I've use the Larson NMO 27 along with a PCTEL on a Diamond trunk mount and ended up abandoning them. I'm aware that center of mass is the best, but trying this just because. I traveled the same route every day and using either one, I was unable to make my usual contacts. I could hear 'em but was talking to myself. We've all been there and there could be the worst weather in the world, and we're all out there determined to rectify that situation! (Honey, can you hold the umbrella?) So of course this led to mobile antenna testing day, again.
My setup was a small sedan, truck lid, body, frame all bonded. Rig 35 as the analyzer. Power output 3 watts. All in the 11 meter band.
Stationary, Tx location mid mountain top, mid afternoon, with a station to my NE 14 miles away, LOS, a station to the S 11 miles bouncing off a couple of ridges, no line of sight, and one NW 8 miles with a mountain directly in the way.
Now being data driven and trying to eliminate bias, the 3 stations were blind to what I was using. The candidates were:
Larson NMO 27,
PCTEL,
Hustler SC,
Stryker SR2K 10",
Wilson 2000 10" shaft.
I had to modify a Diamond mount to accept a 3/8 x 24 stud for the Hustler, Stryker and Wilson where the mount was next to the NMO mount. Same length of coax for each mount, same side of the vehicle, and each antenna was pre-tuned before hand and rechecked once installed at the "testing site" (just needed to sound official). Everything was under 1.5.
Station #1 #2 #3 ( in S units)
Larson 2 2 nada
PCTEL 2 2 nada
Hustler 6 6 3
Stryker 6 6 3
Wilson 6 6 3
These are all relative and not exact measurements. Those operators are all radio heads but I'm unaware if their Rx is calibrated to specs but it still gave me some on air data. Each antenna was tested 3X in a random order and averaged up to the next highest whole number. I would have went with more testing, but who got board, who had to go eat, who had to go to the bathroom, etc, etc. It was a couple of hours worth of work but worth it for me.
Now for my bias. I don't care for base loaded or mag mount. And I just can't come to drilling a hole. Now I'm running a fender mount with a Hustler or a 4' glass and sometimes a Sirio 5000 mounted on it. Bottom line for me, height makes might but I know that 71 incher is gonna break that mount. Also, lowest SWR were the NMO mounts and so is my dummy load. Also I was always a function above form guy, but the Hustler matches the color of the car and looks like it was made for it.
