automatic and semi-automatic aerials

My 328 has had an aftermarket electric aerial fitted, of the automatic type which raises when the radio is switched on and lowers when it is switched off. To achieve this the console switch has been bypassed. I have reversed this, but now the aerial does not work because the original required a semi-automatic aerial. There is a fix detailed elsewehere here using diodes that will replicate the required operation with an automatic aerial but I am wondering if an automatic aerial is simply a semi-automatic with a relay inside it. If so it might be possible to modify the automatic and make it semi-automatic. If anybody has any experience of these aerials and knows if this is possible, I would welcome some insight.

GG

 

Thanks, yelcab. I guess the answer is to dissemble and experiment. I saw a wiring diagram for Harada automatic antenna and it looked as if it ought to be straightforward. A bit of guidence would help, however so I'll see if Steve Magnussen responds.