they are NOT trunked. they are MURS/BizBand radios. unlicensed. i believe they're maxons.
dog wouldn't be able to afford a trunking lease, or would he be able to afford encryption. also, if he had a trunked lease, they wouldn't work on the other islands in hawaii, nor would they work on the mainland (where they've done a few bounties)
dog doesn't have a FCC license, nor does Da Kine bail bonds, (his company).
his radios only work a short distance. you'll notice on some bounties, usually when his team is far away he uses the nextel. when he's right down the street, he uses the radios. you'll also notice that sometimes when you hear the radio in use, you'll hear static/interference when they're at longer distances (a good example of this is when they went to a football stadium to get a fugitive, and leland, who was inside the stadiums parking lot sounded quite staticy on dog's radio- well out of the way, outside the parking lot.
If he had another type of radio, they would be licensed under "Duane chapman, Dog Chapman, D. Chapman or Da Kine Bail Bonds".
Duane also refuses to nor can he carry a firearm. He's stated on many occasions that he think guns are nothing but trouble.