# Significance of "Cable Signal Strength?" Troubleshooting



## maury (Jan 8, 2012)

(sorry for the length) I'm trying to help out a buddy here. He has a first gen Bolt which he thought had an audio problem (turns out it might have been the TV, but too late now...) and TiVo replaced it for a fee. Otherwise everything worked perfectly before replacement (good video, and good audio prior to a component failure).

His old cable card didn't work in the replacement Bolt. After much time on the phone with his cable carrier, with TiVo (and together), the cable company came out and spent hours trying to get it to work (cable card detected by carrier but no service). Eventually they came back and tried up to 5 cards total between the two visits. Each time they replaced a card they basically just threw the old one back in the box until they got one that "works." That is - no new in the package cable cards were tried.

He now has cable, although some of the working HD channels have issues (audio hiccups, pixelization, etc.). He doesn't get all the HD channels he is paying for (acct status was checked and nothing had changed, and some of the HD channels in his tier of service work). I don't believe he has issues with SD channels. They tested the signal from the termination point in the house to the TV and said it was fine. They replaced a bunch of older components at the termination point as a precaution. At the 5th card, the cable company says "you're on your own."

The TiVo says signal strength is around 72ish. I live about 3 miles from him, same cable company, and my Roamio says everything is 97 - 100. At least half are 100, most of the rest above 97. I tested at least 100+ channels across the entire spectrum, and the only real anomalies for me are the public access channels (all are 92-93) which makes sense to me since they probably all are on a private line to the head end provided by the carrier and all are consistent. By the way - he is all MoCA, and everything that comes into the house is over Coax. His broadband is perfectly fine.

My questions are: 
1) What is the significance of that Signal Strength number? Is it just a relative number to TiVo's input spec. requirement? That is - any signal at x db gets assigned a number depending on how optimum (or sub optimum) it is? In contrast, the cable company uses a tool to determine if the raw signal is above or below a reference signal.
2) Does a 72 on a Bolt mean the same thing on a Roamio (trying to determine if my figures are in any way relevant to him)? Different receiver designs may have different sensitivities. Does TiVo basically use the same calibration? My guess is TiVo tries to equalize the numbers between models to make remote trouble shooting simpler
3) Where is the actual RF receiver? (Not sure if this is like analog), but is there a detector stage in the card, and the RF amplification happens inside the TiVo? Or does the card detect and amplify to a level useful by the TiVo? Or does the card just look for a digital tag to validate channels according to service level, decrypt the valid ones, and pass them through? My guess is 1 or 2 since the cable guys stayed until they got a picture

Any thoughts by anyone are greatly appreciated since it's hard to get much action with all the finger pointing.


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## JoeKustra (Dec 7, 2012)

First: is this a four tuner or six tuner Bolt? Everything you have posted points to a six tuner Bolt OR a Bolt configured for an antenna.

Cable company & location? In Menu/Help/Account & System Info/System Info, is the first page correct? That Bolt is acting very "wrong".


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## maury (Jan 8, 2012)

Thanks for your quick and insightful response! I'm going to have my buddy check. I know he originally bought a first gen, 4 tuner bolt. I thought (could be wrong) it was a 400 GB drive. The replacement has 1 TB. When he told me that I just assumed sub TB drives are getting scarcer and TB drives are so cheap that it was just a silent upgrade. It's possible he has a different feature set than the original purchase. Cable co is VZ FiOS in MD. Be back when I hear back from him...


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## UCLABB (May 29, 2012)

maury said:


> (sorry for the length) I'm trying to help out a buddy here. He has a first gen Bolt which he thought had an audio problem (turns out it might have been the TV, but too late now...) and TiVo replaced it for a fee. Otherwise everything worked perfectly before replacement (good video, and good audio prior to a component failure).
> 
> His old cable card didn't work in the replacement Bolt. After much time on the phone with his cable carrier, with TiVo (and together), the cable company came out and spent hours trying to get it to work (cable card detected by carrier but no service). Eventually they came back and tried up to 5 cards total between the two visits. Each time they replaced a card they basically just threw the old one back in the box until they got one that "works." That is - no new in the package cable cards were tried.
> 
> ...


