Gemstar VCRPLUS clock accuracy

My recorders got the correct time/date from the tv teletext.

Hi!

Time information is sometimes broadcast alongside whatever programming a station is normally running. A public television station in your area will typically be the source, although some commercial stations broadcast the time as well. The devices might be able to get their time from that signal.

However, the cessation of analog broadcasting may mean that at some point the automatic clock setting function that these devices may use will no longer work. I have yet to see a digital converter box that passes or converts the time signal so that older analog-only reception equipment can still set its clock automatically. All stations broadcasting digital TV (ATSC) appear to be sending time signals, but the ones I've seen are not all correct. Most of them are off by quite a ways.

William

No, this is a stand-alone unit much like a remote control for a TV. You enter a VCRPlus code into the unit and it turned on your vcr and changed the cable box to the correct channel for recording.

Thanks for responding, but the Gemstar unit is not a recorder, it is a smart remote control which runs on batteries.

Oh so its kinda like a remote that you just set the record time on and it does the rest without having to use the OSD menu to set everything on the VCR. There was a similar product sold "AS Seen on TV".

Hi!

If memory serves, some of that technology was used in VCRs, but thanks for clarifying. I'm pretty sure that I've seen a few of those remotes, although I've never been close enough to examine one. (Nor did I really have any reason to do so.)

I wouldn't think that the clocks inside these devices could be that accurate all by themselves. The use of a separate battery or packaged circuit for timekeeping purposes seems unlikely, although I suppose something like a capacitor could be used to keep the clock running while the batteries are changed.

I suppose it could always get the correct time by way of the radio signals that come from a centrally located time standard, such as an atomic clock. That would actually be a pretty good way of obtaining correct time and date information.

William

The things are too old to pick up such signals. The clock is amazing, and all by itself.

Hi!

Actually, they're not. Both the technology and broadcast have existed for quite some time now, possibly as far back as the 60s. Radio controlled clocks are both popular and cheap today, but the time broadcast predates the sudden proliferation of these devices.

Quartz battery operated clocks can be very good timekeepers, but they're not perfect no matter how much care is put into making one.

William

They used the power line for frequency source.

Let's say his device had a horrible clock design that was only guaranteed accurate to +/- 10%. He could still happen to get the

No, I have several of these and they all keep perfect time. I don't expect we'll get an answer here, but the devices are something special.

What is "perfect"? How do they compare to "network time" (NTP)?

Basically, if they are not regularly synchronized to an external time standard, there's pretty much zero chance that they're going to show zero long-term rate error.

Isaac

They're so special that you can't provide us with a model number?

I said in my original post, after twenty years or so, the clocks are correct to within a minute. The only setting I ever did was to change the hour +/- to effect the season change.

Sure, the first unit I picked up was a Gemstar VIP-18. I think there a previous unit VIP-08. It is 7"x2.5"x.75" and runs on 4 AA cells. The unit was (c) 1990.

Do the units display a time? Or are you going by the fact that the VCR that it's controlling works properly?

If it's the latter, that's because VCRplus is just a compression scheme for time and channel and the unit translates that with a fixed algorithm and sends the programming setup to the VCR. It's the clock in the VCR that matters.

Mark Zenier snipped-for-privacy@eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)

Hi!

I see there's one on eBay at present that would cost a princely $3 and shipping to buy. I'm half tempted, just to crack it open and answer your question.

There are good battery operated quartz clocks, and some of them will keep very good time. But if those things have stayed accurate to within a minute over twenty years, they *have* to be getting a time reference from somewhere. Battery operated clocks just aren't that stable over long periods of time because of a lot of factors, not the least of which is battery drain over time.

(Power line clocks, on the other hand, can be startlingly stable.)

The technology would most certainly have been available for those remotes to listen to the WWV time data broadcast. And it would be a good feature to put there, since many broadcasters and networks synchronize their clocks to that standard as well. That way there could not be any real drift between what time it is and what time the clocks around your house say it is, and no problem with programs being "clipped" by differing time settings.

The way I see it, it makes perfect sense to have done it that way.

William

Correct to within a minute? Hmmm...figuring that the time would be fiddled with each time the batteries were replaced (and perhaps at each time change), that seems reasonable.

Again I didn't make myself clear: The unit allows you to set the hour without setting any other value. That is the only change I ever did. Twice a year I would set the hour to adjust for daylight/standard time. The unit held all values when the batteries (4) were changed.