Figured the first step towards choosing a group ride channel would be knowing the frequencies that are used by both GMRS and FRS systems, and mapping out the shared frequencies between the two bands.
It's easy enough to find the frequencies allocated to the FRS and GMRS bands, but a lot harder to find any data from the manufacturers of the communication systems which frequency they broadcast on for which channel. The FRS band is a 1, 2, 3, etc layout, which is adopted by all the FRS radio manufacturers ASFAIK. But GMRS doesn't follow any such guidelines as it was established for commercial use, with options such as repeater systems and more tunable radios. The motorcycle GMRS radio interfaces seem to fall somewhere in the middle between the ease of use of an FRS-like channel selector, but with the commercial broadcast ranges and frequencies.
I dug around online and couldn't find any data that mapped out the Chatterbox GMRS X1 channels to the actual frequencies they use. The X1 only displays a channel number ::13 for instance:: but doesn't indicate what it mhz it is broadcasting on.
And the Chatterbox website sucks. Flash over substance. Literally. There's so little real feature data, and technical inof on the site, it's bizarre. It feels more like they're in the business of selling MP3 players than communicators.
The only way I was able to correlate the channel to mhz was to set-up a programmed scanner to each of the GMRS steps and then click the X1's PTT mike on each channel, while scrolling through the programmed frequencies, to see if I was getting a signal. It took a while to go through the channels and test them, but below is the X1's channel/mhz mapping.
I confirmed that the X1 does indeed use the first 7 FRS channels. I then discovered that the X1 channels 8 -15 then hop around the various designated GMRS frequencies, with no real logic to my eyes, aside from 25 hz steps. Feel free to steer me in the right direction, if you understand why the channels were mapped this way. I love learning new shit.
I don't know if any of the other GMRS two-way communicators document what frequency their channels broadcast on. It would be great to see if they all use the same channel mapping convention below, and if not, to document the differences.
Anyone with a "non Chatterbox" GMRS care to add to the list below?
EDIT::
1- "Kenwood 3101 Freetalk" uses same GMRS channel #1 - 15 mapping as CHBX X1
2- "Motorola Talkabout Distance" uses same GMRS channel #1 - 10 mapping as CHBX X1
BAND______________FREQUENCY__________COMMUNICATOR CHANNEL
GMRS........................462.5500................CHBX GMRS X1 11
GMRS | FRS 1............462.5625 ................CHBX GMRS X1 1
GMRS........................462.5750................CHBX GMRS X1 8
GMRS | FRS 2............462.5875 ................CHBX GMRS X1 2
GMRS........................462.6000 ................CHBX GMRS X1 12
GMRS | FRS 3............462.6125 ................CHBX GMRS X1 3
GMRS........................462.6250 ................CHBX GMRS X1 9
GMRS | FRS 4............462.6375 ................CHBX GMRS X1 4
GMRS........................462.6500 ................CHBX GMRS X1 13
GMRS | FRS 5............462.6625 ................CHBX GMRS X1 5
GMRS........................462.6750 ................CHBX GMRS X1 10 :: emergency frequency
GMRS | FRS 6............462.6875 ................CHBX GMRS X1 6
GMRS........................462.7000 ................CHBX GMRS X1 14
GMRS | FRS 7............462.7125 ................CHBX GMRS X1 7
GMRS........................462.7250 ................CHBX GMRS X1 15
FRS 8........................467.5625
FRS 9........................467.5875
FRS 10......................467.6125
FRS 11......................467.6375
FRS 12......................467.6625
FRS 13......................467.6875
FRS 14......................467.7125
It would make sense to use a FRS a frequency for group rides with riders using a variety of equipment on both bands, but if a ride had just GMRS communicators, it would make sense to choose a GMRS-specifc frequency to avoid picking up signals from the general FRS users ( hikers, mountain bikers, kids in a shopping mall, etc...)
It doesn't seem to make sense to select "talk groups" in any of the frequency or band choices. These are arbitrary tone settings that don't seem to correlate from one manfacturer's systems to another. They would work just fine if everyone were riding with an X1, but mix in other two way communicators and you'd miss out on connecting.
Hope this conversation keeps going. I'd really love input on other manufacturer's GMRS channel mapping.
Other threads discussing frequencies for BARF events and rides::
Laguna Seca thread::2-11 discussion
Query about group ride channel
Cheers,
Cooper