[Amps] Drake L4B to 6 Meters Help

[Paul Baldock]

I have converted an SB220 and a TL922 for 6M. Both will produce 1300W PEP 6M.
( FYI I have converted an SB200 and that gave 600W PEP)

A stock L4-B will easily produce 1KW PEP on 10m and should do the same on 6M.

Note:
You need to ground the grids directly.
You should use a PI (not T) on the input with the PI output cap right 
next to the cathode. I use compression trimmers.
You should reduce the turns on the plate choke and cathode choke to 
about 1/3 of what they were originally.
You should use an L-PI on the output. The L is necessary to overcome 
the output cap of the tubes. I used the original TUNE cap with most 
of the plates removed, and a new LOAD cap.
The open frame antenna relay should work fine. You will need to add a 
little cap, maybe around 10pF, on the normally closed path to 
compensate for the relay inductance when the amp is bypassed.

- Paul  KW7Y