Cannot Acquire Certain Broadcast Stations

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mfitch
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Joined: Sun Aug 17, 2014 1:25 am
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Cannot Acquire Certain Broadcast Stations

Post by mfitch »

Hello!

I just built a MythTV system to receive OTA broadcasts in my area. I have my backend equipped with a Hauppauge 1609 PCIe quad tuner card running Ubuntu 20.04 since this is what Hauppauge says is supported by their PPA.

I'm in the US so I set up my system to use ATSC. Everything seems to work fine except I am missing some broadcast stations like CBS, NBC, and ABC. These stations are detected with the same antenna directly connected to my TV (my TV does channel scans too if it has an antenna attached). I get other channels like Grit, MeTV, and Fox ok.

I searched the forums and didn't see any other people having a similar issue. Anyone know something I can try? Thanks!
white_haired_uncle
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Re: Cannot Acquire Certain Broadcast Stations

Post by white_haired_uncle »

Does your TV get them on ATSC3.0 or 1.0? Could be your TV has 3.0/DRM support, but your card doesn't, and for some reason you're not getting the 1.0 for those. Kind of a long shot. Or perhaps the tuner on your TV is more (or less, in case you're using an amp where you shouldn't be) sensitive and some channels are on the cusp.

When you say "same antenna" are you using a splitter/tap to connect both TV and card at once, or moving the cable (not sure what you mean by "directly")? Often you don't get the same signal loss on each output, so if you're splitting you might try switching the TV/card cables at the splitter.

I'd go to

https://www.avsforum.com/forums/local-h ... eption.45/

read the first thread at the top, and then check out the thread closest to you. It'd be interesting to see what rabbitears shows for your location.

There's probably a 'timeout to acquire lock' setting somewhere in myth for your card, could be that needs to be increased. I've seen it, but never had to mess with it.
mfitch
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Re: Cannot Acquire Certain Broadcast Stations

Post by mfitch »

My TV is pretty old (2011?) so I doubt it supports ATSC3.0, but I don't know. Yes, I do mean that when I connect the antenna to the TV's 'TV input' / coax port, the TV is able to scan and find the channels. I'm not using a splitter to connect to the TV or the PCIe card in my server; I physically move the connection from one to the other.

Here's the report from RabbitEars: https://www.rabbitears.info/s/1115581

It seems that ABC has a 'Fair' rating but my TV's tuner picks it up just fine so I suppose it should be good enough to get picked up by my PCIe card too. I'm going to try what you suggested with increasing the timeout value. Thanks for that!
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kmdewaal
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Re: Cannot Acquire Certain Broadcast Stations

Post by kmdewaal »

You can try unchecking the "Complete scan data required" option in the Channel Scanning page. This option is checked by default. It could be that this option causes some of your channels to be discarded. See WIki https://www.mythtv.org/wiki/Channel_Sca ... annel_Scan
gnurocks
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Re: Cannot Acquire Certain Broadcast Stations

Post by gnurocks »

I'm sure you did, but re-verify that you selected "us-bcast" before your scan. I found out the hard way that this has an effect. Otherwise, your scan will result in minimal or no channel pickups. General->Local Settings->Channel Frequency Table->us-bcast
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