On 02/04/2016 11:19 PM, Hank wrote:
In article ,
analogdial wrote:


snipped for brevity
That was about 25 years ago, so I've probably forgotten some
things. As a radio, it was an interesting foray into studying 1940
state-of-the-art as well as quite impressive-looking. But compared
to even early postwar designs, the set simply fell flat on its face
at around 100 Mhz---not particularly sensitive, poor image
rejection, and either too broad on AM or too narrow on FM. As I
recall, that set ended up (with an early stereo converter) in the
lobby of a non-com classical station as a lobby monitor.

Hank



Wow, great account!


I never had much test equipment so simply tuned to a weak signal and
tweaked "by ear" as best as possible.


As to working on transmitters, we always joked: Tune for minimum smoke!

Scott Dorsey wrote:

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.


The spectrum displays we built for our telemetry products were fed
from the second IF in a triple conversion system.

http://www.ebay.com/itm/181264716726 is an example of the 1161-S(A)
for the 1100 series receivers. The other models were very similar, with
different mounts, and either +/-12 Volt or +/- 15 Volt operation. That
rectangular (early units used Sylvania) CRT was very hard to buy, when I
left the company and we had to reject a lot of them because the new OEM
couldn't align the deflection plates properly.