No Signal On One Channel

#1

I’m in Uxbridge, MA using a Tablo with an antenna in the attic. I’m getting all Boston stations (except 1) and most Providence stations as well. My antenna is pointed right at channel 38.1 (virtual), which had the weakest Boston signal for me the day I installed my antenna, which was months ago. I even get 2.1, by the way (WGBH actual channel 5). It’s a low VHF station, so I think I’m fortunate.

After re-scanning yesterday and today, I no longer see 15.1 or 15.2 (virtual channels). The folks over at the AVS Boston Antenna forum are saying that if I can get all of the other Boston stations, I should be able to see 15.1 and 15.2.

Here’s a quote from someone who is very knowledgeable over there on the repack, signal strengths and antennas:

“Something must be up with your Tablo if you’re not getting the WGBX signals at all, since they should be much stronger than many of the other channels where you are, WGBX has the following on their RF 32 signal:
2.2 GBH World
2.3 WGBH SD
15.1 WBTS HD (NBC Boston)
15.2 Cozi
44.2 WGBX SD
44.3 GBH Create
44.4 GBH Kids”

Evidently, the old 15.1 is now being sent using WGBX’s signal.

I can get both 2.1 and 44.1, but none of the other 2 or 44 sub channels. In other words, I only get 2.1, not 2.2 or 2.3, and only 44.1, not 44.2, 44,3 or 44.4. Weird.

I’ve re-scanned 3 times today, once after hitting the blue ‘reset’ button on the Tablo. Is there something else I can try?

#2

Is it possibly a Tablo guide problem (with so much channel shifting these days)? Can you see these channels when antenna directly plugged into the TV?

Also Tablo has problems with channels whose PSIP is not what the Tablo expects. Because of the repack, could those channels have gotten non-matching or unexpected PSIP data?

#3

15.1 and 15.2 apparently changed frequencies on Sunday, so it could be that.

As for hooking the antenna to my TV, that will take some doing - the Tablo is in a room with ethernet but no TV. I’ll have to run more RG6 to hook the antenna to the TV, or bring the TV into the room where the Tablo is. Good idea, though.

I may have time for that tomorrow - I’ll post back my findings.

#4

TVs are more forgiving of bad PSIP or guide data. I did have one channel several years ago that had a bad header in the stream; the station had to fix that. My DVR would not read the stream, my TV did OK.

#5

This BTW is an excellent video regarding continuing repack problems:

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#6

@MarkKindle Thanks. The Antenna Man YouTube channel is always full of great information. My repack does not happen until year end. Hopefully things will go well.

#7

This may be a mis-statement. Your TV needs a coax to connect to your antenna. RG6 is for your internet/network connections.

After one of the repacks in my area, one of the channels moved from the UHF frequencies to a VHF-LO frequency. The flat UHF antenna I was using did a poor job of picking up the VHF-LO signals.

By connecting your antenna directly to your TV (via coax), you can determine whether your antenna is working properly or not, for your missing channels.

#8

@DrJack - Uh, no, RG6 is coax for cable, satellite and antenna installations.

The channels in question for me are still on UHF.

And I do plan to move our smallest TV into the room where the Tablo is to test sometime today.

#9

Great news!

I decided to do one more scan this morning (7:45am Eastern) before moving one of our TVs into the room where our Tablo, antenna lead and wired internet converge. Now I’m getting all of the channels I listed in my OP and more!

I’m also getting for the first time:

WMUR 9.1, 9.2
13.1, 13.2, 13.3 - CBS, TBD, Stadium respectively

I have no idea yet where channel 13 is coming from lol.

Maybe it’s they are back on full power, or it’s a little cooler and less humid this morning (60 degrees). Now that they are all in my guide I’m good to go.

Thank you all for your input on this.

#10

I’m in western Middlesex County, MA and am not getting 2.1 or 44.1 any more but am getting 22.2, 22.3, 44.2, 44.3, and 44.4. I checked directly with my TV’s tuner as well as with the Tablo.

#11

2.1 (WGBH, real channel 5) is low VHF now having changed frequencies due to the repack several weeks ago. Is your antenna LO VHF capable? Many users at the AVS Forums Boston thread are complaining about this. WGBH is also petitioning the FCC for a power increase because their LO VHF signal is not reaching everyone adequately.

What antenna do you have?

#12

So the sub-channels are broadcast on a different frequency? Interesting. I suppose it’s an advantage of virtual channel numbers.

I’m currently using a Mohu Leaf 50 (aka Leaf Ultra) which seems to have a VHF range of only 20 miles, and is therefore now insufficient for my needs. It looks like I’ll need to install the Mohu Air 60 (the Best Buy variant of the Mohu Sky 60) I bought a while back.

I’m glad to hear they’ve requested an increase to transmitter power. I expect many people would benefit, if it’s permitted.

#13

However this is low VHF, not just VHF. A low VHF capable antenna is much larger than a high VHF capable antenna. Is the Mohu Air 60 low VHF capable? It’s not just range (distance) but frequency wavelength (low = channels 2 to 6). One Boston user went with the Winegard HD7000R which has a low VHF element in order to get channel 5.

If you’re within 20 miles, for that one channel try a simple rabbit ears antenna fully extended for $10.

BTW there is a discussion of low VHF with a MA user @ericgus and several low VHF alternatives (different antennas such as a wire dipole) in the Antop Antennas! thread (of all places).

#14

No the different sub channels are not on a different frequency. ALL of WGBH’s channels are on RF 5. WGBH took the cash to switch to a worse frequency, and now their OTA customers are suffering because of it.

#15

Of course PBS has a streaming channel for $10 a month (and up) to get all the programming…:money_mouth_face:

#16

Ok. But what would cause the *-1 HD subchannels to not be detected while the SD ones are?

#17

2.2 and 2.3 are UHF channel 32.

See this chart:

https://www.rabbitears.info/market.php?request=print_market&mktid=8

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#18

OK, I’ve never seen that before. The “display” subchannels are from different RF sub channels. Weird.

#19

Ah. I see. Thank you for sharing that.

#20

As @MarkKindle mentioned above, you can try plain, old fashioned rabbit ears (fully extended) to try and get ch 5 (WGBH) if you are 20 miles from the broadcast tower. I have gotten low VHF that way previously in another market. I was 12 miles from the broadcast tower.