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From: lauren@vortex.UUCP (Lauren Weinstein)
Newsgroups: net.news.stargate
Subject: Re: Will A VCR muck with STARGATE?
Message-ID: <529@vortex.UUCP>
Date: Tue, 29-Jan-85 16:23:26 EST
Article-I.D.: vortex.529
Posted: Tue Jan 29 16:23:26 1985
Date-Received: Fri, 1-Feb-85 21:38:37 EST
References: <70@cithep.UucP>
Organization: Vortex Technology, Los Angeles
Lines: 21

Because of the low quality of most consumer VCR equipment (they are really
much lower quality than most people think, but people will accept
a lot of garbage in their picture), those machines are not suitable for
data recordings.  I've experimented with this myself.  You can
forget it completely on Beta and VHS machines.  You are lucky to be
able to record the closed captioning on 1/2" VCRs (and there are only
2 (TWO!) bytes per field for closed captioning.  A U-MATIC 3/4"
VCR can record some data so long as the color is stripped out (or
you are recording a monochrome program).  With color on, the bandwidth
is too narrow and the data is smashed.  Even in monochrome, the data
error rate is very, very high, but you get a little of it.  A good
professional 1" VCR (type C, for example) can usually record some or
all of the data successfully.  But these are not consumer machines,
of course.

The cabletext data bits are impressed on the signal at a steady
5 Mhz. rate.  "Inexpensive" VCRs, which have sacrificed picture quality
for recording time, simply cannot deal with other than VERY low rate
data.

--Lauren--