Johnson Desk Kilowatt

[k5ygc]

Anyone familiar with this exciter input mod on L-100 and L101? Looks like they added 3 turns of ins. wire on L-100 and a 100 pf 1.5kv mica to gnd. and 2000 pf 1.5kv to gnd on L-101.

[W9BHI]

What you got there is a later model unit.
The earlier model had only two primary links.
Your schematic is for an earlier unit.
I have owned both types and the later one like you have will show a better but not great input match to 50 ohms.
The Thunderbolt amp had the exact same input circuits for early and later models.
Don W9BHI

[k5ygc]

What you got there is a later model unit.
The earlier model had only two primary links.
Your schematic is for an earlier unit.
I have owned both types and the later one like you have will show a better but not great input match to 50 ohms.
The Thunderbolt amp had the exact same input circuits for early and later models.
Don W9BHI

Thanks Dons for the help. I thought that was what it was for but was surprised to not see it on the schematic. 73 Mark K5YGC

[W3GMS]

Mine was modified to include the 3rd link as well.  In reality, driving the JDK with a tube rig which has a pi-network, its really not an issue.  Just apply enough drive to get the proper grid drive and enjoy the rig.

Joe-W3GMS