Permeability Tuning

[Yorkie]

Oddly, the Fenman I doesn't (on VHF), but the Fenman II and the HFT111 do. I don't know about the HFT113 but I think it does.
Was it down to economics or performance? It can't be size 'cause there's plenty of room in the Fenman I.

Alan

The Feman 1 does in fact use permeability tuining on VHF - leastways, the one that I restored does. It wouldn't tune, and the reason was that the cam which causes the cores to move in and out of the coils was seized. I'm not at home just now, but when I get a few mins over the next few days, I'll take a pic of the tuning arrangement as the chassis is out of the cabinet. Quite a neat bit of electro-mechaical engineering. Permeability tuning was used extensively on push-button car radios. The buttons weren't so much 'switches' as 'levers', which pushed the cores in or out of the coils by a pre-set amount chosen by the owner to tune to the desired stations. Primitive by current standards, but effective nevertheless.