GMRS & off-road comms lab
Independent research and rule-checked tools for GMRS radios, antennas and trail comms. Every frequency and power limit here is checked against 47 CFR Part 95 and linked to the rule.
Free tools
Two tools that answer the questions most new GMRS users ask first, with the rules linked on the page.
Lab board
We publish our methods before the first result. Each slot stays empty until we’ve bought the radio and run the course.
miles
Same two points each time: a forest trail, a canyon, and a suburban grid. We check whether a message gets through, then read back five standard phrases at each marker.
“Up to 35 miles” on the box assumes mountaintop to mountaintop. You need a number for your terrain.
Read the protocolW
Conducted power into a calibrated attenuator and wattmeter on every channel group, with a full battery and a low battery.
Rated power and delivered power differ, and the rules cap some channels at 5 W or 0.5 W ERP.
Read the protocolµV (12 dB SINAD)
Signal generator into the antenna port, stepped down until audio hits 12 dB SINAD.
Hearing weak stations matters as much as transmit power.
Read the protocolSWR
Vector network analyzer sweep from 462 to 468 MHz, on the vehicle and on a ground plane.
A mistuned mobile antenna wastes power on exactly the repeater inputs you need.
Read the protocoldB(A) @ 1 m
A-weighted level at 1 m from a standard tone at full volume, plus clarity notes taken in a moving vehicle.
In a rig on washboard road, loud and clear beats every other spec.
Read the protocolBrowse
Licensing, channels, power limits and call signs, straight from 47 CFR Part 95.
ExploreHandhelds, mobiles and base radios: power, receivers and what’s actually certified.
ExploreMobile and base antennas, gain, SWR and mounting.
ExploreRig installs, trail channel plans and convoy comms.
ExploreFamily comms plans, repeaters and power for when the grid is down.
ExploreOur fixed-course range protocol. Results appear only when we’ve actually run it.
Explore