That signal strength, 72, is too low. Both my Roamio and Bolt run 97-100. Did you ever get a signal strength reading on the previous Bolt to compare to what it is on this one?

What exactly do you mean by he doesn't get all of his channels? Do they just simply not work or is there a message saying they are not authorized? The difference is if they simply don't tune in, it is probably the signal issue, if you get the message then it could be the cable card.


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## DeltaOne (Sep 29, 2013)

maury said:


> The TiVo says signal strength is around 72ish.


I had been experiencing some pixelation about six months ago. Every channel listed signal strength as 100. Which might mean 100, 105, 110, 120...who knows. Had Comcast out, they said the signal strength was fine.

I played around with different amounts of attenuation. Ended up using a -12 dB attenuator and all my signals read between 85 and 98%. Picture quality is excellent.

Also look at the dB rating (on the same diagnostics screen). The sense around here is that 35 dB is perfect, but a little lower or a little higher will work just fine. The dB rating will rise and fall with signal strength.

About two weeks ago my son's Bolt was not displaying a few channels, returning a V52 error. I've never added any attenuation on his cable run. Signal strength was generally low, ranging from about 70 to about 80. I checked the coax connectors at each end of the run. We noticed that when the Bolt was pulled out from the wall the signal strength was about 90. When we pushed it back in to the wall, its normal position, the signal strength would fall to about 70. I put a new connector on and that fixed the problem.


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## maury (Jan 8, 2012)

This is a 4 tuner unit. Took us a while to figure that out. I had to talk him through it, and have no experience with Hydra (neither does he), but he started 4 recordings and that's as far as he could go.
1) Regarding signal strength on previous unit - he has no idea (but had none of these problems)
2) By "not getting all his channels" I mean that he gets a "No Signal" message. Obviously on channels he's not supposed to get he gets a message saying he's not authorized.
3) More elaboration on signal strength - All channels with signal are 67 or higher, 72 typical, and 1 channel is at 80


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## maury (Jan 8, 2012)

DeltaOne said:


> I had been experiencing some pixelation about six months ago. Every channel listed signal strength as 100. Which might mean 100, 105, 110, 120...who knows. Had Comcast out, they said the signal strength was fine.
> 
> I played around with different amounts of attenuation. Ended up using a -12 dB attenuator and all my signals read between 85 and 98%. Picture quality is excellent.
> 
> ...


Although this sounds like a great idea, the FiOS techs replaced a bunch of connectors and the guts of the ONT. That said, the previous Bolt worked perfectly, so not really even sure what systemically has changed. It's either the card or the Bolt (or a 10% chance it's something else).


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## JoeKustra (Dec 7, 2012)

maury said:


> This is a 4 tuner unit. Took us a while to figure that out. I had to talk him through it, and have no experience with Hydra (neither does he), but he started 4 recordings and that's as far as he could go.
> 1) Regarding signal strength on previous unit - he has no idea (but had none of these problems)
> 2) By "not getting all his channels" I mean that he gets a "No Signal" message. Obviously on channels he's not supposed to get he gets a message saying he's not authorized.
> 3) More elaboration on signal strength - All channels with signal are 67 or higher, 72 typical, and 1 channel is at 80


I wish to speculate that the Bolt is confused. Here's why. A Bolt (or basic Roamio) has an AGC circuit that attempts to keep the signal level for a cable configuration at 90%. For a OTA configuration, it tries for 72%. Since AGC can only do so much it's not abnormal to see numbers outside the "perfect" numbers. Problems do happen when the signal reaches the 100% level, since the TiVo can't tell you it's at 120% and the tuner is overloaded. You sound technically skilled. The cable card has a channel list downloaded at pair time. There is a VCT ID shown in Diagnostics. It's the identifier for your headend. Note the number.

One option is to get a new unit. That would be my suggestion since it doesn't sound like you have a stable machine.

One option is to wipe the unit. That's a C&DE. You will probably have to pair the cable card again. It also is an imperfect solution. It could be a waste of time.

