Hi Stephen,
The TK-760G driver is in charge for this particular radio and others, and in my research (yes, I'm the author of it) I found all this variants of the Kenwood TK-860G:
- TK-860G-K (400, 440) # 400-430Mhz original
- TK-860G-K1 (450, 490)
- TK-860G-K2 (485, 512)
- TK-860G-M (400, 440) # 400-430Mhz original
- TK-860G-M1 (450, 490)
- TK-860G-M2 (485, 520)
The K/K1/K2/M/M1/M2 are designations from the service manuals and contrasted against the original KPG software by me, this marking may be omitted/overlooked at all in the OEM software and even may not be explicitly expressed on the radio body, YMMV.
As you can see in the simple "TK-860G" brand there are six different variants covering a wide chunk of the 70 cm band, some are close enough to work and I have tested it with two models at my disposal here, the K & M models are good up to 445 Mhz on RX (the OEM states up to 430, but they get unstable on TX beyond 440.5 or so)
The Chirp's driver try to hide this complexity to the users by looking for the low level ID's and selecting the correct freq range from this list. In the attached image you can see that in the Settings > Dealer Settings you can find the limits of your radio.
Of course there are always room for improvement, the K1 & M1 can be pulled down into the ham bands but as I can not test this I prefer to disable this option to get the radio in a working state (Which it seems to be your case/need), the same with the M & K models that I have tested stable up to 440.
Please do test TX on you case with the OEM Software, just because the radio can RX well into the ham bands it doesn't means that the TX will be fine also, I have got this kind of troubles here.
If you like sent me a Chirp's image of your radio (click on my name on the post to know my email) I can work with you and make more tests about the stability of this radios and maybe widening the ranges if the radios behave stable enough in the ham band.
Aka: we can test the lower safe limits for your model to patch the driver with it; I wait for your email.
73 Pavel CO7WT
