|[AMRadio] Millen Coil info|
knjhanlon at msn.com
Tue Jan 12 12:50:07 EST 2010
Congrats on finding some nice pieces of Millen gear. You might enjoy visiting the James Millen Society web page at http://www.isquare.com/millen/millen-page.htm<http://www.isquare.com/millen/millen-page.htm> . You would also be welcome to join the group.
You could certainly use standard B&W Junior (75 watt) coils for the 90800 exciter, but you'll need to make new jack bars for them. I have used a bar made from "Plexaglass" or whatever we are calling it these days. I've used banana plugs with the leaves stripped off leaving just the center pin for jack bar pins. The same size coil is used in both the 6L6 plate and the 807 plate position.
All of the coils are 1.5 inches inside diameter.
The 80 meter coil, Millen number 43082, is 2 inches long and has 40 turns. It has a 7 turn link on the "B+ end" of the coil.
The 40 meter coil, Millen number 43042, is 2 inches long and has 22 turns. It has an 8 turn link.
The 20 meter coil, Millen number 43022, is 1.5 inches long and has 9 turns. It has a 2 turn link.
The 40 meter 6L6 cathode coil is wound on a 1 inch diameter form, is 3/4 inches long, and has 8 turns.
I don't have a Millen 80 meter cathode coil, but I made my own from a pice of B&W Miniductor. It is about 3/4 inches in diameter, 1/2 inch long, and has 16 turns.
If you have a grid dip meter, you can check the resonance points for the cathode coils as plugged in to the transmitter. The 80 meter coil should resonate between 80 and 40 meters, around 5 mc would be good. The 40 meter coil should resonate between 40 and 20 meters, around 10 mc would be good.
I use a series string of five 9-volt transistor radio batteries for the required 45 volt bias.
I'm not lucky enough to have a 90881 amp, but I will copy this message to the James Millen Society reflector. Perhaps one of the JMS guys will be able to give you coil information for the amp and for the 90800 exciter on 10 meters.
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This page last updated 16 Jan 2018.