Tio Pedro wrote:
The National polystrene coils were becoming scarce by the time
the last HBR ran in QST. Bill (exray) uses Garolite XXX tubing
(phenolic) for his plug in coils; a bit pricy for my tastes. Ted's
coils had Qs of around 150 or so.


I remember Allied radio and Lafayette radio both carrying those
polystyrene coil forms as late as the early 70's (The last HBR article
was in '64 IIRC). Those coil forms were NOT made by National Radio, the
National coil forms were made of dark brown plastic (bakelite?) or
ceramic material. Millen also made some plug in coils that were made of
an orange colored bakelite like material. The '67 HB had a novice
transmitter (1625 final) that used those coil forms, Allied Radio part
numbers given.

I had a few of those coil forms at one time purchased to build a one
tube regenerative receiver from the 'boy electrician' book by Alfred
Morgan. Barry electronics had the 1H4G tubes for 50 cents back then.

Ocean State Electronics was carrying the polystyrene coil forms a few
years ago. They also had some 'cloned' forms that would fit the old
National Radio SW3 receiver (same weird 6 pin base).