On another news group this was posted:

http://www.alternatewars.com/Bomb_Lo...Bomb_Guide.htm


In the 5th photo down I spotted a Hallicrafters receiver which appears
to be an S-35



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.


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

philo wrote:

On another news group this was posted:

http://www.alternatewars.com/Bomb_Lo...Bomb_Guide.htm


In the 5th photo down I spotted a Hallicrafters receiver which appears
to be an S-35




The radio at the top of the rack is a Hallicrafters S-36.

On 01/30/2016 09:16 PM, analogdial wrote:
philo wrote:

On another news group this was posted:

http://www.alternatewars.com/Bomb_Lo...Bomb_Guide.htm


In the 5th photo down I spotted a Hallicrafters receiver which appears
to be an S-35




The radio at the top of the rack is a Hallicrafters S-36.




Yep, you nailed it I believe.


When I looked at the images I found on a Google search, I had seen an
S36A which slightly different, but still it would have been a closer
match than the S-36

Thank you

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."

On 01/31/2016 07:01 AM, 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.
--scott




Thanks for the great explanation! As "analogdial" pointed out, it's
actually an S 36 I did not examine the photos carefully enough

philo wrote:





Thanks for the great explanation! As "analogdial" pointed out, it's
actually an S 36 I did not examine the photos carefully enough

The S-36 has a panadaptor connection on the back of the chassis.
Altough I don't think it was often used.

It's a mediocre radio by today's standards. Not particularly sensitive
and the narrow bandwidth is way too wide for just one AM channel. The
wide bandwidth is a bit too narrow for fully modulated broadcast FM but
it wasn't too bad back in the day when some FMers broadcast with SCA.
Worked well for TV FM audio. The audio was very good.

I tried stagger tuning the IF transformers for wider bandwidth but that
hurt the sensitivity on wide and nearly killed it on narrow.

The damn thing was built to last. There's only one
paper capacitor, in the power supply filter. 8 ufd of
paper in a sealed steel can, if i recall. It's huge. I checked mine
for leakage and it was still no worse than an equivelant electrolytic,
so I left it alone. There's also one electrolytic (also in steel, looks
like an oil and paper, mine was no good) for the cathode bypass in the
audio amp. Everything else is silver mica. The resistors checked out
100%. Didn't look like any under chassis work had ever been
done on the radio. Amazing.

It has a really nice zero backlash gear drive. Probably the nicest
thing about the radio.

On 02/01/2016 01:54 PM, analogdial wrote:
philo wrote:





I tried stagger tuning the IF transformers for wider bandwidth but that
hurt the sensitivity on wide and nearly killed it on narrow.

The damn thing was built to last. There's only one
paper capacitor, in the power supply filter. 8 ufd of
paper in a sealed steel can, if i recall. It's huge. I checked mine
for leakage and it was still no worse than an equivelant electrolytic,
so I left it alone. There's also one electrolytic (also in steel, looks
like an oil and paper, mine was no good) for the cathode bypass in the
audio amp. Everything else is silver mica. The resistors checked out
100%. Didn't look like any under chassis work had ever been
done on the radio. Amazing.

It has a really nice zero backlash gear drive. Probably the nicest
thing about the radio.





I never had any Hallicrafters receivers but did once own an HT-32
transmitter. About the only piece of Ham gear I have left is a mint
condition HQ-140-X in completely original condition

On 2/1/2016 7:19 PM, philo wrote:
On 02/01/2016 01:54 PM, analogdial wrote:
philo wrote:





I tried stagger tuning the IF transformers for wider bandwidth but that
hurt the sensitivity on wide and nearly killed it on narrow.

The damn thing was built to last. There's only one
paper capacitor, in the power supply filter. 8 ufd of
paper in a sealed steel can, if i recall. It's huge. I checked mine
for leakage and it was still no worse than an equivelant electrolytic,
so I left it alone. There's also one electrolytic (also in steel, looks
like an oil and paper, mine was no good) for the cathode bypass in the
audio amp. Everything else is silver mica. The resistors checked out
100%. Didn't look like any under chassis work had ever been
done on the radio. Amazing.

It has a really nice zero backlash gear drive. Probably the nicest
thing about the radio.





I never had any Hallicrafters receivers but did once own an HT-32
transmitter. About the only piece of Ham gear I have left is a mint
condition HQ-140-X in completely original condition


My first receiver was a Hallicrafters SX-43. Paired with a Knight-Kit
T-60, I'd love to have both back again.

