[Milsurplus] VHF radar

[William Donzelli]

> One was an incident mentioned here about some new carrier just back to 
> Norfolk from sea trials in '46.  The only radar that worked in the 
> fog-bank was a "old bedspring set" that had been retrofitted.   
> The captain dressed down the tech staff for their negligence - 
> unaware of water droplet effects on microwaves.

The U.S. Navy was procuring VHF sets well into the 1950s.
 
> Hey the poor SCR268 was missed last week.  Our 1st radar, the "searchlight 
> aiming set."

I missed that on purpose, as the gun laying/GCI/fire control radar guys 
*did* benefit greatly from the Tizzard mission. The SCR-268 was a decent 
radar for its time, but that time slipped away very quickly with the new 
microwave sets. A few fell into Japanese hands fairly intact as well. The 
SCR-268 has the distinction (disgrace?) of being one of the few bits of 
militaria that was being surplussed out *before* VJ day.

> Sometime soon thereafter the TR switch was born.  In fact, the biggest
> surprise, supposedly, at German disection of a Beaufighter with 10cm H2S 
> radar was not the multi-cavity maggy, but the dang gas TR switch.

Yes, but the way the magnetron was use also was a surprise. Germany knew 
about the cavity magnetron, as did eveyone else. Like everyone else in 
the late 1930s, they looked at them as CW devices. Because a cavity 
magnetron does not do much (low power) in CW mode, they make crummy radar 
transmitters, so back then the things were shelved and forgotten.

The key Randall and Boot found to make the magnetron usable was to abuse 
it - whack it with a high voltage pulse. A quick look at the captured H2S 
set revealed the pulse circuits, and the cat was out of the bag.

William Donzelli
aw288@osfn.org