Peculiar Channel Tuning Problem

Firstly, I own the Tablo Quad.

For the last 3-4 months I have been unable to receive one channel in my area. I kept getting a weak signal error. I assumed that the station was flakey, because occasionally it would come back and I’d be able to watch it again. However, for the last 3 weeks or so I haven’t been able to tune this channel but one day.

Today, I finally had time to take a closer look at this problem. I checked to see if the channel was presently being tuned on the Tablo. It was not, and I received the weak signal error. I have two TVs with tuners. I hooked them both up one at a time to the antenna, and received the channel without any problem. The signal was strong on both sets. I disconnected the antenna cable from the second tv and plugged it back into the Tablo. Again, I got the weak signal error. I tried a channel rescan, channel found, same result (weak signal). I tried changing my location (mostly for the heck of it), and did a another channel rescan, channel found, weak signal error. I than proceeded to check both TVs again, and voila, channel received on both. Connected the antenna back up to Tablo, and got the weak signal error. For clarification, I did change my location back to where I am actually located and did another channel rescan. I rescanned, channel found, weak signal error.

When I was able to receive the channel on two TV sets, but not the Tablo I began to look at the Tablo more closely.

I proceeded to try something else. Twice I unplugged the hard drive, and reset the Tablo by pressing the blue button in the back. I tried to tune in the channel without the hard drive plugged in. This time I got a different error, “Playback Failed: No storage is available or accessible”. I tuned other channels (4-5) at random, and had no issues watching those channels. Tuned back the problematic channel, and got the error again. I then plugged back in the hard drive and waited a minute, tuned the channel and got the weak signal error this time. Like I said, I followed the above procedure twice.

I am really stumped why the Tablo would not allow me to watch this channel. FYI, I usually watch on my Roku, but this problem occurs on my phone and PC as well - the device used seems to play no role. I can’t imagine why this would only happen on one channel.

If anyone has any suggestions I would really appreciate it!

There is one possibility that may be easy to check. It’s very possible that your signal isn’t as strong as you think it is. Does your TV have a signal strength meter somewhere in its settings? If it does, check the signal strength on the channels you can receive on your Tablo and compare that signal strength to the signal strength on the channel you can’t receive on your Tablo. The Tablo divides your signal between the 4 tuners, so if your signal is near the digital cliff it may not be strong enough for your Tablo, but still strong enough for your TV.

If the signal isn’t over-amp’ed it’s then more about the sound to noise ratio and not the signal strength.

Some TV’s have a built in signal meter and some of these will also display the S/N. Tablo has an internal splitter so there is some S/N lose. Once the S/N ration reaches a certain level the signal is to weak - due to the higher noise levels.

And if you live in south western california I have no explanation why one low powered UHF channel went down the tubes 3 weeks ago. I thought it had to do with heat inversion levels caused by the temperature difference between the coast and 4 miles inland.

Luckily the older of the two TVs shows signal diagnostics:

Signal Strength: 65 (green)
Phys Ch: 14
Freq. 473000
Modulation: 8VSB
Status: Lock
Errors: 0
SNR (dB): 18
AGC (%) 64

I admittedly don’t know how to interpret these. How do these numbers look?

I’ll just add quickly, that last year this channel and the Tablo got along very well. I know things change, so perhaps the station changed something in their broadcast signal.

Thanks for the suggestions.

The 18 dB SNR is sufficient for the television tuners. The Tablo tuner is usually 3 dB SNR weaker than television tuners. At 15 dB SNR the Tablo will be right at the signal falloff cliff and fail in most cases.

If your antenna doesn’t have a preamplifier, adding a good preamplifier may boost up that 15 dB to 18 dB for the Tablo tuner to get that channel.

https://www.amazon.com/Winegard-LNA-100-Antenna-Amplifier-Booster/dp/B00BN5Z2UY/ref=sr_1_3?dchild=1&keywords=Winegard+LNA-100+Boost+TV+Antenna+Amplifier&qid=1625798245&sr=8-3

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I have little faith in S/N levels at 17 and below. The signal becomes to inconsistent.

Of course we haven’t even talked about whether this channel has the weakest S/N of all the channels and whether a mild change in antenna direction would have a positive affect on phys channel 14 and no real affect on other channels.

I would try a preamplifier.

Thanks for all the suggestions everyone. I’m going to do some more experimenting tomorrow and Saturday, and see where I stand. Now that I understand better where the S/N levels should be I’ll be able to compare other channels with the problem one. I’ll make an update on Sunday. If nothing else works I’ll buy a preamp next week.

If you go to tvfool.com, it will help you orient your antenna. It will also display what the possibilities are for each channel. All this also depends on what type of antenna you have.

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Sorry I never got back here like I wanted to. It turns out that the station in question is the only one that has such a weak signal. I didn’t find a new sweet spot. The place where I had the antenna is the best for the station. I was able to get a slightly better SNR (db) level, but was not good enough for the Tablo. It looks like a preamp is in my future.

Is that channel UHF or VHF? If the channel is VHF, does the antenna have VHF capability?

Does the TVFool report indicate how far that station is from your location?

The channel is UHF channel 14, and the transmitter is about 25 miles from me. I did learn one other fact: This is a LP station. I learned that this is the designation for lower power stations. I suppose any number of factors could be weakening the signal, even summer foliage.

A low power station typically provides coverage within a city radius of 10 to 15 miles. A preamp may add another 20 to 30% taking that station up to an acceptable level for the Tablo. But it has to be a good preamp with a 1 dB noise level (cheap preamps are at 3 dB noise levels and these noise levels wipe out any gain).

Aside from the Winegard one mentioned above, the best preamp is this one in the 1 dB noise range. This one will pick up stations when others won’t but is pricier.

http://kitztech.com/KT200.html

LP stations are often repeaters for a different station, for an area that can’t get the main station signal. Is that the case here? Can you get the main station?

From all the research I’ve done, it is the main station.

That’s unfortunate. You’re probably just out of luck then.

I have the same problem with weak signal on KTRK ABC13 in Houston. Im about 40 miles from the transmitters. thats the only channels thats gives me thiat Iissue installed a 4g LTE filer on the main antenna line. so far so good.