Herbarius, on Tue Dec 29, 2009 4:49 PM, said:
Even that old B/W TV I spoke of had the normal coaxial plug - being optional as it also had and included antenna (that telescope-style antennas you know from radios). So regardless if you have cable TV or still use "air waves", you had the same coaxial RF plug.
Europe uses a completely different RF plug from the US. The US uses the screw-on F connector, which is much more reliable... except that cheap connectors have a loose screw part, which makes the ground less good. I have only personally seen the Euro RF connector on an O^2 unit. (and on a PAL TV that I found in a thrift store years ago... which I promptly replaced with an F connector because it was easy to change) And if you're considering a whine about having to screw them all the time, there is a slide-on variant of the F connector.
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What about the assignment of number to station? Are those constant (assuming the station doesn't cease to exist) or do they change sometimes? Here every few years they'll shuffle them all around for some reason and you've to reprogram your TV - the cable provider will send out letters a few weeks in advance... (including some blabla to explain why they changed it, but it sounds rather like made-up reasons if you ask me...)
The non-adjacent channels were to avoid interference. (How the hell did you drift that into ID cards?) When you have a few thousand TV transmitters, and two long borders with other transmitters not under your control, you need channel allocation rules to avoid interference.
NTSC had enough bleed-over around the edges of the 6 MHz channel that it would cause signal quality problems over the air. (There's other adjacency rules that I didn't mention because they are more obscure.) Cable TV didn't have atmospheric effects and reflections off of buildings and distant stations 200 miles away to deal with, so they could use every channel. And the FCC doesn't control the cable TV signal since it's not being broadcast over the air. Not that cable was trouble-free... if you put an OTA station on the same channel, people living near the transmitter or with a weak cable signal would get interference between the two nearly identical signals. A few years ago a channel 5 (the lower frequencies show this problem the easiest) in San Antonio insisted that the cable company move them off of 6 and on to 5. At least now it doesn't matter.
And the towers keep the same channel as long as they are licensed. Sometimes a station will change networks, but the transmitter stays the same. And it's exactly because of this that the FCC needs to assign channels for new stations so that they don't interfere with each other. Commercial transmitters are custom-built to a single frequency, and they can't be simply re-tuned to another channel.
In the UK, there are only a few networks, mostly BBC channels, that are rebroadcast all over the country on multiple transmitters, so if all you did was pre-tune your channels, you wouldn't know what channel freuqency you were getting, just that it was BBC3. Presumably they had similar allocation rules, but you just wouldn't know it. Really big cities like Los Angeles and Dallas/Forth can have over 20 or so network and independent channels broadcasting around the area.
I do have a problem with something about the digital transition. The signal can claim to be a different channel than it is being broadcast on. This made sense when a station had two transmitters during the transition. But most stations did not go back to their original frequency. I can understand
allowing them to keep using the original number for "branding" purposes, but apparently they are actually forbidden from changing to their new number if they want to, which I think is stupid. There's even one station in Waco that was 25 analog, stayed on their 26 digital, IDs as 25, but one of the sub-channels has a "bug" in the picture that says 26.
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I don't really know what you mean with 12-button or 16-button tuner... But you are right, here we have large "chunks" of unused frequencies you could as well skip over when searching for channels.
That PAL TV I found at a thrift store was a 16-button tuner. Just a bunch of fixed buttons, and you manually tuned each one of them to a channel. Then you could just label the buttons BBC1, BBC2, BBC3, etc. if you wanted. Also, by being a "slider" tuner, it would be sellable in more PAL countries that used different specific channel frequencies.
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This of course is rather a problem with the nature of RF in itself - surely one of the reasons why the FCC has so strict regulations about it. It's obviously damn hard to shield anything against it. You'd think a real "switch box" should completely lock out you normal TV programme, but in reality I never seen one that really does that.
What? The problem is that if there is a local station on the same channel, the very wires you use to connect to the set, and even inside the TV set, can be a sufficient antenna to pick up a weak signal from that station. If the local channel is strong enough, your game's picture will be bad and you can't do anything about it.