> There are apparently few people who understand the significance of RF
> current. Consider the number of ham radio amps that do not cool the tank
> circuit. In commercial amps, it is common to put cooling water through
> the hollow copper tubing used in the main L.
>
I have several tank coils in my junque box scrounged from industrial RF
generators
with the brass water-line fittings attached to each end of the coil. I have not
decided
whether to make watts or whiskey!
Henry comes up occasionally with some great inovations. On the 8-K Ultra,
the cooling air comes up from the pressurized chassis through the socket
and a ring of holes drilled around it. The chimney over the 3CX3000A7,
instead of extending down to the top surface of the chassis only extends
down to the bottom of the cooling fin assy. of the tube. This allows cooling
air to flow over ALL components in the RF deck; ( both upper and lower)
before passing through the tube cooling fins and exiting the top of the
chimney that is secured to the solid lid of the RF deck. IOW, the entire RF
deck is pressurized. A generous blower can be utilized with this scheme
because the 8-K is a remote-controlled amp and can be located away from
the ham shack. I have ordered one of these chimneys from RadioDan to
replace the metal chimney on my converted Henry 2000D amp. This will
get rid of about 10pf of stray C in the anode circuit making the tank Q a
lot lower on 10m; but I digress.
(((73)))
Phil, K5PC
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