One option is to downgrade to TE3. That is a rollback to the previous version of your software. This works for Bolts too: How to Rollback Hydra from Roamio and Mini's v1 It may require you to pair the cable card again. It's a shame he can't put his Bolt next to yours off the same coax and use a different input on your TV/AVR. I have two Roamio and a Premiere feeding my AVR. But that would only work if you have the same headend.

Abbreviations are linked to in my signature. Good luck.


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## UCLABB (May 29, 2012)

If you are on Verizon, maybe you can take your Roamio over and see what the signal strength is. 72 is clearly too low. Either a problem in the cabling or the Bolt.

I wouldn’t bother with rolling back the UI or c&d. The issue is signal strength or the Bolt tuner circuit.


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## XIBM (Mar 9, 2013)

Make sure the coax connectors are tight. What kind of splitters are in the network?


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## maury (Jan 8, 2012)

Guys - thanks so much for all of the insightful responses. What a great community! Joe (thanks for the abbreviations) & UCLABB: Basically, I learned what I came hear to find out. That is, if it's truly a signal strength issue, the Bolt appears to be more responsible for that than the cable card. What partially threw me was his description of the disposition of the cards. First was the original (previously) working card, then shipped a replacement card, then the FiOS guys came out and couldn't get 2nd card to work. Came back next day with a bunch of cards loose in box on the truck. If it didn't work, it just went back in the same box. That's when they replaced some ONT components (he couldn't tell me what exactly). At that point we had progress - weak signals.

So, considering he doesn't like Hydra, he's considering rolling it back anyway, but I think I'll tell him to hold off because if the rollback fails, they'll blame that as the issue. As for XIBM's coax idea, it's worth a (long)shot. No idea about the splitters, but like I said, it all worked perfectly before the faux issue on the original Bolt. I'm thinking it's the new Bolt. I'm going to ask him to bring it over, or I'll bring my Roamio over, and see if that works. I'll check the head end VCT ID first. Thanks again to everyone in this thread for helping to narrow this down. To be continued...


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## JoeKustra (Dec 7, 2012)

maury said:


> So, considering he doesn't like Hydra, he's considering rolling it back anyway, but I think I'll tell him to hold off because if the rollback fails, they'll blame that as the issue. As for XIBM's coax idea, it's worth a (long)shot. No idea about the splitters, but like I said, it all worked perfectly before the faux issue on the original Bolt. I'm thinking it's the new Bolt. I'm going to ask him to bring it over, or I'll bring my Roamio over, and see if that works. I'll check the head end VCT ID first. Thanks again to everyone in this thread for helping to narrow this down. To be continued...


Sounds like a plan. The Virtual Channel Table is just a number assigned to the QAM to whole number list used by your headend. Worst that could happen is missing or wrong channels.


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## maury (Jan 8, 2012)

Liftoff! Thanks to everyone for the help. I brought my TiVo over last night (family wasn't too pleased since nothing worked until I brought it home! ). My signals there were more or less the same as what they were at home. We called TiVo support and it took some convincing, but they finally started believing some of their own diagnostics and declared a "DOA," so he has a replacement on the way. 

The early complication was that there were definitely some cable card issues (FiOS guys couldn't get the first few cards to register). Part of it was not being able to tell which cards in the box were good ones, partly an ONT issue, and so on. But once VZ left and said it's the TiVo, we still had our doubts. That was why I originally asked which was more of a factor in signal strength - the TiVo or the card? It was an education watching some very weird behavior on some channels - SNR's flipping between 9-15-21, back to 9, etc. Also db signal levels much lower on some channels, watching some channels that I had 98 - 100 on getting no lock, and flipping between QAM 256 and QAM 64 (I guess that was the tuner scanning for a signal - not really sure how this works). So, we finally proved it to TiVo's satisfaction. Your help gave me the confidence that we were on the right track. That was important because TiVo kept pushing back, insisting lower channels don't need as much signal (67 is fine), and suggesting my TiVo probably is authorized on the higher channels where he's he's not getting signal.


