Homebrew tetrode RF deck FS
Ku7i at WORLDNET.ATT.NET
Sat Mar 25 01:09:52 EST 2000
This RF deck uses a 4CX1500B and comes with a spare 4CX1000A. Built by a
retired EE here in San Diego. I am only selling the RF deck (fully
operational), the 4CX1500B (full output), spare 4cx1000A (full output) and
the screen supply which has taps for 150, 250 or 350 vdc. You supply your
own high voltage supply. With 3500vdc (3100 under load) this amp running the
4CX1500B will do 1500 out with 40 watts of drive with zero grid current.
Covers 160 to 10 but on 10 the bandswitch arcs pretty bad so I only use it
on 160 to 15. Uses a pair of UCXF 700 vacuum variables in the output tank
(700pF at 10kV). Beutiful turns counters on the two vacuum variables. The
coils is a fixed tapped design (Johnson 232 series) and uses a rugged
bandswitch. Homebrew plate choke. SK-800B socket and chimney. Dayton 4C004A
blower. Tube is in a pressurized compartment. This amp is really built well
and very easily does the legal limit. Typical values are 40 watts of drive,
1500 watts out, plate current of 840mA, plate voltage of 3100 volts, zero
grid current, 350 volts on the screen, and less than 10mA screen current.
Sorry, no pictures available.
The deck is built onto a sub-chassis that is about 4 inches deep by 17" wide
by about 15" deep. The front panel is a 19 inch panel with rack mount screws
and fits into the same size BUD cabinet as the 75A4. You supply the cabinet.
Screen supply mounts externally. Connections on the rear of the deck are for
RF in and out, T/R relay, multi-pin connector for various power supply
voltages (screen, B-, 120 vac to rf deck, etc.) and ALC.
There are several partial schematics but not one totally complete scat. Lots
of various handwritten design notes and circuits so the end-product is a
combination of these. You will need to draw the schematic from reverse if
you want to figure out exactly how this deck is wired. He did a professional
job on the wiring and it looks great.
Prefer pick up so I can op test the amp for you. Price is $575 shipped
48. Remember, you supply the high voltage supply and cabinet for the RF
deck. Will professionally double box the amp and tubes and ship seperately
via UPS ground.
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