Codan HF Radios are High frequency radios that are used by the Royal Flying Doctor Service, Mining Companies, Police, Fire Services, etc. They are useful in that they allow you to talk over many miles where UHF is basically line of sight.
For example if I was on the Nullabor Plain somewhere and came across an accident, I would be put through to Perth or Port Augusta Flying Doctor service who would be able to obtain details from me and respond accordingly.
The units themselves generally come with what is referred to as Autotune antennas or in my case a multi tap antenna, you see a lot of four wheel drives with these types of radios fitted.
You are correct in assuming that you could link into the fuse box for accesories but most accessories do not draw the type of power that these radios do, you also need an in line fuse, coz these radios cost a pretty packet to buy let alone repair. The multi tap antenna alone will set you back anywhere from $300:00 to $500:00.
Check out www.codan.com.au
for more details about HF radios.