billp@azure.UUCP (Bill Pfeifer) (01/11/84)
Most VIC-20 or Commodore 64 installations that I have seen have noise on the
TV screen that ranged from noticable to absolutely intolerable.
Here are some tricks that I have found effective in reducing that noise:
Don't use that blasted balun that comes with the computer! (That's the little
box that has the "computer - TV" switch). If your TV has a coax antenna input,
connect the RF cable from the computer directly to it. (Radio Shack sells an
adapter for that).
Some TVs have a switch on the back near the antenna terminals that allows
you to disconnect the TV's internal balun when using the coax input.
If your TV does not have such a switch, you will probably get some more
improvement by unsoldering the internal balun from the tuner. Do this only
if you feel comfortable with a soldering iron and don't want to use the
300 Ohm antenna input any more.
A large improvement is usually obtained by using a ferrite core on the RF cable.
Buy a 2 1/2 to 3 inch diameter ferrite core, as used in toroid transformers,
and wind the RF cable on it as many turns as possible.
This will kill any garbage travelling along the shield of the cable.
When I first connected my C64 to my TV, the noise was so bad, that even though
I knew that it said "READY" I couldn't read it. Now I have to look close to
see any noise at all. I would say that each of the above steps (direct
connection, removing the internal balun, using the ferrite core) contributed
about 1/3 to the total improvement.
Bill Pfeifer
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