22 Jan
2015
22 Jan
'15
10:34 p.m.
On Fri, 23 Jan 2015, tony duell wrote:
Doing such a thing would have an appreciable chance of causing damage to
the modulator because it's feeding into something that's probably not
tuned to precisely the right frequency. Antennas designed only to receive
tend to be very poor for transmitting.
--
David Griffith
dgriffi at cs.csubak.edu
A: Because it fouls the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?
1) When hooking this up to a TV via the RF input
- is there any "magic"
involved, or will a suitable braided co-ax TV cable with a phono connector
added at the Atari end do? I know it "works" because I lashed one up
Maybe... The modulator output is nominally 75 ohm, and should be linked to
such a piece of coax. European TVs have a 75 ohm aerial input, often on what
we call a 'Belling-Lee coax socket', so it's just a cable. US TVs, I am told,
may have
either a 75 ohm coax input, often on an F connector, or a 300 ohm balanced input
(for parallel twin feeder cable) on a pair of screw terminals. For the former, just
connect it up. For the latter you may need a matching transformer, aka a 'balun'
(BALanced to UNbalanced converter). I am pretty sure you can buy these, but
it must be possible to wind one if you can get a suitable core
The European switch box is just a switch. The US one I have somewhere has
screw terminals for the aerial input, a bit of twin feeder for the output and
IIRC a phono socket for the computer RF input. There is a balun inside.
The switch is special too. It is designed to minimise RF leakage from the
computer to the aerial, since linking an aerial to the computer modulator
output would make a very low power TV transmitter. How far it would be
detectable I do not know, but the FCC (or whoever) take a dim view of
such things.