About a month ago, both my Sanyo and Samsung HDTVs (connected to antennas) began showing the time one hour behind. I figured whoever is sending the info had the wrong older dates for time change. Now that the time HAS changed, the TVs show the time 1 hour ahead! Where is this incorrect time data coming from? I know KTVT has the TV Guide info.
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Who sends out PSIP time info in DFW?
- Thread starter ropertex
- Start date
Frank Provasek said:
KERA had the time back in the analog era, but my understanding of PSIP is that each station sets its own time. That probably seemed like a good idea when DTV was being designed, but it wreaks havoc with tuners that don't have a way to set their internal clock aside from whichever station's time they pick to use (e.g., the DTVPal converter box), because a few stations always seem to have inaccurate times.
Correct...each station does send out the time, which can cause confusion when some stations have the time correct, and others don't. Some months back, I learned this the hard way when I tuned my OTA DVR through some of our local low power stations and it wreaked havoc on the timer recordings that I'd had set. Apparently, one of those LPTVs not only had the wrong time, but also the wrong year...
I did a quickie survey last night of every DFW station that has at least one English subchannel, and....
So if you want/need accurate time, you probably should delete KLDT/55 and all the low-power stations you can live without. (In my case that's everything but K31GL and MTV Tres on KATA.) Even then, you'll likely have some issues in March and November due to DST.
- All the full-power stations had the correct time, except for KLDT/55.
- None of the low-power stations had the correct time except for KATA/50.
So if you want/need accurate time, you probably should delete KLDT/55 and all the low-power stations you can live without. (In my case that's everything but K31GL and MTV Tres on KATA.) Even then, you'll likely have some issues in March and November due to DST.
coyoteaz said:
Do you mean EPG (Electronic Programming Guide)? That's the descriptions of what's on and what's coming up.
Digital TV won't work without PSIP as it includes important info like subchannel numbers, in addition to the date and time. But EPGs are an optional part of PSIP. I think full-power stations have to include an EPG but it seems none of the LPTVs do.
No, I mean PSIP. ATSC A/65. ATSC broadcasts technically work fine without PSIP, and since KATA's physical channel/program numbers are the same as the virtual channel/program numbers, no one really noticed that the PSIP disappeared. KATA has in fact been using DVB-T style metadata with a NIT and SDT instead of PSIP. I'm pretty sure that even LD stations are legally required to broadcast a virtual channel table, and I don't think the NIT/SDT counts for that since most ATSC receivers aren't going to be looking for it. KATA seems to be completely off the air at the moment, so perhaps someone is working on fixing it.
coyoteaz said:
Well, that's news to me. How were they sending an accurate TOD? I thought that was part of PSIP too.
That brings up an interesting bug. One specific converter box, a Channel Master CM-7000, insists on swapping subchannels 50.1 and 50.2. But every other tuner I've tried works fine. Could the CM-7000 be reading some of the funky metadata they were sending and getting confused?
They're back on the air now. Let me rescan and see if they've changed anything that fixes their program table on the CM-7000.
DVB has a TDT (Time and Date Table) which serves the same timekeeping purpose as ATSC's STT (System Time Table). I haven't been able to pick up KATA recently so I'm not sure exactly what they're doing at the moment, but from what I can tell based on other reports the PSIP is still not fixed.
They're back on but it appears they still aren't sending PSIP.
The CM-7000 was deceiving me. In fact w/o PSIP it doesn't pick up the time. Instead it sets an internal clock to whatever time it received last. So when I tuned from 52 to 50 it appeared to have the correct time. But I discovered if I tune from 51 to 50 it stays with 51's incorrect time.
The CM-7000 was deceiving me. In fact w/o PSIP it doesn't pick up the time. Instead it sets an internal clock to whatever time it received last. So when I tuned from 52 to 50 it appeared to have the correct time. But I discovered if I tune from 51 to 50 it stays with 51's incorrect time.
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