About San Geronimo Police Frequencies
- 1 conventional channel is analog FM, so any scanner can receive it. Enter the frequency and set the tone shown in the table.
- 5 conventional channels use a digital mode (P25), which needs a scanner that decodes that mode.
- Trunked radio systems that carry law-enforcement traffic here: Marin Emergency Radio Authority (MERA) P25 (Project 25): 29 talkgroups. A trunking scanner is required, and it must support the system type shown.
- To follow a trunked system, program a control channel first. For San Geronimo, start with the East Simulcast Cell site of Marin Emergency Radio Authority (MERA) P25, about 7 miles away. Its control channels: 769.85625, 771.21875, 771.74375 MHz.
- 2 listed entries are marked encrypted. No scanner can decode encrypted audio.
Marin County channels that also cover San Geronimo
Tactical
| Agency | Description | Frequency (MHz) | Tone | Mode | FCC |
|---|---|---|---|---|---|
| MERA Conventional | Law Enforcement Car-to-Car | 485.0875 | NAC 293 | P25 | WQNS265 |
| MERA Conventional | Law Enforcement Car-to-Car | 491.0625 | NAC 293 | P25 | WQNS265 |
| MERA Conventional | Law Enforcement Car-to-Car B | 769.3063 | NAC 411 | P25 | WRAR816 |
| MERA Conventional | Law Enforcement Car-to-Car A | 771.2938 | NAC 411 | P25 | WRAR816 |
Talk-around & Car-to-Car
| Agency | Description | Frequency (MHz) | Tone | Mode | FCC |
|---|---|---|---|---|---|
| Marin County Sheriff | Sheriff Low Band | 39.2400 | 82.5 PL | FM | KMA224 |
Jails & Corrections
| Agency | Description | Frequency (MHz) | Tone | Mode | FCC |
|---|---|---|---|---|---|
| MERA Conventional | Marin County Jail Conventional Backup | 856.6125 In 811.6125 | NAC 293 | P25 | WRCA288 |
Marin Emergency Radio Authority (MERA) P25
Project 25
| Agency | Description | Talkgroup | Hex | Mode |
|---|---|---|---|---|
| Central Marin Police | Central Marin Police Department Dispatch | 15324 | 3bdc | T |
| Marin County Parks and Open Space | Open Space District Dispatch | 15600 | 3cf0 | T |
| Marin County Sheriff | Marin County Sheriff's Office Dispatch | 15400 | 3c28 | T |
| Marin Municipal Water District | Marin Municipal Water District Rangers | 15135 | 3b1f | T |
| Southern Marin Police | Southern Marin Police Department Dispatch | 15360 | 3c00 | T |
| Central Marin Police | Central Marin Police Department Tactical | 15325 | 3bdd | T |
| Central Marin Police | Central Marin Police Department Tactical | 15326 | 3bde | T |
| Law Enforcement Mutual Aid | Blue | 15301 | 3bc5 | T |
| Law Enforcement Mutual Aid | Blue | 15302 | 3bc6 | T |
| Law Enforcement Mutual Aid | Blue | 15303 | 3bc7 | T |
| Law Enforcement Mutual Aid | Blue | 15304 | 3bc8 | T |
| Law Enforcement Mutual Aid | Blue | 15305 | 3bc9 | T |
| Marin County Parks and Open Space | Open Space Tactical | 15601 | 3cf1 | T |
| Marin County Parks and Open Space | Open Space Tactical | 15602 | 3cf2 | T |
| Marin County Probation | Probation | 15436 | 3c4c | T |
| Marin County Sheriff | Marin County Sheriff's Office Tactical | 15401 | 3c29 | T |
| Marin County Sheriff | Marin County Sheriff's Office Tactical | 15402 | 3c2a | T |
| Marin County Sheriff | Search and Rescue Tactical | 15411 | 3c33 | T |
| Marin County Sheriff | Search and Rescue Tactical | 15412 | 3c34 | T |
| Marin County Sheriff | Search and Rescue Tactical | 15413 | 3c35 | T |
| Marin County Sheriff | Court Security | 15423 | 3c3f | T |
| Marin Municipal Water District | Marin Municipal Water District Tactical | 15136 | 3b20 | T |
| Southern Marin Police | Southern Marin Police Department Tactical | 15361 | 3c01 | T |
| Southern Marin Police | Southern Marin Police Department Tactical | 15362 | 3c02 | T |
| Marin County Probation | Juvenile Hall | 15439 | 3c4f | T |
| Marin County Sheriff | County Jail | 15417 | 3c39 | T |
| Marin County Sheriff | County Jail | 15418 | 3c3a | T |
2 encrypted talkgroups (cannot be monitored)
| Agency | Description | Talkgroup | Hex | Mode |
|---|---|---|---|---|
| Marin County Sheriff | Task Force Tactical | 15431 | 3c47 | T Encrypted |
| Marin County Sheriff | Task Force Tactical | 15432 | 3c48 | T Encrypted |
Nearest trunked radio sites
Distances are measured from the center of San Geronimo.
East Simulcast Cell · Marin Emergency Radio Authority (MERA) P25
Project 25 · RFSS 1 · Site 1 (hex 1) · NAC 4F1 · about 7 mi away
Control 769.85625, 771.21875, 771.74375, 774.44375
Voice 770.59375, 771.44375, 771.89375, 772.19375, 772.34375, 772.64375, 772.79375, 773.21875, 773.89375
Mt. Tamalpais · California Radio Interoperable System (CRIS)
RFSS 1 · Site 17 (hex 11) · NAC 9DA · about 7 mi away
Control 769.20625, 770.90625, 773.31875, 774.06875
Voice 774.54375, 774.84375
West Simulcast Cell · Marin Emergency Radio Authority (MERA) P25
Project 25 · RFSS 1 · Site 2 (hex 2) · NAC 4F2 · about 7 mi away
Control 770.04375, 771.59375, 774.16875, 774.91875
Voice 769.79375, 770.51875, 771.06875, 772.04375, 772.49375, 772.94375
What do these numbers mean?
- Control channel
- The frequency your scanner listens to first. It tells the scanner where each voice call is happening, so program it before anything else.
- Voice
- The other frequencies the site uses for calls. A trunking scanner follows them automatically once it has the control channel.
- Site
- One tower location of the system. Scanners show the number in decimal or hex, so both are listed.
- RFSS (Radio Frequency Sub-System)
- A group of sites run by the same controller. Large Project 25 systems can have several.
- NAC (Network Access Code)
- A hex code the site transmits. Your scanner can use it to ignore other systems on the same frequency.
- Talkgroup
- A virtual channel on a trunked system, such as one agency’s dispatch. Programming uses the decimal or hex number, depending on your scanner.