Batboard

Hi,
I have an old GM300 UHF model M44GMC09C1 403 - 430 Mhz, I wish to program out of band 385/395 Mhz, holding the shift key allows me to program frequencies up to 600 MHz (Obviously the radio would not work there) but will not allow me to program just below the specified range.
I know how to use HW to mod the checksum in mdf file to add ch's but am stuck programming lower down.
Any help advice, please
Thanks

Look here: http://www.batlabs.com/gm300.html

Check the section titled "Out of Band by Modifying the .MDF File".

Thanks Al, much appreciated

The GM300's in the 450-470 UHF range will not work below about 438.

In addition to the article for the UHF modification the VHF frequency list have the bandsplit identifier 0300.
The limits are set to 146 MHZ = B4 05 to 174 MHZ = CC 06.
Change the B4 05 to A0 05 is for start at 144 MHZ.
For correct checksum 5D53 change in the copyright text 3x space (20hex) to 4 (34hex). So now you can enter lower VHF Freq.