CV253 'crystal valve' (semiconductor!)
This is a matched crystal valve for use in pre-plumbed mixers. It was designed to enable changing the crystal valve without the need to adjust the matching elements in the waveguide assembly. The frequency range is 6GHz to 12GHz, and it is designed to work in climatic temperatures of -40C to +100C. The CV253 was a CV111 selected for high sensitivity.
The foil wrapping is designed to protect it from damage caused by RF fields.
Crystal valves were used in the mixers of radar receivers and were susceptible to burn-out caused by the high RF power of the transmitted pulse. It was for this reason that TR Cells were so vital in single-aerial operation, and also the reason for the development of thermionic diode mixers such as the CV58 and CV258.
(Note: Yes I know it is a semiconductor, but as these crystal valves were so vital to radar and many of my other unusual valves are for radar too, surely this deserves to be an 'honorary valve'!)
This file was last modified
17:07:36, Sunday February 26, 2017