In message , The
Enlightenment writes

"William Donzelli" wrote in message
. com...
"Emmanuel Gustin" wrote in
message ...

It was technically quite difficult to provide a smooth control
that had a more or less natural 'feel' for the gunner, was capable
of
high speeds of rotation but also of accurate slow tracking, and
had
no dead spots anywhere where movement wasn't linked correctly
to control input -- for example when passing the 0 degree line
from
left to right, where the forces working on the turret reversed.

This I do not understand. The radar antennas of the era often used
synchro feedback systems - synchros do not have dead spots, they
provide a rotational signal from 0 to 360 with no interruptions when
making the 359 to 0 transition. What was the problem with the
control systems in the turrets?

Very hard. The electronics of the period used numerous
vacuum tubes which had a short lifetime.

Only hard working transmitter and radar tubes had short lifespans
(often just 50 hours). The tubes found in just about everything else
were quite hardy - most outlasted the war and are still good today.
Many small signal tubes often clocked lives well past 10,000
operating
hours.

William Donzelli



The tubes involved were special power amplifier tubes with heavy anode
cathode currents that must have been erosive. I do not believe they
had nearly 10,000 hours life. Amplifying DC was not possible because
directly unlike today when complimentary npn and pnp transistors are
available only valves were available and they had very particular
biasing requirements.

Most of the valves were similar to civilian valves, some were
'ruggedised'. Radio and TV valves had lives longer than 10,000 hours.

Mike
--
M.J.Powell