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Type 803 (= Raytheon Type RK28A) is an HF pentode transmitting valve rated for use up to 20 MHz and provided with an external g3 pin so that suppressor modulation can be used if desired. This military transmitting valve is marked US Navy and has a date stamp of March 31st 1942. It is rated for 1000 hours service.

The anode is 1 mm thick and is a casting designed to dissipate 125 Watts. The anode connects to the top cap and the ceramic insulators are indicative of a high anode voltage. The internal structure is obscured by a very close wound wire grid.

The operating data is given for Class C operation. The control grid current can rise to 10 mA. The voltage on g3 is 45 Volts.

The valve is somewhat too powerful for airborne (or amateur) use but would be very suitable for a ground-based or small-ship transmitter intended for communication with friendly military aircraft.

The substantial wide glass tube envelope is 58 mm in diameter and, excluding the special five pin base pins, is 216 mm tall.

References: Data-sheet. Type 803 was first introduced in 1937. See also 1937 adverts.

Pin Connections

Absolute Maximum Operating Conditions^¶

Thanks to Frank Philipse for supplying the above PDF datasheet.