Thanks Jim that all makes sense to me, will give it a go as I have
several 4-400s.
Mike
VK2AMF.
At 02:18 PM 8/04/2023, you wrote:
toggle quoted message
Show quoted text
It's done all the time.?
DON'T strap the grids together.? That's? BBI video
fubar.?? Run a separate strap from each grid pin to
chassis.? 6 x straps in total.?? Drill 6 x holes in
chassis, if needed.
Don't bond the grid pins to the aluminum standoffs that are used to sub
mount the white Johnson style sockets either.?? You will end up
with an int every time.?
?
Cut off bias is the same, just use a 3 watt mof resistor in the CT, like
anything from 10k to 100k.?? Shunted out on TX via relay
contacts.?? Diss in that resistor is almost zero watts on
RX..and is zero watts on? TX.??
Depending on B+ used, operating bias is way less vs a 3-500Z.??
Either no bias, or just 2-3 volts.? Use a few 1N5408 diodes in
series for bias.?? 100 ma of idle current is ample for any
3-500Z / 3-400Z / 4-400 A / B / C
You will get a little less PO with the 4-400's.? They need a bit
more drive vs the triodes.
Jim?? VE7RF
Mike Fleetwood
Canberra Australia and Sidcup UK.
Worldwide email address
is:?????
mfleetwood@...
