Q: What is FRS?

A: FRS stands for Family Radio Service and is a low-power 22 channel two-way radio service in the UHF 462/467 MHz range. Shares same frequencies with GMRS.

Q: What is GMRS?

A: GMRS stands for General Mobile Radio Service, and is a medium-power 22 + 8 (repeater) channel two-way radio service in the UHF 462/467 MHz range. Shares same frequencies with FRS.

Q: Is CAVERN Channel 8 or 9, 15, 23 or what?

A: All of the above! CAVERN is heard on 462.550 MHz which is GMRS/FRS Channel 15, however different radios access this channel via different channel locations. CAVERN-programmed RETEVIS RT22 hear.

Q: How do I monitor for emergencies only?

Q: How do I alert people to an emergency?

Q: What constitutes a local emergency?

Q: Does CAVERN own these channels?

Q: Why can’t people hear me?

Useful Links (WIP)


CalFire Incidents: fire.ca.gov/incidents/

GMRS /FRS / Radio



CobbWeb.org (under construction, needs volunteers!)


Sonoma County Emergency: SoCoEmergency.org

CAVERN project (Firewise) Groups

CAVERN Channels

CAVERN’s preprogrammed Retevis RT 22 radios channels match the way most FRS/GMRS radios are programmed, but only for the first few channels. This is because the RT22 only has 16 channels and cannot transmit at the legally required 0.5 Watts for FRS channels 8-14 (so we left those out for now).

What this means in practical terms is that on CAVERN pre–programmed FRS radios (e.g. the “Retevis RT22”), Channels 1-7 correspond to most off-the-shelf FRS radios, HOWEVER: CAVERN’s Channels 8-16 are NOT programmed to the standard frequencies and tones.

This table below shows: pre-programmed CAVERN channel locations (in the first column); the corresponding normal “Standard” FRS and GMRS channel location for most non-CAVERN radios (i.e. the “factory settings”) and; additional CAVERN frequency & tone settings for radios (i.e. to help limit Main Repeater access to Cobb Area volunteers):

CAVERN ChStandard ChFreq/Tone (Info)
1Ch 1(Group 1 Boggs)
2Ch 2(Group 2 Cobb)
3Ch 3(Group 3 BottleRock)
4Ch 4(Group 4 Hobergs)
5Ch 5(Group 5 Seigler)
6Ch 6(Group 6 Hannah)
7Ch 7TBD (not used by CAVERN)
8Ch 15462.550 Megahertz
+ DCS: D071N
(CAVERN Repeater
/ Daily Talk
& Weekly Check-Ins)
9Ch 15462.550 Megahertz
+ CTCSS: 103.5 hertz (aka “tone #13”)
(CAVERN Emergency Alerts/Tests ONLY)
10-16Ch 16-22TBD (not used by CAVERN)