CV1571 pulsed radar transmitting triode
The VT58 (E960, CV1058) and VT58A (CV1571) are similar and were based on the ACT10 transmitter valve and designed as a replacement for the NT57 silica valve. It could operate efficiently up to 200MHz and was used in the Chain Home Low radar transmitter. A pair of VT58 valves could generate 30kW peak in 3µs pulses at 1000 pps., which was 1.5 times the output of NT57s in the same equipment.
The difference between the VT58A and the VT58 is in the ageing process - a report in AVIA 7/917 (UK National Archives) makes reference to this and that the VT58A reaches 31kV, whereas the VT58 is 27kV. The process took 15 minutes per valve as opposed to 5 minutes for the VT58.
After a year it was fitted with a thoriated tungsten filament, to become the VT98.
The number P9418C-11 is stamped onto the dome on the end of the anode.
The valve was capable of operating at 100MHz, and with suitable precautions at up to 250MHz. It required forced-air cooling at 90 cu.ft./min with a pressure drop across the valve equal to 2" of water.
Above: CV1571; below: VT58A
This file was last modified
11:17:58, Thursday April 14, 2022