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## EmmaFrost (Sep 24, 2010)

maury said:


> Liftoff! Thanks to everyone for the help. I brought my TiVo over last night (family wasn't too pleased since nothing worked until I brought it home! ). My signals there were more or less the same as what they were at home. We called TiVo support and it took some convincing, but they finally started believing some of their own diagnostics and declared a "DOA," so he has a replacement on the way.
> 
> The early complication was that there were definitely some cable card issues (FiOS guys couldn't get the first few cards to register). Part of it was not being able to tell which cards in the box were good ones, partly an ONT issue, and so on. But once VZ left and said it's the TiVo, we still had our doubts. That was why I originally asked which was more of a factor in signal strength - the TiVo or the card? It was an education watching some very weird behavior on some channels - SNR's flipping between 9-15-21, back to 9, etc. Also db signal levels much lower on some channels, watching some channels that I had 98 - 100 on getting no lock, and flipping between QAM 256 and QAM 64 (I guess that was the tuner scanning for a signal - not really sure how this works). So, we finally proved it to TiVo's satisfaction. Your help gave me the confidence that we were on the right track. That was important because TiVo kept pushing back, insisting lower channels don't need as much signal (67 is fine), and suggesting my TiVo probably is authorized on the higher channels where he's he's not getting signal.


Hi, I'm getting the exact same issue you described above, right down to the flipping SNR and QAM. I'm on my 1st TiVo Bolt replacement box, was the switching due to cable card issues or the TiVo itself?


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## maury (Jan 8, 2012)

Emma - it was definitely the TiVo itself. It just could not capture signals strong enough across the authorized channel list to be usable. Some of the borderline channels would be Ok for a minute or two and then start breaking up. Other SD channels, and a rare HD channel might work adequately at the higher ranges of decidedly reduced signal levels, but then many channels did not function at all. No signal type messages, etc. My TiVo on the same connection pinned the meter on every channel. It took some convincing to get TiVo to accept this (especially since this was a replacement TiVo).


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## pl1 (Jan 18, 2007)

maury said:


> Emma - it was definitely the TiVo itself. It just could not capture signals strong enough across the authorized channel list to be usable. Some of the borderline channels would be Ok for a minute or two and then start breaking up. Other SD channels, and a rare HD channel might work adequately at the higher ranges of decidedly reduced signal levels, but then many channels did not function at all. No signal type messages, etc. My TiVo on the same connection pinned the meter on every channel. It took some convincing to get TiVo to accept this (especially since this was a replacement TiVo).


I would just like to chime in here. I took advantage of the recent 4 tuner refurb Bolt sale a couple of days ago. Cutting to the chase, I am having the EXACT same problems. The way I am able to tell right away that it is the Bolt is that I took the cableCARD out of my Roamio, and successfully paired it on-line with Comcast to my Bolt.

I had access to all of the lower tier channels, but none of the news or sports upper tier channels. What clued me in to the signal strength problem is that I COULD access the music channels at 480i resolution, but it was all pixelated. That REQUIRES authorization, but the signal strength was 67. And for all of the channels I could NOT get, it showed V52.

I was able to get a very knowledgeable Woman at Comcast (if you can believe it! And on a Saturday!). She knew all about the procedures to check with the TiVo Bolt. At one point she wanted to do a guided setup. I told her I had just finished doing a clear and delete. So, the troubleshooting left us with removing the coax splitter to my modem and hooking up straight to the wall. And if that did not work, she would send out a tech.

It was at THAT point I told her there was no sense going any further since I knew my Roamio works fine on the exact same connection. I asked her to remove the pairing for the Bolt, and I was able to go back to pairing my Roamio on-line, successfully. Immediately I had all of my channels back.

Needless to say, I am returning the refurb, which is probably why it is a refurb.


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## JoeKustra (Dec 7, 2012)

pl1 said:


> Needless to say, I am returning the refurb, which is probably why it is a refurb.


Tools used for a refurb: Windex and paper towels.


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## pl1 (Jan 18, 2007)

JoeKustra said:


> Tools used for a refurb: Windex and paper towels.


True That. I'm sure if it powers up, it's good to go!

EDIT: Clarity


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