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From: depolo@eniac.seas.upenn.edu (Jeff DePolo)
Newsgroups: sci.electronics
Subject: Re: vcr recording
Message-ID: <27427@netnews.upenn.edu>
Date: 24 Jul 90 19:22:43 GMT
References: <1990Jul19.222558.7820@mozart.amd.com>
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Reply-To: depolo@eniac.seas.upenn.edu.UUCP (Jeff DePolo)
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In article <1990Jul19.222558.7820@mozart.amd.com> zahid@mozart.amd.com (Zahid Ahsanullah) writes:
>The symptoms are if you are viewing
>from the recording vcr end, a slight but periodic change in the
>brightness of the screen. This is not the case if you just want
>to view the movie.
>
>Any of you guys got any circuits out there? Really appreciate it.
>
>				Zahid

The varying brightness is characteristic of MacroVision, one of the better
anti-duplication schemes.  You may also notice a horizontal bar that
moves from the top to the bottom of the screen on your duplicate tape.

In any event, MacroVision can be defeated.  You can buy copy boxes for
about $50 that will take care of the problem or you can build one yourself.
Supposedly there was a recent article in Radio Electronics (I think) that
had the plans for one.  Total on the parts would probably run close to
$30 or so anyway, so it may be easier just to buy one.

Look in the back of Radio Electronics, Video Magazine, Video Review, etc.
to find ads for these things.

							--- Jeff

+-----------------------+-----------------------------------------------------+
|   Jeff DePolo N3HBZ   | Internet: depolo@eniac.seas.upenn.edu               |
| Univ. of Pennsylvania | RF: 146.685- 224.40- 442.70+ 144.455s (Philadelpia) |
| Computer Science Eng. | Twisted pair: (215) 386-7199 home                   |
|     Class of 1991     | Carrier pigeon: 420 South 42nd St. Philly, PA 19104 |
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