Why Are Frequencies Out Of Order?

Why are the some of the Channelised Frequencies in the Frequency Lists out of sequence? The attached image is the one kindly supplied by DelBoy but its the same on other lists and corresponds to the radio.

Hi Mark,

The history of CB radio is still right there with our radios today.
 

In 1958 the FCC (Federal Communications Commission) initially gave 23 channels for use by the American public which also included allocations for radio control devices. This explains the gaps between 3 & 4, 7 & 8, etc. and the space between 22 & 23 which were also for the latter usage.

When they expanded the CB channels to 40 they simply filled in the gaps above 23.

The gaps were often known as 'Alpha' channels because CB'ers would alter their radios to transmit in those gaps.....much to the annoyance of the radio control fraternity!

The original US frequencies allocated are marked in your list as 'Band D', 26.965 to 27.405 MHz.
Often CB'ers would "expand" their radios either by swapping crystals, simple PLL (Phase Locked Loop) programming or other means to give 'higher' and 'lower' frequencies and hence the mirroring of the frequency hops.

When 'legal' CB came to the UK shores in 1981 (UK27/81) the government didn't want modified radios and also had a fruitless business plan in mind so allocated continuously stepped frequencies with a weird offset.


Some countries had/still has a different set of CB frequencies and channels from the list you've included above.


Worth noting, (old man Ham radio moustachio miserable git syndrome), that only the Band D and UK40 have ever been officially sanctioned in the UK with SSB/AM use on the Band D area now known as EU frequencies. (At least legally over here.)

Bit of a mess isn't it? But it's all fun.  


All the best,
Victor

yes it's a strange one, do you remember in the  seventies when cb became popular rigs like the presidents were on a different channel to everyone else, you used to get a list of what channel they were on and everyone else 

Hi Victor,

Thanks for that. Now you mention it I do recall there being 23 channel radios about when CB was around in the 70's. Had I remembered that I would have probably put two and two together and come up with 4.325 

My first radio had 23 channels.
I can see the radio now but can't remember the make.
Second radio was a Sharp small window wow 40 channels and then i got the big window.
Funny i can remember that stuff but can't remember what i did last week lol.
Thinking thinking was there a General electronics 23 channel ??????? splinters in my fingers now from scratching my head too early yet.