I've had a lot of fun in as a ham in the last 48 years, but I don't
think anything will compare with the QSO's I made as a novice with a
crystal rig and dipole.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

In article ,
analogdial wrote:
hilo wrote:





Thanks for the great explanation! As "analogdial" pointed out, it's
actually an S 36 I did not examine the photos carefully enough

The S-36 has a panadaptor connection on the back of the chassis.
Altough I don't think it was often used.

It does? I don't see that in the schematic on bama. Also, the IF frequency on the S-27/S-36/S-36A is 5250 Kc, not 455 or near there. So it would require a different panadapter, intended for use at that frequency.

I had, for several years an S-36A, which is almost, but not quite,
the same as as the non-A version. The S-27 prewar original was
also not all that different until you got into the detectors and
audio (used different tubes).

It's a mediocre radio by today's standards. Not particularly sensitive
and the narrow bandwidth is way too wide for just one AM channel. The
wide bandwidth is a bit too narrow for fully modulated broadcast FM but
it wasn't too bad back in the day when some FMers broadcast with SCA.
Worked well for TV FM audio. The audio was very good.

I tried stagger tuning the IF transformers for wider bandwidth but that
hurt the sensitivity on wide and nearly killed it on narrow.

The damn thing was built to last. There's only one
paper capacitor, in the power supply filter. 8 ufd of
paper in a sealed steel can, if i recall. It's huge. I checked mine
for leakage and it was still no worse than an equivelant electrolytic,
so I left it alone. There's also one electrolytic (also in steel, looks
like an oil and paper, mine was no good) for the cathode bypass in the
audio amp. Everything else is silver mica. The resistors checked out
100%. Didn't look like any under chassis work had ever been
done on the radio. Amazing.

It has a really nice zero backlash gear drive. Probably the nicest
thing about the radio.

Yes, it was "quite the radio" for its day. I spent a good deal of
time on my set. In general, on the lower two bands it had
reasonably good sensitivity and performance, but really got into
trouble on the third (highest) band, which started at the audio
carrier for TV channel 6 (postwar). That IF frequency was neither
fish nor fowl---too low for postwar commercial FM signals with 75
Khz deviation. As I recall, postwar FM receivers with 10.7 Mhx
IF's have a bandpass of 200 Khz or more, but with the S-36A, I
couldn't find a way to get flat response much above 160 Khz. That
meant that tuning was very critical. I tried loading resistors and
staggered tuning, but both just killed performance without
broadening the bandpass that much.

I had the IF transformers out of the set so that I could check the
coils on a Boonton 260A Q meter and a 250A RX meter. The IF's are
slug-tuned, and one section of one of them simply did not tune with
its slug. Rather than fuss too much with it, I simply replaced the
fixed capacitor in the can with a lower value and hung a trimmer
outside across the terminals. The 250A let me determine the values
and pretune the IF's before I reinstalled them. I see from the
schematic that the plain 36 used trimmers rather than slugs for IF
tuning.

The RF front end on my set when I got it was a mess. I took the
assembly out and took most of it apart to get it cleaned up. Once
again, the Boonton 250A and 260A were a great help in "getting the
Q back." One important thing about the S-27/36 is that it uses low
oscillator on band 3, but high on the other two bands.

One comment in the above discsussion, about a bypass cap in the
output tube cathode circuit, puzzled me. The S-36A did not have
one, but I see one in the non-A and S-27 schematics. Leaving that
cap out aids push-pull linearity, as any imbalance causes the
high-gain tube to act as a cathode follower driving the other half
as a grounded-grid amplifier. That configuration is at the core of
a lot of Tektronix vertical amplifier circuits.

The audio on this radio was incredibly good. The specs talk about
10 Khz at the high end, but my set would pass closer to 20 before
it hit 6db (voltage) down. The FM deemphasis filter installed in
the set was the prewar value---100 microseconds, as I recall.
Changed that to the postwar 75 microsecond values.

Yes, the tuning mechanicals on that set were very nice. That was
**after** I took it all apart, cleaned and relubricated it, and
replaced all the balls with new ones from a bearing supply place.

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

Hank wrote:


The S-36 has a panadaptor connection on the back of the chassis.
Altough I don't think it was often used.

