GMRS for Motorsport

amaff · 2025-07-23T03:13:58Z

I know there's at least a couple others here running GMRS radios in race / track cars. Whatcha running?

Up until now I've been making do with a handheld based system in my car (with an external antenna). Nerdie racing car harness with Fuze molded ear plugs / buds, and a KG905-G on the door bar, but I've never been thrilled with it. It's performed fine (100% coverage at most tracks I run, 80%+ at worst), but it's something extra to manage and care for and the only decent mount I could find for it had it rotating around to where the screen wasn't visible (did I just bump the channel knob? uh oh...) and if I was lucky I would just be able to reach the volume knob to adjust it while belted in the car w/ a helmet and HANS. Always had to make sure it was turned off for the night, always had to make sure the battery was charged.

Before:

So I wanted a mobile radio solution. But most mobile radios obviously won't work with a K1 connector based car / headset harness. Cut to learning this weekend about the BTech UV25X2. Compact 20W radio, but has an adapter with a K1 connector to plug a headset in. It is technically a ham radio (actually, I don't know how they get away with it, the thing near as I can tell is WIDE OPEN, not just restricted to 2m / 70cm ham bands), so, caveat emptor and all that, know what you're doing when you're messing with it because it definitely WILL let you do things you maybe shouldn't be.

Changed the power connector on the back over to a more weather resistant 2-pin deutsch connector. No I'm not using the cigarette socket in the car, this was just for testing on my desk. In the car it's wired to a switched bus-bar and battery ground in the car.

Integrated the mounting bracket with my switch panel with a pair of rivnuts:

I don't plan on running it at full power most of the time, but I tested with it to make sure everything works. Good SWR, and higher than the advertised 20W. (1.12 SWR @ 8.6W on Low power).

I need to finish cleaning up the wiring and zip tying / wire-wrapping everything, but it's in and I got to test it out simplex with my son on an H/T, and also to a handful of local repeaters, both with the handset it comes with, and with the full helmet & earbuds setup. Seems to work great, good signal reports all round, we'll see how it holds up

nokones · 2025-07-23T13:43:03Z

I had a leather case speciality made by Leathersmith and I bolted the case on top of the switch panel. You might be able to see it if you expand on the attached picture of the inside.

Depending on where I was racing, I used either VHF of UHF in the Astro 25 Digital mode with an XTS portable. I used a Racing Electronics Harness with a PT-T on the steering wheel and Racing Electronics Helmet Kit with their custom molded ear inserts. Since, the body panels were composite I ran with a non-groundplane Antenex NMO mount antenna on the roof. I never had any coverage problems and my crew were using the Otto Behind-the-head headsets with the remote antenna attached to the headset and a XTS portable.

I thought about going with a mobile, but I never saw the need.

Although, I have been a GMRS licensees since the mid-90s, I never used any GMRS freqs. I used Part 90 freqs I was licensed for in both the VHF and UHF bands.