COLLINS 208U-3

GENERAL DESCRIPTION


photo Collins 208U-3 208U-3 3 KW HF POWER AMPLIFIER

Features Applications The 208U-3 is an automatically tuned linear power amplifier with 3 kw PEP output over the 2-30 mc frequency range.
When used with an external exciter, such as the Collins 310V-1, and an antenna, it provides a complete HF transmitting system. Input power required is only 0.2 watt at the operating frequency.
Emission capability includes single sideband, CW or FSK signals. Several types of antennas can be accommodated. The 208U-3 operates from a 200-250 v, 47-420 cps, 3 phase primary power source.
Control functions are actuated by low voltage, direct current circuits. Dial-pulse control equipment is optionally available for remote operation over ordinary wire lines.

APPLICATION VERSATILITY

The 208U-3 is part of the Collins Universal Radio Group equipment and is ideally suited for fixed station, transportable or shipboard applications.
It is mounted in a rugged Unistrut frame to which doors, trim panels and meter-control panel may be added as required for custom configurations. Cabinet trim panels are available to completely enclose the power amplifier, to enclose the front, top and back or to enclose the front only, depending on installation requirements.
Installation is simplified since the RF and power supply units can be separated to permit passage through restricted space and then be reassembled.

CIRCUIT FEATURES

A rapid, highly accurate automatic antenna tuning system requires only the RF signal from the associated exciter for frequency information Shielded ceramic tetrode tubes contribute to excellent circuit stability and provide high gain with a minimum number of stages and tuned circuits. Fast operating, automatic tuning insures optimum linearity and peak power output at all frequencies. An efficient antenna network matches a wide range of antenna impedances.
Power supplies have automatic line voltage regulation. Long life silicon rectifiers with transient suppression are used in all power supply circuits.
Reliability is assured by the use of solid state components in all applicable circuits. All significant voltage, current and RF power levels are monitored by three meters. Voltage samples are readily available for external logging and optional fault alarm equipment.

Collins 208U-3 diagram
TECHNICAL SPECIFICATIONS
Frequency Range 2-30 mc.
Power Output 3 kw PEP or average.
Drive Power 0.2 watt PEP.
Output Impedance 50 ohms. Will accomodate up to 3:1 SWR. Will match at 32 ft. whip accessory items.
Output Intermodulation Distortion Third and higher order products at least 40 db below either of two equal test tones which drive the power amplifier to rated output.
Output Harmonic Content All harmonic output is not less than 80 db below the fundamental power output measured on a 50 ohm load at any level up to rated power output.
Tuning Time Maximum, 10 seconds; nominal, 5 seconds. Tune failure informtion is provided if equipment should fail to tune within 15 seconds.
Power Source 200-250 v, line to line, 3 phase, 47-420cps. A primary power regulator automatically maintains the input voltage at 225 v.
Power Consumption Single tone CW at rated power, 7.5 kva. Two-tone at rated power, 4.3 kva. Power facdtor not less than 0.9.
Ambient Humidity 0%-95%.
Altitude 0-10,000 ft. operating; 0-50,000 ft. nonoperating.
Vibration 5-15 cps 0.03" double amplitude; 16-55 cps 0.02" double amplitude or 1 g, whichever is less.
Shock Each individual unit (RF and power supply subunits), when mounted in a suitable test frame, shall be capable of accepting 3 blows each direction in each of three planes for a total of 18 blows and each impact shall be 15 g maximum, 11 milliseconds in duration.
Size 31 9/16" W, 69" H, 22 ⅜" D (80.17 cm W, 175.26 cm H, 56.83 cm D).
Weight Approx. 750 lbs. (340.2 kg).
Specifications may change without notice

TUBE COMPLEMENT
RF stages AF stages and modulator
Number Type Number Type
1 4CX3000A

2 4CX350A



THIS TYPE OF TRANSMITTER IS INSTALLED IN THE FOLLOWING COUNTRIES

ITU Country
ITU Country