With any modern bipolar transistor output based ham radio you won't get the DC ground buss off the AC safety buss.
The emitter of the transistors is bonded to the heat sink, which in most radios is bonded to or an integral part of, the chassis.
As such, as soon as you hook the radio up, the negative lead of the power supply and whatever 'ground system' you have on the chassis of your radios is now bonded together.
Via the emitter junctions of the output transistors. What's sad is, most CB radios don't suffer from this as they are designed for positive and negative ground. If your ham radio doesn't EXPLICITLY state it's for positive ground and negative ground use, you can make a damn safe bet that the chassis is at DC ground potential.
--Shane
WP2ASS / ex KD6VXI