>> Along this line, and at the risk of perhaps being slightly OT, if anyone >> knows why television uses channels while radio uses frequencies (for the >> most part, that is, the 88 channel) FM Marine Band in the 156 MHz range >> being an exception), I would be interested in hearing about it. > There's no intrinsic reason for using one form of naming over another. > However, note that _if_ you assign "channel numbers" to specific > frequency allocations, you are *permanently* fixing the utilization of > that chunk of RF spectrum. e.g. in going from 15khz deviation to 5khz > deviation on FM, you'd have to either completely 're-number' > everything, or you have non- consecutive "channel numbers" as you go > up the band. > When you (the regulatory authority) "haven't decided" what the minimum > allowable spacing between frequency assignments is, or even _if_ the > spacing between assignments will always be a multiple of that minimum > -- it is *really* difficult to come up with a channel 'number'. > [TELECOM Digest Editor's Note: This is an example of how someone > screwed up when the Citizens Band radio channels were numbered. CB is > allocated the space between 26.965 kc and (originally) 27.255 kc. The > 'channels' were 10 kc apart, and there were (originally) 23 channels. > (Well, not originally, when there were 8 channels, but in later > years.) If you look at the difference between 27.255 and 26.965 as > divided in 10 kc increments you get more than 23. That's because the > FCC took three spaces in the middle and reserved them for use on > garage door openers. So we had channel 22 as 27.225 and channel 23 > a full 30 kc later, on 27.255. Then the FCC said they would expand the > CB area all the way up to 27.405, or 40 channels, although common > sense would imply actually 43 channels if you take 27.405 minus 26.965 > at 10 kc increments. What the FCC did, in an effort to 'tidy up' that > discrepany was run the channels slightly out of order. After channel > 22 (27.225) they created channel _24_ at 27.235, channel _25_ at 27.245, > then they had the (already existing) channel _23_ at 27.255 where it > had always been, and then by 10 kc up to channel 40 at 27.405. Having > those two channels out of order in the frequency allocations did make > for some tricky programming of the 'gang switches' (revolving knobs > which select the channels). PAT]
LOL - and then there were those who had the Siltronics sets. They used to be on 27.415 or Channel 41 as we called it. This was in the days before I got my amateur license.