Drake L4-B Amplifier
Manufacturer:
Model:
L4-B
Date:
Category:
Group:
Description:
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.

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Service and User Manual
Manual type:
Service and User Manual
Pages:
26
Size:
2.56 Mbytes (2688945 Bytes)
Language:
english
Revision:
Manual ID:
Date:
Quality:
Scanned document, reading partly badly, partly not readable.
Upload date:
2017 08 09
MD5:
32e7023291c22655dbcf8f208ad73598
Downloads:
951

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 ... —--19 D. Wattmeter Calibration-————19 SCHEMATICS for L-4B Amplifier and Power Supply (last 2 fold out pages)

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