That should be a Logic Trunked Radio model #8610. 800mhz band 35w LTR only -- no talk around 10 systems, 10 groups. Pretty well worthless for ham use. Requires a trunked system to talk through.
good luck
n5ztl

I found that connecting pin 10 (ignition sense) to pin 12 (general i/o) that there was enough voltage to stay powered up on my units. To get the internal speaker to work required a jumper from pin 16 to pin 13. Probably want to make sure pin 13 isn't connected to ground or some silly thing that will ...

You might check which revision rss you are using. I am new to the GTX 900, but did have an 800mhz that had been programmed with revision 4 software that I corrupted the codeplug with an early version software. Lab software was able to blank the board and load a different image, but it is major grief ...

Most ham antennas specify gain over 1/4 wave dipole, most commercial antennas specify gain over 1/2 wave dipole. Difference of 3db comparing 1/2 wave to 1/4 wave. Therefore ham 9 dbd (1/4wave) = commercial 6 dbd (1/2 wave). I would recommend grounded (top) antenna configuration if it is much taller ...