RD150YB

RD150YB transmitting triode (in a very temporary support!) which measures about 1.1m high. The anode alone is 61cm x 20cm. It is a directly heated triode capable of 150kW anode dissipation.

Filament voltage	31.5 - 34V
Filament current	440 - 470A
Anode voltage	20kV dc max
Total emission	100A
Anode current	20A max
Continuous anode dissipation	150kW max
µ	40 - 48
Impedance	800 - 1200 ohms
Grid current	4.5A max
Grid power	8kW max
Frequency	30MHz max
Inter electrode capacitances
Grid to filament	101pF
Anode to filament	6pF
Anode to grid	51pF

Cooling required 150 litres of water per minute minimum at 1.5kg/sq cm pressure, and the filament terminals and glass envelope require 6 cubic metres/minute forced air at a pressure of 160mm of water

The weight is 33.5kg (it feels much heavier!).

These devices spend their lives vertical - the grid and filament assembly is very long and suspended only from the top, hanging down into the anode.

The RD150YB is equivalent to the CAT17C, broadly similar in specification to the Marconi CAT17, which was used in the Marconi SWB18 shortwave transmitter.

The crate measures 4'8" x 2' x 2' and is very well made; the valve was suspended inside secured on a ring and bolted to the crossed metal framework at the base. The top section of the crate lifts off and there is a door built into the lower part to enable the bolt to be removed.

View of the glass section of the valve, also showing three air-blast rings to cool the top and bottom of the grid seal, plus the anode seal. The grid connection is between the top two air-blast rings. The copper ring at the top is another air blast, to cool the top of the envelope. The feed for this is next to one of the filament connections right at the top.

View of the filament leads just above the upper grid seal.

Here you can see the anode, the flange that forms the seal at the top of the water jacket, supports for the lifting handles, and the glass-to-anode seal and its air-blast ring.

A view of the grid connections (outer) and filament connections descending into the anode.

Here is the valve suspended in its crate.

Thanks to Frank Philipse for providing data on this valve.

This file was last modified 13:36:15, Thursday September 28, 2006