17-11-2012, 02:18 PM
Hi Al, yes, more or less my conclusions plus a more constant selectivity across the band, Hans Vogt showed his iron core products (carbonyl iron I think) at the Berlin radio show in 1932, this would tally up with Garys (radio fixer) discovery of a pot core in one of the IFs in a French radio dated 1935, Vogt seemed to hold several patents at different stages, although Iron cores had been developed prior to his development, they were limited to LF use, mainly as reactors to compensate for capacity loss in telephone circuits ie: to cancel out Xc. If Vogt had not come up with his development then know doubt somebody else would have, but so far to date as far as web searching goes he appears to be the farther of the low loss HF iron dust core, during that time radio transmission was really on the increase, the bands getting crowded, so better selectivity in receivers was beckoning.
Interestingly the parts list in the Barlow Wadley receiver has the name Vogt along side the parts reference for the permeability core in that receiver.
Lawrence.
Interestingly the parts list in the Barlow Wadley receiver has the name Vogt along side the parts reference for the permeability core in that receiver.
Lawrence.
