Drake - L4-B - Amplifier
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Equipment:
L4-B
Date:
1975
Category:
Group:
Sub Group:
Linear Amplifier
Information
The R L Drake Model L-4B Linear Amplifier offers continuous
2000 watts PEP-SSB, 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
realteration of the input circuit.
The L-4B uses two 3-500Z or two 8802/3-500Z 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 AGC 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.
2 Manuals
Service and user manual
Manual type:
Service and user manual
Pages:
26
Size:
2.6 MB
Language:
english
Revision:
Manual-ID:
Date:
Quality:
Scanned document, reading partly badly, partly not readable.
Upload date:
Aug. 9, 2017
MD5:
32e70232-91c2-2655-dbcf-8f208ad73598
Downloads:
1005
Information
STANDARD WARRANTY (inside front cover)- 1
GENERAL SPECIFICATIONS...
FRONT PANEL CONTROLS...-...1
DESCRIPTION...
INSTALLATION INSTRUCTIONS-...3
A. Unpacking---------------——-------3
B. Tube & Chimney-——---------------3
C. Location--------------——---------4
D. Power Requirements—-------------— 4
E. Jumper Connection Diagrams—-------4
F. Low Pass Filter--------------------5
G Antenna Requirements---------------5
H. Ground Requirements----------------5
I. Exciter Requirements—-------------6
J. Transmitting AGC———-—--—- 6
K. VOX Relay...6
L. Initial Connection Diagrams-----— 7
M. Viewing Angle Options--------------8
TUNING PROCEDURE...9
A. CW & RTTY...-...9
B. SSB & AM---------------------------10
OPERATION------------------------------11
A. CW & RTTY...11
B. SSB-----------------------------—11
C. AM...U
D. SWR Calculation—----———------—12
E. Accessory Frequencies--------------13
THEORY OF OPERATION--------------------13
SERVICE DATA-...—...—14
A Amplifier —-—-—--—-----14
B Power Supply —------——16
C. Ordering Service Parts-------------17
D* Returning L-4B to Factory—---------17
ALIGNMENT------------------------------18
A. Input Coil Adjustment--------------18
B. Meter Adjustment————————18
C. Knob Pointer Alignment——---—--19
D. Wattmeter Calibration-————19
SCHEMATICS for L-4B Amplifier and Power Supply (last 2 fold
out pages)
Service and user manual
Manual type:
Service and user manual
Pages:
40
Size:
4.4 MB
Language:
english
Revision:
Manual-ID:
Date:
September 1975
Quality:
Scanned document, all readable.
Upload date:
March 26, 2025
MD5:
3d293e95-f81d-7e4e-7744-a9b671251fd0
Downloads:
26