JM Oganis

The model 422B CENTURION uses the classic pair of 3-500Z tubes. The RF deck and power supply are combined into a single, attractively styled, black desk top cabinet. The power output is rated at 1300 watts on SSB and CW and 650 watts using “key-down” modes. Drive required for full power SSB operation is 100 watts. The CENTURION operates on all bands (including WARC) from 1.8 to 21.5 MHz. 21.5 to 29.7 MHz is enabled with user installation of an expansion board, supplied at no charge upon proof of licensed authority.

Tuned input circuitry assures low input SWR for modern solid state transceivers. The power supply features a tape wound Hypersil transformer for minimum weight and size. Careful engineering of power supply assures that the Centurion is run within the 3-500Z manufacturer’s recommended specifications for the tubes. Competitors amplifiers often run the 3-500Z tubes at 1500 watts output, above the recommended tube specs. This decreases expected overall tube life and increases the potential for tube failure.

QSK operation is a standard feature, not an option, for the CENTURION. QSK CW is achieved using reed relay input, Potter-Brumfield mechanical relay output. This system has proved to be more reliable over time than vacuum relays or PIN diode switching, and makes very little audible noise from relay clatter. This QSK system also makes the CENTURION ideal for fast switching digital modes. SSB VOX operation is silky smooth and virtually noiseless. This versatile control system assures compatibility with all exciters with amplifier control provisions.

A tube-axial fan is used for forced air cooling. Air flow is routed through the power supply as well as the upper and lower sections of the RF compartment. Air inlets and outlets are on the sides and top of the cabinet to optimize low pressure, low noise air movement.

Left meter on the front panel is a dedicated meter for plate current, the right meter is a multi-meter for plate voltage, grid current, forward or reflected power. A full time 10 element LED bargraph continuously monitors peak power output.

Specifications.

• Band Coverage: 1.8-2.0, 3.2-4.7, 6.5-10.3, 13.4-19.6, 17.6-21.5 MHz. 21.5-29.7 MHz after authorized modification.
• Input Power: 2000 watts, maximum.
• Power Output: 1300 watts SSB/CW. RTTY and SSTV 650 watts, 50% duty cycle. Drive power 100 watts for full rated output.
• Efficiency: 50-65%, depending on frequency and load impedance.
• Input/Output lmpedances: 50 ohms, unbalanced. SWR <2:1.
• Distortion: -35 dB from 1 kW RF output level.
• Harmonics: -50 dB typical.
• CW Break-In: QSK capable. Relay switching.
• Tube Compliment: Two graphite anode 3-500Z.
• Power Amplifier Circuit: Class AB2, grounded grid.
• Plate Voltage: 3100 volts, no load. 2600 volts, full load.
• Cooling: Forced air with full chassis air flow.
• Metering: Dedicated plate current meter. Selectable multi-meter for plate voltage, grid current, forward or reflected power. Ten element LED bargraph display for peak power indication.
• Front Panel Status Indicators: Standby, operate, transmit.
• Primary Power: 220-250 Vac @ 15 A.