Charlie

Thanks for your post. I am well aware what the physical qualities,
tubes etc. that a RADAR of the period had.

In fact I have been researching the topic (with an eye toward writing
a book on the AI Radars of the war) for a couple of years now doing my
best to use original training documents, and "Notes on the use of
material", or manuals which were often not produced at all.

Anyway I though I may comment on your description of a wave guide. The
description I will quote is from a great little obscure book called
The Radar Army bt Reg Batt page 44.

"The next question was how to transfer this power to an aerial.
Coaxial cables of the type and quality then in existence were
considered too lossy. The possibility of using a waveguide was
considered. This was a whole new untried technique. The waveguide
consisted of a hollow metal tube having a critical diameter along
which the short radio waves could be propagated. It was decided to try
one.

We needed several yards of metal tubing of about two inches diameter
which for the purpose of the experiment was sufficiently close in
terms of wavelength to what was required. At the time we were given to
understand that we had acquired house gutter piping (in those days
zinc) bought from Edgar's ironmongers' shop in Swanage. But many years
later I was to learn from Jimmy Atkinson that it was vent piping
belonging to Elsan chemical toilet kits. These were stocked in main
stores, Elsans being the necessary form of sanitation at the Worth
Matravers site. It was a typical example of the Atkinson flair for
procurement, but since a number of kits had to be drawn in order to
provide sufficient piping, he was left with a somewhat bizarre
problem. The fact that we knew nothing of this at the time was
doubtless in order not to offend the sensibilities of those involved
with the experiment!"

All you need is some plumbing!

Waldo.