It does? I don't see that in the schematic on bama. Also, the IF frequency on the S-27/S-36/S-36A is 5250 Kc, not 455 or near there. So it would require a different panadapter, intended for use at that frequency.


Mine does. It's a SO 239 connector, marked PAN, on a bakelite panel
beside the antenna binding posts and a another oddball
coaxial connector. It looks original although I suppose it could be a
repair depot mod. Doesn't look like a ham mod.

Don't remember what the oddball connector is for. It's not marked.


I had, for several years an S-36A, which is almost, but not quite,
the same as as the non-A version. The S-27 prewar original was
also not all that different until you got into the detectors and
audio (used different tubes).

It's a mediocre radio by today's standards. Not particularly sensitive
and the narrow bandwidth is way too wide for just one AM channel. The
wide bandwidth is a bit too narrow for fully modulated broadcast FM but
it wasn't too bad back in the day when some FMers broadcast with SCA.
Worked well for TV FM audio. The audio was very good.

I tried stagger tuning the IF transformers for wider bandwidth but that
hurt the sensitivity on wide and nearly killed it on narrow.

The damn thing was built to last. There's only one
paper capacitor, in the power supply filter. 8 ufd of
paper in a sealed steel can, if i recall. It's huge. I checked mine
for leakage and it was still no worse than an equivelant electrolytic,
so I left it alone. There's also one electrolytic (also in steel, looks
like an oil and paper, mine was no good) for the cathode bypass in the
audio amp. Everything else is silver mica. The resistors checked out
100%. Didn't look like any under chassis work had ever been
done on the radio. Amazing.

It has a really nice zero backlash gear drive. Probably the nicest
thing about the radio.

Yes, it was "quite the radio" for its day. I spent a good deal of
time on my set. In general, on the lower two bands it had
reasonably good sensitivity and performance, but really got into
trouble on the third (highest) band, which started at the audio
carrier for TV channel 6 (postwar). That IF frequency was neither
fish nor fowl---too low for postwar commercial FM signals with 75
Khz deviation. As I recall, postwar FM receivers with 10.7 Mhx
IF's have a bandpass of 200 Khz or more, but with the S-36A, I
couldn't find a way to get flat response much above 160 Khz. That
meant that tuning was very critical. I tried loading resistors and
staggered tuning, but both just killed performance without
broadening the bandpass that much.

Yeah, I was hoping that an alignment with a sweep generator and a scope
would allow for full FM bandwidth and some drift. Didn't work out and
it's never been an "active" radio for me.


I had the IF transformers out of the set so that I could check the
coils on a Boonton 260A Q meter and a 250A RX meter. The IF's are
slug-tuned, and one section of one of them simply did not tune with
its slug. Rather than fuss too much with it, I simply replaced the
fixed capacitor in the can with a lower value and hung a trimmer
outside across the terminals. The 250A let me determine the values
and pretune the IF's before I reinstalled them. I see from the
schematic that the plain 36 used trimmers rather than slugs for IF
tuning.

The RF front end on my set when I got it was a mess. I took the
assembly out and took most of it apart to get it cleaned up. Once
again, the Boonton 250A and 260A were a great help in "getting the
Q back." One important thing about the S-27/36 is that it uses low
oscillator on band 3, but high on the other two bands.

One comment in the above discsussion, about a bypass cap in the
output tube cathode circuit, puzzled me. The S-36A did not have
one, but I see one in the non-A and S-27 schematics. Leaving that
cap out aids push-pull linearity, as any imbalance causes the
high-gain tube to act as a cathode follower driving the other half
as a grounded-grid amplifier. That configuration is at the core of
a lot of Tektronix vertical amplifier circuits.

I didn't notice any difference in the sound with the new cap.


The audio on this radio was incredibly good. The specs talk about
10 Khz at the high end, but my set would pass closer to 20 before
it hit 6db (voltage) down. The FM deemphasis filter installed in
the set was the prewar value---100 microseconds, as I recall.
Changed that to the postwar 75 microsecond values.

Yes, the tuning mechanicals on that set were very nice. That was
**after** I took it all apart, cleaned and relubricated it, and
replaced all the balls with new ones from a bearing supply place.

The gear drive was working well except the ball retainer on the knob
shaft bearing had fallen apart. I got some extra balls and put them
in, one ball less than tight. Worked perfectly. The gear drive was in
good shape but I took on the challenge of disassembling and cleaning
it. My habit of looping a long piece of thread through the springs
saved me some trouble.

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