Loss of signal strength, but only on three channels

First, do a channel scan on the TiVo to re-verify existing channels - sometimes this alone can fix a problem like this.

Second, see if the TV that is working can show diagnostics information about the received channel - specifically, you need to verify the transmit frequency or channel number (not the display channel number).

Now check the TiVo channel list to verify that the correct channel (verify BOTH the display channel number and transmit channel number) is available and checked. Also verify no other channel with the same number is checked.

If you still cannot tune in the questionable stations, see if they display anything in the Antenna Signal Strength screen (which may or may not be working at all, depending on the software version currently running on that box).

 

Disclaimer...I'm not familiar with MOCA technology.

Be sure nothing has changed regarding the channel repack. Call the stations that you're having problems with and ask them if anything has changed...antenna redirected, transmitters moved to new tower/location, power reduced, etc.,.

Verify that the spare bedroom television is still receiving with a 72 signal strength measurement. If indeed it has a signal strength of 72 then that tells me nothing is wrong with the physical antenna, don't mess with it. Something between the antenna and the main television is robbing signal strength. There is apparently good signal strength at the antenna feedpoint.

Beyond the stations having done something that is affecting things I would start by completely removing anything that could steal signal strength from the main television. Remove the splitter, surge suppressor, and MOCA filter, *and* TIVO Bolt (if you have a tuner in the main television). Make a "home run" connection between the antenna and main television. If the main television picks up the missing channels then start adding things back to the feed while monitoring signal strength...start by adding back in the Bolt. If reception is good with the Bolt then nothing to change/adjust/reset with it. Move on to the next piece of equipment. Etc.,.

*Is the spare bedroom television on a shorter cable run than the main television? Longer coax cables can impact reception.
*Is the surge suppressor protecting both televisions? Surge suppressors can go bad.

Maybe try swapping the coax lines coming out of the splitter to see if that affects anything. Splitters seem like they shouldn't fail, but stranger things have happened...there might be a bad output port.

Just some thoughts.

 

Two more things...

Are there any new structures nearby that could actually be interfering with reception?

How long has this system been in place? Years? Several months?

 

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Recently I had problems with just one channel. It was on real channel 10. My TV did not have any issues with the channel, just the TiVo. Turned out to be LTE interference. A LTE filter solved it for me. I was not aware of any new cell towers anywhere near me.

 

Is there a pre-amp installed at the antenna?
How long of a coax run is it between the Tivo and antenna?
What model/brand antenna is installed?
What are the call signs of channel 8 an 17?

Sure, the television might possibly have a more sensitive receiver. But, I'm not sure whether the Tivo could suddenly stop receiving on only certain channels. Seems like a problem would affect all channels, but I'm no expert.

Some thoughts....

It could be that the problem channels have suddenly moved from the UHF region down to a VHF frequency and the antenna has become less effective at those frequencies (the other channels possibly still in the UHF region).

It could be that the channels have suddenly increased their power and it's overloading the Tivo. The receiver on the television could be opposite from being more sensitive...it could be less sensitive and thus able to handle the stronger signal. Maybe even add a splitter between the coax and Tivo to create some "loss".

 

Something else...have you *called* the stations and asked to speak to an engineer? They usually are glad to talk with folks to work problems out. You can find out if anything "changed" about the time the problem started.

 

I think I would call the station. 17 looks like it’s a repeater of the same channels on 8 (PBS). Both of those going out rules out an antenna issue, as 8 is a Hi-VHF station, and 17 is a low power UHF fill in for the metro area in Wichita. KAKe, the ABC affilliate broadcasts in a similar fashion, with Channel 10 and real channel 21 as the fill in. Both will display as 10.x. If they can get either of those two, I really doubt that this is a Tivo tuner or antenna problem. LTE signals are nowhere near VHF (edited from UHF) banwidths, so you can rule that out.

Only other possibility is that the tivo channel selected in the Tivo channels setting is the lower power UHF signal, and not the VHF (or vice versa). If the locked frequency was trimmed back for maintenance, it might result in the lower signal strength and SNR.

 

Nearly any TV tuner will typically be more sensitive than the tuner array in the Bolt. Its not that the Bolt signal is “split”, as there is no additional insertion loss inside of the Bolt beyond the normal 6 to 8 dB loss associated with any tuning set. The signal to noise ratios are more a function of the Bolts internal circuitry. And I wouldn’t put too much stock in the reported SNR on the diagnostics page: if you pay attention to it, you will notice it moves directly in lockstep and dependent with changes in signal strength. As the Bolt’s AGC limits signal power readout to that magical 72, the SNR reported should be fixed at various levels while the gain is applied or reduced, not after the fact. It’s derived by assumption, not measured.

Thanks for the info on the other channels going. Thats the first complete detail you posted here, other than “channel 8” in Kansas. With that added info, yep, quite possible the Bolt tuner has gone bad.

The best of luck to you.

 

Yet it was a LTE filter that drastically improved my channel 10 reception. My CH10 reception disappeared overnight. No new towers in my area and I am at least 3 miles from a cell antenna. My Roamio continued to receive CH10 fine, just my BOLT lost CH10.
You can always get one from a place that allows returns to try it out.

 

I read your post over in the Coffee House and understand your frustration. If the Bolt is still under warranty, I wouldn't get overly complicated explaining the problem to the CRs. I don't know how detailed your present trouble ticket is based on your conversations with TiVo.

I've been through this before with TiVo and replaced two broken Bolts. One under warranty and one outside warranty which TiVo replaced for $50.00. I kept it simple. We're not expected to be trained technicians, diagnosticians, and I simply told them I did the basics: check all the wires, reboot, plug/unplug. Imagine you are one of your parents calling TiVo support. I would simply state the Bolt fails to now receive OTA channels when it worked fine last week. Yes, I have done the diagnostics my limited technical abilities allow and it still doesn't receive TV channels which work fine on a TV without the Bolt connected. It is clearly broken and I want it replaced. Stick to your script. Be respectful but firm. Tell them you are not satisfied if they tell you they won't do anything to assist. They will escalate the issue when pressed.

 

While I am no expert on Tivo, but each tuner in a Tivo will require a split. If you have two OTA tuners, that would be a 3DB loss compared to running the coax directly into the TV. If it has 4 tuners, it would be 6 db. Attic mounted antennas typically lose up to 10db going through the roof (up to 20db if the roof is metal or wet). I would highly recommend moving the antenna outside, which would probably solve all your parents problems. If that is not possible, try adding a medium gain, low noise amplifier at the antenna. As a test, bypass the 2GHz splitter. Connect the line to the Tivo directly to the Moca filter. That will add 3db to the Tivo's signal strength. If that fixes the problem, then you will need a distribution amplifier instead of the splitter.

 

DaveInlr_, a preamp isn't a bad idea. I know that in my rural setup that if I didn't have my Juice preamp I wouldn't have very good OTA reception. I've got probably a 70' coax run from antenna to Tivo with a splitter in the line. It's just the area that I'm in with lots of forest between us and the towers some of the signals at the antenna are just too weak to make the cable run without being amplified.

I did a "shoot out" with the (then) new Channel Master Amplify and the AD Juice. Without a doubt the AD Juice worked best for me in my location...it's low noise I think really helped with my weak signals.