Some time back I had posted my experience with four different antennas from an intentionally marginal location which was several miles from the home base and hundreds of feet lower in elevation, using Midland MXT400's at each end (running at mid power setting) and and with a GP-9 2m/440 ham antenna at 40 feet on our ridge top farm base location. The GP-9 is not optimum for GMRS due to being quite a bit off the design frequency and has nearly 2:1 SWR on the 467 channels but reasonable SWR on the 462 channels helped by the coax loss of course. Results surprised me somewhat:
- 2m/440 ham antenna retuned for GMRS generally showed one bar on transmit and receive - 6" Midland stock mag mount quarter wave showed two bars and much better signal copy - so called 3 dB Midland NMO antenna showed three bars - so called 6 dB Midland NMO antenna showed four bars
I read that at least one person had problems with the 6 dB antenna melting the center coil, but so far we have not had that happen with only limited transmission time when mobile.
We use Midland magnetic NMO mounts on our vehicles. My wife has the MXT115 with the 3 dB antenna on top of her Equinox SUV and I have the MXT400 with the 6 dB antenna on my Malibu rear trunk lid so that we can clear the garage door. Range between vehicles is several miles and not that much different than when we used simplex on 2 meters when we use ham equipment.
