Codan made very heavy duty HF mobile antennas used by for example the Australian police. The antenna is a typical tuned whip design like the “screwdriver” designs pioneered by amateur radio designers long before the Codan antennas appeared on the market. They use a end fed method with autotransformers in a switched configuration. There are two combinations that switch in a step up, step down or a paralell combination of autotransformeres. There is also a nice motor break function that shorts one of the spetter motor windings to ground.It looks like there is a scan function where the antenna switches in a broadband amplifier. The antenna is very narrowband due to the tuning and high Q so a wideband amplifier may be needed so the radio can determine what HF channels are open without tuning mechanically.
