EEVblog Electronics Community Forum
Products => Computers => Vintage Computing => Topic started by: aqarwaen on December 19, 2019, 12:21:44 am
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i rember that sometimes i could see my neighbour playing games on nitendo or what ever it was..
did anybody had issues that tv keept catching ohter tv signals or picture??
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That was fairly common in the days of RF modulators back before TVs commonly had baseband inputs. An RF modulator is effectively a low power transmitter and a poorly shielded connection or someone wiring it incorrectly could feed the signal to the antenna and turn it into a TV broadcaster. Early VCRs were notorious for this as well, I knew someone who used to occasionally get the neighbor's porn on his TV.
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Once upon a time, back in the Neanderthal period, TVs had a single input: the antenna.
If you wanted to connect other video devices, namely game consoles or VCRs, you had to do so thru the antenna input.
Therefore those devices would modulate their video to an RF channel. In North America it would be either ch 2, 3 or 4. (55.25, 61.25 and 67.25 Mhz respectively).
To switch between video sources, one would have RF switches and lots of coax cable.
Some poor installations could leak RF signals, which probably was what you were picking up.
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Do shared aerial/coax apartment complexes use passive tee splitters or proper amps?
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I so remember doing that! In our 1980's (broke) student house, we could position the loop aerial of our tiny Russian made B&W television flat against the wall, and tune into the video recorder in the house next door. Those people rented some real garbage on VHS, but their video nasties were all our cathode-ray-tube generation had to watch for free.
British and Irish UHF modulators were on channels 36 thru 39, a bandwidth reserved for air traffic control radar and radio astronomy users. Then the government of the day sold this 'slot' to Channel Five TV, which brought herringbone interference to many a living room in the London area; which spawned an industry of people who could retune clueless persons video recorders and televisions, for a fee.
btw During periods of Tropospheric ducting, that tiny Russian TV had a front end sensitive enough to receive transmitters on the Dutch coast; mostly british programmes with dutch subtitiles.
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Doing this on purpose was called Van Eck Phreaking (https://en.wikipedia.org/wiki/Van_Eck_phreaking).
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In my student days I remember hearing about some unfortunate fellow living in a block of fifty apartments who decided to watch some porn on his new VCR. Unfortunately a) the apartment block was fitted with a poorly designed antenna distribution system and b) the porn viewer had incorrectly wired his VCR.
The end result was that his VCR signal swamped the incoming RF and all fifty apartments received the same signal, with nothing else viewable.
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Back when mobile phones were analog, you could sometimes pick them up by tuning an older television to the upper UHF channels (70 to 83) whose frequency range had been reallocated from TV to cell phones.