Does specific tuner card affect quality or reception?

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Jessica12345
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Does specific tuner card affect quality or reception?

Post by Jessica12345 »

I'm running with 2 Hauppauge dual usb tuner cards (so four tuners total). They work fine, I guess, except that I'm losing about 25% of my recordings due to poor signal quality, i.e. the signal gets choppy and freezes. Usually mythtv flags these recordings in yellow to indicate that it didn't record well. I live in Chicago, very close to the broadcast towers, so it may be interference or shadows from all of the tall buildings around me. I've tried different antennas, different locations for them, some are definitely better than others, and also tried filters to attenuate the cell signals. One thing I haven't tried is a different tuner card. Does anyone think that might make a difference? Maybe some cards might be better than others at maintaining a lock in the signal or something? I don't really know how they work, maybe it is a stupid question. Any advice would be appreciated.
white_haired_uncle
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Re: Does specific tuner card affect quality or reception?

Post by white_haired_uncle »

Yes, some tuners are better than others. And maybe one of yours is bad.

Assuming you use the default theme, you can choose a recording and hit 'i' twice to see which tuner was used by a recording. Be interesting to see if there is a pattern. You could also use recorded.inputname and recordedprogram.videoprop to pull this from mysql.

I'd also look to see if there's a pattern on which channel(s) have problems. Could be a clue if most are on a single RF, or if most are VHF or UHF. I assume you're using a splitter, it'd be interesting to see if your problems tend to be one on of the outputs (oh, and terminate any unused ports).

I don't know what's up in Chicago, but about a year ago the frequencies above channel 35 were given over to 5G, so if you have an older LTE filter you might need a new one (should filter down to right about 608 MHz vs 695 for the old ones). Or it might not make any difference, often you'll never know. I have an FM trap on mine as well (FM radio lives between RF channels 6 and 7, but can interfere with channels outside that range).

If you're close in, an amplifier is probably to be avoided.

A cable ground can help eliminate noise, even if you don't technically need one for code reasons (I used to lose all my VHF channels when I turned on my garage light until I grounded the coax just off the antenna).

ATSC3.0 should help if your issue is multipath (signal reflects off buildings, so you end up getting the same signal coming from different directions at just ever so slightly different times), but the broadcasters are slapping DRM on many of those channels so I don't expect DVR support (certainly not FOSS) any time soon.

I'd strongly recommend you go to https://www.avsforum.com/forums/local-h ... eption.45/ , read the post at the very top, and then post a call for help in the Chicago thread. Great place for info about local issues.
Jessica12345
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Re: Does specific tuner card affect quality or reception?

Post by Jessica12345 »

Thanks so much for your reply, this was a lot of really helpful information. The avsforum site was really helpful and I think it led me to the solution (maybe). There was a post about needing a UHF/VHF combination antenna in order to receive certain channels, which were exactly the channels that I've been having trouble with. I had been using an old laminate antenna on one of the tuners, it seemed to be the only antenna that could receive those channels. They recommended using a rabbit ears and loop antenna, so I picked up one of those. I also picked up an astc3.0 tuner box, it seems to be working so far. Only time will tell if it fixes the problem, but based on a channel scan, the new antenna does pick up those channels that I had been having trouble getting, so it's a good sign.

Thanks!
mathog
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Re: Does specific tuner card affect quality or reception?

Post by mathog »

Just a small comment. If a person has N tuners and 1/N of the recordings are bad it would be worth going through the log files to see which tuner was used for each of the bad recordings. It is quite possible that a particular tuner is going bad (or its external power supply is), or it could be that the antennas are different on some of the tuners and one antenna/tuner combination does not work for a particular station. If the hardware is failing then replace it. (We have replaced our HDHomeRun's external power supply twice.) If only certain antenna/tuner combinations work for a particular station, then specify those rather than using the default "any tuner". (At least I think that is possible, we have a dual HDHomeRun on one antenna, so it never came up for us. Using MythWeb to schedule there is "preferred input".)
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