Re: [time-nuts] TV Signals as a frequency reference

Yeah, that's pretty much the story around the country. I also have some monitoring software (monitoring PSIP, video and audio data, not specifically for monitoring STT packets) that I run on the Denver and Cheyenne stations 24 hours a day. Very few have set their GPS-UTC offset to 18 seconds. 

[time-nuts] TV Signals as a frequency reference

Here's a local guy's take on monitoring time and DST errors on the stations in the Dallas area: http://home.earthlink.net/~schultdw/atsc/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] TV Signals as a frequency reference

I wrote a program that would scan the PSIP data from my local stations and the STT was always quite poor. Usually several stations had the GPS-UTC offset that was stale, even a year after a leap second. It would be trivial to make an automatic correct STT generator some online data (NTP, etc.),

[time-nuts] TV Signals as a frequency reference

I read that there is a requirement that the time data in the PSIP data stream has to be within one second. I have an over-the-air DVR that would mess up the time and recordings because it was originally not filtering the times the stations broadcast. They finally modified the DVR firmware

Re: [time-nuts] TV Signals as a frequency reference

I was a chief engineer for a TV station during the transition to digital. I am now a transmitter supervisor for two digital TV transmitters. None of the stations in my area have a frequency standard. Time in injected into the digital stream usually from a pc clock. This pc may or may not be

Re: [time-nuts] TV Signals as a frequency reference

In the mid-1970's (when I was an EE student in college) I built a simple setup to compare the US color burst signal (3.5795454.. MHz) from an old vacuum tube color television set with a commercial surplus 5 MHz OCXO (probably from Bliley). The color burst frequency was exactly:315/88 = (63 *

Re: [time-nuts] TV Signals as a frequency reference

Yes I actually purchased two such devices from Ebay a while back. (They contained nice PRS10 Rb oscillators.) Mark Spencer Aligned Solutions Co. m...@alignedsolutions.com 604 762 4099 > On Mar 31, 2018, at 12:09 PM, Ruslan Nabioullin wrote: > >> On Sat, Mar 31, 2018

Re: [time-nuts] TV Signals as a frequency reference

Dana...   Back in the day when out of studio news stories were shot on film, which was then processed at the studio  and broadcast from a "film chain" stations would lock their sync generators to the incoming network signal during network hours.  That allowed "clean" switching in and out of

Re: [time-nuts] TV Signals as a frequency reference

I grew up in the 50s and 60s watching the lines at the top of the TV screen change in black and white segments according to their coded information. My Dad had adjusted our set so he could see those lines. (He was a field service specialist for Canadian General Electric.) I think the

Re: [time-nuts] TV Signals as a frequency reference

On Sat, Mar 31, 2018 at 9:38 AM, Bob kb8tq wrote: > You probably would do better to build a gizmo to pull timing off you local > cell towers. > The hardware to do it is relatively well documented. As long as you are > careful about > which system you use, the timing should be GPS

Re: [time-nuts] TV Signals as a frequency reference

Hi To a great extent it depends on who was running the tech side of things. If the guy in charge dug into it, they may have had a pretty fancy timing setup. If it was a “don’t bother / don’t dig / not very broken” sort of thing, the setup may have been pretty crazy. Bob > On Mar 31, 2018,

Re: [time-nuts] TV Signals as a frequency reference

When the transition to digital only happened, I happened to ask a ham friend who was chief engineer at the local Fox station what they were doing with all their gear. He said probably taking it to a hamfest. I said if you chuck your rubidium or cesium standard let me know. He started laughing

Re: [time-nuts] TV Signals as a frequency reference

On 3/30/18 10:43 PM, Hal Murray wrote: As noted earlier, color burst references were a big deal a long time ago. Thanks. I was fishing for something modern, maybe a bit clock out of the digital receiver. I'm assuming that the digital stream is locked to the carrier. That may not be correct.

Re: [time-nuts] TV Signals as a frequency reference

Hi My comments really were a bit brief…. indeed there *are* clocks in the modern signals. Those clocks come over as part of the signal you get. The must be a way to build something that would get at those clocks. You still have the same basic issue as with the “old” signals. Does it go

Re: [time-nuts] TV Signals as a frequency reference

I'e always been curious as to why TV stations did not lock at least their in-house equipment to the network feed as a means to avoid spending money on frame syncs. Remote coverage, on the other hand, would of course open a new can of worms. But compared to the cost of building and powering a TV

Re: [time-nuts] TV Signals as a frequency reference

Hello all...     One limitation, back in the day, when the network signal was being passed thru to the local markets...   Many stations used a frame sync to time the network signal to the local house signal.  In other words the network reference was stripped and retimed to the house so as to avoid

Re: [time-nuts] TV Signals as a frequency reference

> As noted earlier, color burst references were a big deal a long time ago. Thanks. I was fishing for something modern, maybe a bit clock out of the digital receiver. I'm assuming that the digital stream is locked to the carrier. That may not be correct. -- These are my opinions. I hate

Re: [time-nuts] TV Signals as a frequency reference

Am 31.03.2018 um 00:13 schrieb Hal Murray: fgr...@otiengineering.com said: Now that analog TV has gone away, so have these signals. What do the local TV stations use for a frequency reference? Are there low cost receivers that also produce a good reference frequency? The German

Re: [time-nuts] TV Signals as a frequency reference

Hello to the group. Been staying clear of the thread as many good comments. Several things happened that made the color burst signal useless for most people. Yes the networks had Cesium's about 3 of them at CBS and the network feed carried that quality. but about 1980 a device called a frame

Re: [time-nuts] TV Signals as a frequency reference

On 3/30/18 5:52 PM, Bob kb8tq wrote: Hi On Mar 30, 2018, at 6:13 PM, Hal Murray wrote: fgr...@otiengineering.com said: Now that analog TV has gone away, so have these signals. What do the local TV stations use for a frequency reference? Anything from a

Re: [time-nuts] TV Signals as a frequency reference

It might of been fairly easy to use an old NTSC television signal as a frequency reference (lumina, chroma or audio carriers). Now that it is converted over to ATSC it would be much more difficult to recover a reference frequency using readily available electronics. You would have a much better

Re: [time-nuts] TV Signals as a frequency reference

Hi > On Mar 30, 2018, at 6:13 PM, Hal Murray wrote: > > > fgr...@otiengineering.com said: >> Now that analog TV has gone away, so >> have these signals. > > What do the local TV stations use for a frequency reference? Anything from a crystal oscillator to a Cs

Re: [time-nuts] TV Signals as a frequency reference

fgr...@otiengineering.com said: > Now that analog TV has gone away, so > have these signals. What do the local TV stations use for a frequency reference? Are there low cost receivers that also produce a good reference frequency? -- These are my opinions. I hate spam.

[time-nuts] TV Signals as a frequency reference

Hal Murray (hmur...@megapathdsl.net) said: "Roughly 40 years ago, a friend showed me a NBS booklet describing a scheme for distributing time via TV. I forget the details. It was a cooperative project with one of the major networks. NBS published the propagation delays which changed