When I converted my SB-200 to a single-band 160m amp, I followed the
directions (more or less) at
http://pa0fri.home.xs4all.nl/Lineairs/SB200/sb200eng.htm#DESIGN . The
toroid was a single T-200-2 core with between 11t and 14t of #14 stranded
PTFE insulated wire, IIRC. The details are on that site. I got almost 800w
out on 160 CW.
I also used a large (>1600 pf) external variable loading cap to the output
with a UHF tee connector and a short length of RG-58C/U.
Some photos except for the toroid (on the bottom) and the added plate choke
are here:
http://www.w0btu.com/files/misc/SB-200/ . The extra filament choke and the
PA0FRI input mods are clearly visible in the first photo.
While you're at it, add the fuse and series 10 ohm 10w resistor to the HV
line. I used an ordinary 250 volt AGC 1 amp fuse. When I first replaced the
tubes, it blew a couple of times with nothing more than a silent blue flash.
73, Mike
www.w0btu.com
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|