by Norm Wilson N6JV – Visit the museum at N6JV.com
HY31Z – HY1231Z
In the early 1920’s, the Hytron Corporation in Salem, Massachusetts, began making vacuum tubes under their division Hytronic Laboratories. I have seen little evidence of production until the middle 1930’s when they came out with a new, expanded line of high frequency transmitting tubes. They had a lot of competition so they needed to offer special features.
The HY31Z incorporated many of these features. The base was made of low loss ceramic for VHF operation. The HY31Z was rated to 60 MHz at full power. HYTRON tubes were only rated at CCS (Continuous Commercial Service). The plates are made from graphite that won’t sag under overload. They are zero bias and are designed to be easy to drive. A tube with 2 sections can have the plates tied together or operated as a push pull or push push multiplier. Push pull triplers were the common circuit to get drive on 10 or 5 meters. The HY31Z operated with 6.3 volts on the filament, but you could order an HY1231Z which ran on 12 volts perhaps in a mobile application.
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