An interesting old Coil

[pwdrive]

Peto Scott did a lot of kit components etc in the early days, have trawled the web for Copex, not a lot that I can find, according to your measurements the two high value inductors are more or less the same value, maybe another take on it could be dual tuning (switchable stations) singly a 500 pf variable would appear to tune to what is I presume metres engraved on the top (1,000-2,000...150Khz to300 Khz) it would do the low end of that band more or less spot on at maximum capacitance, the high end would need some extra capacitance than you would normally expect a 500 pf variable to have when fully unmeshed, maybe that extra capacitance is accounted for in the other windings plus antenna capacitance/valve input capacitance etc.

All guess work at the moment from me.

I searched the online Wireless World archives, Copex came up zilch for early stuff, quite a few for Peto Scott but not what we are looking for so far as I can see, radiomuseum have a Copex coil listed, I think it was prefixed SG (usually means Screen Grid as in "TheScreen Grid Three" etc) there's a reference to a Copex SG coil in Google books, it could have been a Wireless World extract (can't remember) I think it was a sales listing from some component supplier, all it gave was the coil and it's price, can't find anything yet as to who Copex were or where they operated from.

Lawrence.