DRAKE L-4B - Description

ME'lERS - Plate Current, Grid Current/Plate Voltage/Forward Power/Reflected
Power (switch selected>.
POWER SUPPLY controls - Two circuit breaker reset buttons.
DESCRIPl'ION
The R L DRAKE Model L-4B Linear Amplifier offers continuous 2000 watts PEP-
ssa, and 1000 watt DC. CW, AM and RTTY operation covering the ham bands 80
through 10 meters. All frequencies 3.5 to 30 MHz may be covered with some re-
alteration of the input circUit.
The L-4B uses two 3-S00Z or two 8802/3-S00Z or two 8163 or two 3-400Z zero bias
triodes in a Class B grounded grid circuit configuration that utilizes RF negative
feedback for lower odd order distortion products.
A transmitting AGe circuit controls the exciter gain to allow the highest average
power without peak clipping. An internal changeover relay feeds the antenna
through when the L-4B is turned off. A pair of relay contacts bias the output tubes
to cutoff, eliminating unwanted heat and diode noise when receiving.
The output tubes are forced-air cooled by a. very quiet low velocity, high volume
internal blower. Two taut-band suspension meters indicate plate current, grid
current, plate voltage, and relative RF output power.
The separate solid state power supply requires no warm up period and provides
excellent dynamic and static voltage regulation.
. Do not turn on the L-4
amplifier with the top cover
removed because the high
voltage interlock shorts out
the 8 + and will damage
power supply components.
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