[Hallicrafters] S27 vs S27D etc. and S36 differences.

[Todd, KA1KAQ]

On Fri, Jul 30, 2010 at 4:08 AM, Brian Goldsmith
<brian.goldsmith at echo1.com.au> wrote:
> Greetings to all.
> Could some learned person on this list tell me what might the differences be
> between the Hallicrafters S27 and other S27 variants.I understand that a S36
> is similar but have no idea of the differences.


Hi Brian -

Not sure I'd call myself 'learned', but I'll take a shot at it. Back
in the 90s I did some research on these beasts and the roles they
played in WWII.

The S-27 was referred to as a 'Ultra High Frequency' set in its day,
though today we'd call it VHF as it covered from just below 10 meters
to 145 mc, including the present day FM broadcast band. AM/FM
reception. At the outset of WWII when the Germans were bombing the
snot out of England and their bombing beam-guidance system Knickebein
had been detected by the Brits, there was a rush to equip aircraft
with receivers capable of receiving those beams. The S-27 fit the
bill, so they bought up as many as they could find, including here in
the states.

I'm not familiar with the 27D, so I'll have to take a pass on that.
There was a 27C, at least temporarily, which was actually the
precursor to the S-37 except for using the older knobs of the 27 and a
different rectifier tube. More on that later.

The updated S-36 came along during the war and was essentially the
same receiver with subtle changes. The most noticeable(please excuse
me for not being able to cite the exact time line) was the addition on
another 956 acorn tube just before the aerial, for radiation
suppression. Dial coverage also dropped to 143 mc.

Interestingly, some early S-36 models have a stamped S-27 escutcheon.
Hallicrafters apparently decided to use up the stock they had on hand
since it was a wartime situation. The same thing happened when they
moved to the S-36A.

Now, back to the S-27C/S-37. This receiver covered 130 to 210 mc and
was also referred to as a Ultra High Frequency receiver, accurate in
this case. The odd thing is, despite both receivers having 'Ultra High
Frequency' stamped into their panels, The S-37 is referred to in its
manual as a Very High Frequency receiver. The 27C used the same
steering wheel tuning knob and smaller knobs as the S-27, SX-28, etc,
while the -37 used a different, newer style without the metal skirts.

The other big difference between the 27C/37 and the others is the
tuning dial: the 27C and 37 used a German Silver type of dial
arrangement like the earlier Super Skyriders, only utilizing the
celluloid type dial for bandspread.

One other point worth mentioning is longevity. Many folks think these
receivers basically ended production with WWII or there abouts. In
fact, a version of the S-36A was produced at least into the early to
mid 50s for the Navy as the RBK-16. The Navy started using these sets
with the RBK-1 (S-27) up through the RBK-16. It differs considerably
from its earlier brethren by having a more typical Navy light gray
paint job with silkscreened lettering. The panel itself is smooth
without the typical Halli 'cracked leather' stamping. The escutcheon
is also plain, no model number stamped into it. And the band knob is
changed from the older Hallicrafters H knob to a more generic bar knob
with a metal skirt like those used on the TCS and other Navy sets. The
-16 has no civilian counterpart.

The Army also used some of these sets, but the nomenclature escapes me
and I got rid of a lot of my excess manuals. These sets show up from
time to time, but nowhere near as often as the Navy RBK versions.

So there ya go, Brian. Hopefully there's something in there you can
use. Keep in mind that this info is from a rather cluttered mind and
may be off a bit in places. (o: These are really neat radios to play
with if their more specialized and limited frequency coverage doesn't
bother you. Best of all, they are great to use for FM broadcast as
they utilize a pair of 6V6GTs for wonderful push-pull audio output. At
roughly 80 lbs, they aren't exactly lightweights. But the build
quality and performance are both excellent for their day, akin to the
Halli SX-73 which was probably their best set overall IMO. Thought
it's hard to beat the SX-28, which the S-27 and -36 match up with
nicely.

~ Todd,  KA1KAQ/4