This is the sixth in a series of articles about my recent quest to replace a broken VCR in this era of DVDs, DVRs, and other newfangled gadgets. Click here for the beginning of the series.
When cable TV systems first came along, they typically transmitted about 30 channels of television through the cable. In order to receive these stations, you needed a cable box. The first cable box we had was about the size of a book. It had a slider switch with about 30-some positions on it numbered 2 up to 40 I believe. The cable was a coaxial RF cable just like you would use to connect a roof antenna to your TV. It would come from the telephone pole at the back of your house into your home. From there it generally went through the attic, down the wall and exited out a small plate in your wall. You would connect that to the cable box and another coaxial RF cable would connect the cable box to the antenna connector on your TV set. You would set your TV on channel 3 or channel 4. Because Channel 4 was already occupied in this area we always used Channel 3 for connecting external devices such as cable boxes or VCRs. You would then position a slider lever on whatever channel you wanted to watch. There was also a small thumbwheel on one side that you would use as a fine-tuning wheel because the mechanical tuner did not accurately select the proper frequencies.
There was no remote-control capability. The slider box generally had a very long cord on it that you have to route behind some furniture or drape across your living room floor where you would trip over it.
You would think that if you already had a TV that could tune channels 2-83 that you wouldn’t need an external tuner to get channels 2-40. The problem is that cable TV systems use different frequencies than broadcast TV. Keep in mind when I said earlier that a channel number is NOT like the frequency on a radio dial. If you turn your FM dial to 93.1, that is an actual frequency in megahertz. The number of a TV channel has no mathematical relationship to the actual frequency used. They could have designed radio with channels and said that for example radio channel 17 would be assigned to specific frequency like 93.1 but that’s not how radio was designed. Television was indeed designed that way. The channel numbers are just arbitrary positions along a frequency spectrum.
It’s difficult to get UHF frequencies to travel along a cable. VHF frequencies travel much better. In cable TV systems, channels 2-13 are identical to the broadcast VHF channel frequencies. If all you wanted to watch on cable TV was channels 2-13, you could simply plug the cable directly into an older TV set and it worked just fine. Cable channels 14 and higher are a completely different set of VHF frequencies that are lower than UHF frequencies. Also I mentioned that there is a gap between channels 6 and 7. Some cable TV systems put as many as five different channels in frequencies in that gap.
One early alternative to the cable tuner box was a gadget called a “block converter”. It was a little electronic device you could buy at TV/video stores. It would convert VHF cable channels 14 and upwards into UHF frequencies. You can then use the UHF tuner on your TV or VCR to access all of the cable channels. The problem was the block converter was only good up to about channel 35 or 36. In the early days of cable, Comcast only had about that many channels but Time Warner cable (which is now called Bright House cable) had about 40 channels so the upper few channels with a block converter didn’t work very well with Time Warner systems.
Eventually they began producing TVs and VCRs which were advertised as “cable ready”. These were remote-control TVs and VCRs with electronic (non-mechanical) tuners that would precisely tune the proper frequencies for not only VHF and UHF broadcast channels but most if not all VHF cable channels. Initially they advertised them as “108 channels cable ready” or perhaps 109. Various cable systems throughout the country use different sets of channels and not all “cable ready” devices worked with all cable systems. Eventually TVs and VCRs which had 127 channel cable ready tuners were created and they worked with all cable systems in existence.
For those of us who struggled through the eras of clunky mechanical channel changers, fine-tuning dials, UHF tuner dials, mechanical slider cable boxes with no remote, block converters that barely worked and God knows what other hassles… the introduction of the truly cable ready tuner in TVs and VCRs was an absolute godsend!
In the next installment we will see how the introduction of digital cable messed things up for those of us who really love our cable ready devices.