So, 61 years ago, started a story in Electronics Weekly’s edition of December 21st 1960.
The story continues:
The Hughes 307 H operates in the frequency range 8.5-9.5 kMc/s and has an average power output rating of 500 W.
The high power is claimed to be due to a folded waveguide slow wave structure coupled with periodic magnetic focussing.
Integral ion pumps and metal/ceramic construction bring the weight to 21 pounds, including the magnets.
Saturation gain is 54 dB and the maximum duty cycle is 1 per cent.
A second X-band TWT, the 308 H, with a lower output of 15 kW is also announced by Hughes.
Intended. for the range 8.6-9.9 kMc/s it has a saturation gain of 53 dB.
On/off modulation of the beam is effected by grid control which has an effective mu of 55.
Pulse rise times of from 10-50 millimicroseconds are claimed to be possible with this tube.
The slow wave structure is similar to that of the 307 H, with permanent magnetic focussing.
The total weight is 14 pounds.