Yeah I gotta agree with tagada, ringing a t2 radar is definitely efficient, so at least a 2 click command for it is almost certainly useful and quite unlikely to use by accident.
Imo a 1 click command would be fine too, cause when do you ever assist a non-upgrading radar unintentionally?
Edit: I'm wrong actually.
Ringing a t2 radar with t1 pgens only gives you an additional 38 energy in adjacency bonus, i.e. 9.5 additional energy per t1 pgen.
That is slightly less efficient energy per mass than a t2 pgen is:
t1 pgens around a t2 radar:
(20e+9.5e)/75m = 0.39e/m
t2 pgen, no adjacency:
500e/1200m = 0.42e/m
By the same logic as for the t3 fabs, I'd say wheelie is right and we want the command only for ringing omnis.