Sub channels are a "continuous tone coded squelch system", ctcss. Sometimes called "sub audible tones" because that is what they are. Sub channel is a very misleading name that, is used because us radio users aint smart enough to get our pea-brain around the whole idea. When your garmin displays "ch 1 sub 1, what it is really showing is, rf freq 462.5625 mega hertz, audio freq 62.7 hertz.
Changing the tone does not change the rf freq. It only changes the audio tone which controls the squelch.... It controls what your tranciever will receive on a given freq. Part of the problem is that, garmin, bca, motorola, chatterbox, ect do not number thier tones the same. Channel 3 and tone 6 may or may not be the same on different radios. All the channel numbers will be the same freq, it is just the tones or as you know them, sub channels that may not match. When finding a channel to use with a mix of different radios, you will have better luck by turning the tone system off (sub channel 0). Get everybody able to talk to everyone else. Then try to find a tone.
There is a very good article on wikipedia explaining this system. All radio users will do themselves a favor by reading it and understanding the system....
https://en.m.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
Changing the tone does not change the rf freq. It only changes the audio tone which controls the squelch.... It controls what your tranciever will receive on a given freq. Part of the problem is that, garmin, bca, motorola, chatterbox, ect do not number thier tones the same. Channel 3 and tone 6 may or may not be the same on different radios. All the channel numbers will be the same freq, it is just the tones or as you know them, sub channels that may not match. When finding a channel to use with a mix of different radios, you will have better luck by turning the tone system off (sub channel 0). Get everybody able to talk to everyone else. Then try to find a tone.
There is a very good article on wikipedia explaining this system. All radio users will do themselves a favor by reading it and understanding the system....
https://en.m.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
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