In article , philo wrote:
http://www.radiomuseum.org/r/hallicr...r_s_35_s3.html

If it had the panoramic adapter, it would have been out of range of the
photo, but I am curious as to what such a device is. As far as I can
tell it's an oscilloscope that displays the band spectrum.

Yes, the panadaptor or bandscope is a spectrum analyzer that is attached
to the receiver's IF so that you can visually see all signals within the
IF range.

That receiver would likely have had a BC-1031 or APA-10 panadaptor.
A typical WWII aircraft install would be a Hallicrafters ARR-7 with an
APA-10 panadaptor.

If anyone knows I'd like to hear more about it and why it would be useful

It is great for countermeasures work, if you are looking rapidly for
an unknown frequency such as your enemy's communications or radar. It
is also an aid to identifying signal types for radar and telemetry.

For ham radio work it is also wonderful in a CW pileup because it makes it
much easier to find an empty place fast. It's handy for sweeping the band
doing hunt and pounce also.

I have a Heathkit SB-620 pandaptor on the output of my R-390A and it is
crude but workable. The IF output on the R-390 is after the mechanical
filters, so I have to set the filters wide in order to see 16kc worth of
spectrum, and then close them down once the signal is tuned in.

Many receivers designed for countermeasures work have a super wide IF
output that allows you to see a huge chunk of spectrum on the panadaptor,
much wider than audio bandwidth. That's much nicer, but you pay in front
end linearity by making it that wide.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."