On Fri, 9 Mar 2012 17:54:51 -0500, "Jim Wilkins"
wrote:

"Jim Wilkins" wrote in message
...
"Such receivers were not remotely tuned by the pilot, but were
instead
lock-tuned to the associated transmitter's frequency before
take-off."


http://aafradio.org/
"It seems that WWII pilots were notorious for having little patience
with their gadgets, and temporary loss of signal due to fading or the
like was often met with attempts at retuning the radio, usually ending
up off the assigned frequency. There were times when this loss of
communications led to tragic results. To counter this temptation, ARC
added temperature compensation and stabilized the local oscillator on
the R-25, R-26, and R-27 HF sets, so that once tuned to a particular
frequency by a ground technician it could be locked in place until the
next mission."

They should have stuck with crystals. I had an ARC 5 in 1960, which
had been converted to xtal control by another ham. It had five crystal
sockets and a switchbox. That would have solved their tuning problems.

--
Ed Huntress