[gary rabbitt]

I was thinking that too. But with the superhetrodyne scheme and using an IF/osc circuits, that idea kind of didn't make sense. Oh well.

[morzh]

Well, the antena tank is tuned, then the mixer acts as simple amp and so the dial is kept to, then the problem with the TRF concept is IF is not tuned to that same frequency.
It is possible capaciive parasitics in the IF filter bypass it and then you get some reception.