A handheld GMRS radio sitting on a kitchen counter is not a base station, it’s just a handheld indoors, and it performs like one. A real GMRS base station is a small, worthwhile project that dramatically improves your ability to reach family members out running errands, kids at practice, or a repeater across town.
The core components
- A mobile GMRS radio (not a handheld) capable of full legal power, typically 25 to 50 watts depending on the model
- A 12V power supply sized for the radio’s peak current draw, not just its average
- A dedicated base or mast-mounted UHF antenna, not a compromise indoor antenna
- Quality coax sized appropriately for the run length to keep loss manageable at UHF frequencies
Where to put the antenna
Height matters more than almost anything else here, which I cover in more depth in GMRS Antennas: What Actually Improves Your Range. An attic-mounted antenna is a reasonable compromise if you can’t put something on the roof or a mast, though metal roofing and HVAC ductwork can attenuate the signal more than people expect. A short mast on the side of the house, above the roofline, is usually the best balance of performance and simplicity for a home base.
Once the antenna is outside and up high, ground the mast and put a coax surge arrestor where the cable enters the house, bonded to the same ground as your electrical service. The National Electrical Code (Article 810) covers how antenna masts and lead-ins should be grounded, and a local electrician can confirm it is done right. It will not make a direct lightning strike harmless, but it gives nearby surges and static buildup a path to ground that is not through your radio.
Power supply sizing
A 50 watt mobile GMRS radio can pull well over 10 amps on transmit. Undersized power supplies will sag under load, causing distorted audio or the radio resetting mid-transmission. Size your supply for the radio’s rated peak current, not the average draw, and leave headroom. If you’re already running a ham shack, an Astron-style linear supply or a quality switching supply both work fine for GMRS as well.
Programming for your household
Program in your family’s agreed-upon simplex channel for direct talk, plus any local repeaters worth having on tap. Label channels clearly on the radio’s display so anyone in the family, licensed or not, can grab the mic and use it correctly without a tutorial.
If this is part of a bigger station buildout rather than a standalone GMRS project, my Building Your First Ham Radio Station pillar page walks through the same power, antenna, and layout decisions from the ham radio side.