Note
QST, Apr 1962, p. 129.
Note: In Eugene Rippen's book, "Tube Type Transmitters" (second edition), the REL L-103 is incorrectly attributed to Reeves Electronic Laboratories.
The L-103 (also designated as the RELiant L-103) is a table-top, 1,000-watt grounded-grid linear amplifier manufactured by Radio Engineering Laboratories, Inc. (REL), Farmingdale Division. Designed as a companion unit to the RELiant S-119 SSB Communication System, it can also be used with other exciters capable of meeting its drive requirements.
Features multi-meters monitoring plate and screen currents. Because screen current peaks at exact plate current dip (resonance), operators can easily achieve precise tuning—even under heavy loading conditions where plate current dip is minimal.
Built-in Reflectometer: A power monitor circuit provides a selectable forward or reflected RF power reading across the entire 3.4–30 MHz spectrum without requiring band adjustments.
Hi-Low Power Pass-Through: Allows switching between low-power exciter operation (direct to antenna) and full high-power amplification without disconnecting cables.
Specifications
– Frequency Range: Continuous coverage from 3.4 MHz to 30 MHz across all amateur/HF bands.
– Operating Modes: SSB, CW, AM, FM, and FSK.
– Power Ratings:
SSB: Up to 2000 W PEP input (2-tone).
CW, FM, & FSK: 1000 W input.
AM: 750 W input.
– Output Tank: A variable Pi-Network designed to match 52-ohm unbalanced coax loads (with up to a 2:1 SWR).
– Drive Requirements: 40 W PEP (2-tone SSB) or 20 W average (CW) at a 52-ohm input impedance.
Power Source: Operating power is supplied by an external companion power supply unit (P-110), while internal bias circuitry is self-contained within the L-103 cabinet.
Tube Lineup (3 total)
(2) 4CX300A RF amplifiers
6FG6/EM84 tuning indicator
