanks!

[EnterNoEscape]

OpenDCT requires that at least one of your tuners has a CableCARD to automate QAM channel mappings, so I'm not surprised that it didn't help.

[LaoChe]

OK. Thanks. That was just a shot in the dark anyway. I can still get a cablecard from my provider if I need one but it seemed like I shouldn't need one in this situation. I think. Maybe?

[Fuzzy]

Originally Posted by LaoChe

OK. Thanks. That was just a shot in the dark anyway. I can still get a cablecard from my provider if I need one but it seemed like I shouldn't need one in this situation. I think. Maybe?

CableCard is the ONLY way to get notified by the Cable Company automatically when lineups change - and certainly the only way to make SDV requests (Cable boxes have cablecards inside as well). It seems like if they are still broadcasting unencrypted streams, it is unlikely they are using very restrictive DRM tagging.

[JustFred]

Originally Posted by LaoChe

Now I believe that this is a problem with tuning in SageTV. ...

Any ideas?

Your original post stated that your cable channels are Clear QAM. Do you have a TV that's connected to the cable? If so, have you tried running a channel scan on the TV? Does the TV find all the channels that you're expecting? Don't worry about channel mapping at this point. Run multiple scans on the TV to confirm that your results are consistent. This will give you some confidence that the cable system isn't sending bogus lineup info, nor using SDV.

If the TV's scan is good, then run a scan using the HDHR software, but do NOT remap any channels yet. Follow this by running a second scan using the HDHR s/w. Do both HDHR scans give consistent results? Are they the results you're expecting? Do these results match the TV's channel scan?

Only after you've gotten to the point where you're getting consistent scans (on the TV and HDHR s/w) would I attempt to do any remapping.

Others may disagree, but, for Clear QAM, I've found it advantageous to do any remapping in Sage, NOT in the HDHR software. There are several reasons for this, but one big advantage is the fact that (internally) Sage keeps track of "before" and "after" channel info, which greatly eases subsequent scans/remaps when the CableCo changes their channel lineup.

If I recall correctly, the correct sequence is: 1) channel scan using HDHR s/w. 2) channel scan in Sage (repeat for every HDHR input source), then 3) remap in Sage. If you're using the same lineup for each tuner, I remember it was only necessary to remap on one of the tuners, but I may be wrong about this.

[LaoChe]

JustFred, thanks for the advice. That was a great idea. It's been so long since I had the cable hooked up directly to the TV I had forgotten about that. I did as you suggested and here are my results:

TV scan - 23 analog and 183 digital channels found - I tuned into at least 30 of them and all seemed to work fine on two different days.

HDHR scan - 184 digital channels found on 2 different days - tuned into 12 of them picked at random and all worked fine.

SageTV -
scan 1: 51 channels found (including 1-16 which don't actually work) the other 35 are valid
scan 2: done without remapping anything just did an update channel scan immediately after scan 1 - 41 new channels found 12 of the scan1 channels are no longer tuneable
scan 2: done without remapping anything just did an update channel scan immediately after scan 2 - 19 new channels found 29 no longer tuneable

So now it seems that the problem is with SageTV tuning itself and the remapping has nothing to do with it. I have attached a text file showing actual channels added and deleted in each scan. The only pattern there seems to be is that both seem to occur by major channel - for example scan 1 found nothing on channel 46 but scan 2 found 11 channels on 46. Scan2 lost all 5 channels found on 112 during scan1.

This might have nothing to do with it but I notice that on the TV it takes about 3 seconds to tune a channel. Is it possible that SageTV just needs to give it more time when doing a scan? Is that something that can be adjusted?

Thanks a lot!

[Fuzzy]

Out of curiosity, have you tried using opendct to connect sage to the hdhr, and then scan from in sage? OpenDCT does its scan a little different, and gives more log info, so it might be easier to figure out.

[Tiki]

Are you using Sage V7 or V9?
I'm pretty sure there were some posts a few months ago by someone who had made some fixes related to clear qam tuning in V9. I didn't pay real close attention at the time since most cable providers have eliminated clear qam support anyway. But, if you are using Sage7 you could try upgrading to v9 and see if it helps.

[LaoChe]

This is a brand new install using V9 on an Ubuntu server

[JustFred]

Originally Posted by Tiki

Are you using Sage V7 or V9?
I'm pretty sure there were some posts a few months ago by someone who had made some fixes related to clear qam tuning in V9.

I made those fixes. But they only affect internal tuners such as the HVR-2250; no impact to the HDHR.

So now it seems that the problem is with SageTV tuning itself

Your results indicate good RF signal strength and quality into the HDHR, so there's probably no need to fiddle with amps or anything else ahead of the tuner.

Background: when the HDHR does a channel scan, it stores this info. Then when Sage does a scan, the HDHR re-creates and returns a transport stream using it's stored info. That's why Sage's scan takes only a couple of seconds.

It appears the issue is related to the scan info that HDHR delivers to Sage. For whatever it's worth, I'm still using f/w ver 20130328 on my HDHR3-US boxes and have no issues with clear QAM. Exactly which HDHR hardware are you using? What version of firmware is installed?

[LaoChe]

The tuner I am working with right now is a HDHR-US with firmware version 20150406. I also have a HDHR4-2US with firmware version 20150826. Both seem to get the same results in the HDHR scan and the SageTV scan.

Also, I am not able to edit channels at all on either model (I used to be able to but that seems to have been disabled in later firmware versions). The scan returns a list of channels in a raw format (i.e. CH28-504) but the guide number and guide name are blank and can not be edited. When the SageTV scan runs it is not quick, it can take a half hour each time.

Should I think about downgrading the firmware so I can edit the channels in the HDHR software?

Thank you.

[JustFred]

I'm surprised the guide name/number info isn't displayed in the HDHR setup software, and that Sage takes so long to scan. But my experience is under Windows; could be that the Linux environment behaves differently. Maybe someone else will chime in here.

My preference is to not edit any of the channel info within the HDHR s/w; Sage seems to do a better job with that. But it might be a good idea to update to the latest s/w, drivers & f/w. Be aware that once you update, you probably can't downgrade. That's a limitation imposed by CableLabs.