(Long )

Quote:
Mine have 18 channels and 38 sub channels that is over 600 different frequencies I doubt there will be 600 different user groups


Just to clear up a little misconception (and interject some good old technical gobledy-gook), the 38 sub-channels (also called "privacy codes") are not different frequencies nor do they ensure privacy. What they are are CTSS (Continuous Tone Squelch System) settings. CTSS works by utilizing a sub-aduible tone (too low for normal human hearing) that is processed by radio to "open up" the squelch system on the radio. Thus your radio will remain quiet until someone on your frequency using the CTSS code you selected transmitts. In practice it works like this:

Say your family goes to the airshow. You take you GRMS (or FRS) radios. You set the channel on 7 and the code to 26. You hand one to the kids and send them off exploring. Now half of the people there have done the same thing and 2 other families have selected channel 7. One has selected code 10 and the other has selected no code. Despite the number of radios being used, yours remains quiet until Junior calls in to ask about lunch. You then hear the other families discussing their lunch plans. What happend? When your squelch was opened by the CTSS tone transmitted by Junior's radio, it will allow _all_ of the signals being transmitted on that channel to be heard (or monitored). Most GRMS/FRS radios have a monitor button that overrides the CTSS system so that you can listen for any signals on a channel.

Some more tidbits:
- The 18 channel radio shown on the other post is a GRMS/FRS radio - 14 channels are FRS frequencies (GRMS shares 7 frequencies with FRS).

- In the U.S. GRMS radios require FCC licensure. The license costs about $75 dollars, is good for 5 years, covers almost your entire extended family and requires no testing (just $ and info).

- Canada has approved FRS radio for general unlicensed use (I don't know about GRMS). U.S. C.B. and (properly licensed) Ham radios are also legal in Canada. (Ham radio is permitted in most countries and licensed operators can easily obtain permits operate in other countries.)

- Check out the FCC Website for more information on U.S. radio regulations.

- Check out the ARRL Website for more information about Amateur (ham) radio in the U.S.

Radiate Safely,

73's

JimJr (KC5JIW)