Why are cable TV channels out of order after channel 13?

[KE7IZL]

I was looking at Pan-American television frequencies - Wikipedia and Pan-American television frequencies - Wikipedia and I noticed that only channels 2 through 13 are the same with both cable and over-the-air TV. While with over the air, higher channel numbers are always at higher frequencies, with cable TV, Starting at channel 14, it goes back and uses some lower frequencies between below channel 7. And then at channel 23, it goes back above channel 13 again. The channels then again increase with the frequency, until channel 95. For some reason channels 95 through 99 are back down again between channels 6 and 14. And then the remaining channels from 100 and higher are all placed after channel 94, and continue to increase the channel number along with frequency. The result is that only TV channels 2 through 13 have the same frequency in both cable and over-the-air TV systems.

I realize that there are gaps in the channel frequencies with over-the-air TV to make room for other services (such as FM broadcast band), that can be filled when using cable TV (as FM broadcast is only over-the-air), but why so drastically rearange all the TV channels to fill those gaps? Why not just add any new channel number to fill those gaps? Like why not keep all the same frequencies as used with over-the-air TV, up to channel 83 (the highest frequency OTH TV channel), and then starting with channel 84 start filling in the gaps at lower frequencies for cable TV?

 

[wtp]

lower frequencies travel better through the cable.
less attenuation means more signal.
and there are even lower channels that fill in gaps in the TV bands
so instead of trying to match the channels up in the 800 band, they are shifted lower and fill the gaps.
i found a chart where the 120 to 174 has 8 channels in it. so 14 to 22 are in there.
so it is done so you get more signal.

 

[mmckenna]

That and there is some historical reasons:

Older cable TV systems were often based off a "Community Antenna" system. Often it was a company that had a good high site and would pull in TV stations from areas that would not normally be received by roof top or set top antennas. The "community antenna" system would just take the off the air stuff, amplify it, and distribute it.
Often, FM broadcast stations were carried over the system.
Side bar:

I used to work at a college TV station that ran over the local cable network. We had our signal going out to the head end, and would receive a cable TV feed back for monitoring our channel. We distributed that feed through the station, and I had an old stereo receiver in my shop. I could pull FM broadcast stations that I couldn't pick up with a regular antenna.​

Anyway, the original systems were just off the air channels. Then they figured out they could add more channels from distant locations. Those were added in at channel slots unused by the local stations. And that kept growing, more channels became available, and more space was needed.
Also, the older TV's and cable TV systems only ran on the "off the air" channels, and were not "cable TV ready.
At one point, some systems had to have a set top box that would contain the tuner that would work with all the non-standard channels used by the cable TV system, and convert them to Channel 3 (or 4) for the TV sets that were not "cable ready".

Back when I was a kid, the local cable TV system had a lot of channels available, but the coax distribution system couldn't carry them all. Back then, the amplifiers could only handle so much bandwidth. The solution was that each house had two cable TV drops, and everyone had an A/B selector switch sitting on top of the TV set. So, not only did you have to choose the channel you wanted, you had to know if it was on the A side or B side.

As technology progressed, they were able to pack more and more channels into the system. Locally, the old A/B system went away. They just kept packing more channels into the system wherever they could. The technology on the amplifiers and the rest of the system were upgraded to handle more channels.