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My 500 khz TX is made out of recycled components
from the junk box.
1940 xtal in osc
IC osc chip/IC divider chip/IC driver chip/FET PA
class E, then on the drain side
1940's ceramic inductor (tinned copper
wire) out of a TU5B tuning unit, 1950's tube TV line output core,
rewound for impedence matching FET/50 ohms.
LPF using unmarked cores similar to
FT200 type.
FET out of an old marine tx 1960's vintage.
CCT board for chips reworked from an old pre used
board.
Ferrite chokes in V + line from old
smpu, decoupling capacitors and misc items, small heatsink and fan from junk
box.
Psu for chips 12 regulated, ex surplus
Psu for FET rebuilt using ex surplus high capacity
capacitors, not regulated
The finished package looks neat and tidy and is
totally reliable, and no SMOKE
The secret to avoid smoke in class
E is to get the FET drain matching network spot on to avoid
voltage/current spikes during switching. If designed properly you will be
in the ball park and just need minor adjustments ie adjusting coil
tappings while making observations on a 'scope.
I used components that I had lying around in junk
boxes and the cost was NIL.
This is the TX that I used on 500 khz to work VE1ZZ
and RW3ADB on normal CW.
73 De Mal/G3KEV
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