[ARC5] Now I'm completely OT - re "rushing design into production"

Mon Nov 16 19:50:30 EST 2015

Richard (and others)
You made the point that Mr. "Halli-craft" changed the design of sets
rapidly, and perhaps without sufficient thought.

Recently I listened to a historian contrast the manufacturing strategies
used by Nazi Germany and the USSR as it applied to tanks/panzers.  His
point:  the Russians thought through the full life-cycle of their T-34
(and subsequent models).  The life of a T-34 was about 8 to 12 months,
and everything was built according to that time frame.  The paint was
rough, the castings were rough, everything was rough.

The Russians stuck to their basic design - including a gear box that was
so "stiff" a hammer lay on the floor between the driver's feet.  In
contrast, the Germans constantly modified/improved their design -
according to the demand of the Wehrmacht.  The result was that the
Russian produced a huge number of their basic T-34, while the Germans
produced small numbers of superb panzers.  The historian made the
observation that the two contrasting strategies may have influenced the
final result of the war - an interesting conclusion.  

My comment (above) came from Richard's comment - that he suspected
"Hallicrafters rushed new designs into production too quickly to refine
them probably."   In the context of the "command" sets, it's interesting
(to me at least) to read about the delay between the presentation of the
'command' sets - some years before the first "decent" contract was let. 
It seems the "command/ARC-5" sets were subject to a LOT of preliminary
assessment (as I would expect from any military organization).  

There are some interesting side-effects of this.  A communication system
that provided a set or 3 radios in a rack, rather than one set with a
band-switch.  A communication system that lasted for many years
(although that may result from the pressure to not "rock the boat"
during a war, rather than excellent design).

As for me and the Hallicrafters "bottom of the line" S-38 sets - I
deliberately chose the early model (with B.F.O.) because a B.F.O. is a
distinct advantage (I think) over a regenerative I.F.   I want to
compare the performance of the S-38 with the performance of the 
"command" series or receivers.  History (and technology) IS interesting!

Thanks for your comment Richard!

73 de Les Smith
  vk2bcu at operamail.com

On Tue, Nov 17, 2015, at 06:12, Richard Knoppow wrote:
>     My first receiver was an S-38B, I may still have it but can't find 
> it. It was surprizing on a decent antenna.  When we moved out to Los 
> Angeles, about 1950, 10 meters was a an unprecedented peak. The S-38 
> could hear signals from all over on a 40 meter folded dipole.  I could 
> read SSB with care but the lack of an RF gain control made more 
> difference than lack of selectivity or stability.
>      The odd Hallicrafters arrangement for the BFO in this receiver is 
> to make the IF stage regenerative just at the point of oscillation. That 
> also makes it more selective. A resistor is switched in to reduce the IF 
> gain when the switch is set to CW, which helps because the regeneration 
> also increases the gain of the IF stage. A clever idea that sort of 
> works. The original S-38 had a real BFO and the extera tube also had a 
> diode in it so there was also a noise limiter.  The design change saved 
> a tube and some components but lost the noise limiter and ability to 
> shift the BFO frequency, the latter of not much value considering the 
> broad response.
>      I have a suspicion BTW that Hallicrafters rushed new designs into 
> production too quickly to refine them properly.   If I am right it would 
> explain the plethora of variations of models as ideas for either 
> reducing production cost or improving performance came up. Hallicrafters 
> was not the only company to make changes during production but perhaps 
> made more than usual.
> 
> On 11/16/2015 10:26 AM, Kenneth G. Gordon wrote:
> > On 16 Nov 2015 at 10:16, D C _Mac_ Macdonald wrote:
> >
> >> My first receiver (and transmitter) was the Walter Ashe $49.50 Novice
> >> Station with 6SN7GT regen receiver.  Worked a lot better than the S-38 I
> >> borrowed when the 6SN7GT went dead and I couldn't afford a replacement
> >> tube.
> > My first "good" receiver was a Hallicrafters S-41G which a plumber
> > sub-contractor for my step-father's construction company found in his
> > basement after he moved into the house. At least the BFO in that thing
> > worked....
> >
> > I bought an S-41G somewhat recently, mainly just to see how it worked when
> > compared with my more modern rigs. I almost can't figure out how we ever
> > used those things to make as many contacts as we did. Yet I even worked
> > DX
> > on 20 meters using the S-41G back then. The entire 20 meter band is not
> > quite 3/16" wide on the dial. Calibration was literally non-existent.
> >
> > I suppose the extremely poor selectivity of those sorts of receivers is
> > the primary reason I preferred to operate CW, and still do. The AM
> > portions of the bands were simply one huge collection of heterodynes. I
> > couldn't stand to listen to that crap for more than a few minutes.
> >
> >> My ears aren't as good as they once were, but newbies still can't figure
> >> out how I can pick signals out during Field Day!
> > Yes. I have had the same experience. My "wet filter" has a bandwidth of 50
> > Hz. It works just fine, thank you, even after all these years. I find
> > narrow bandwidths in modern receivers disconcerting: I can't tell what
> > else is going on on the band, and it bothers me. Besides, I also don't
> > like the sound of a restricted bandwidth. There are times, of course, when
> > very narrow (400Hz or so) bandwidths are useful...
> >
> >> There's still nothing that compares with trying to copy either ICW or
> >> voice signals under crowded conditions to improve operator skill.
> > Indeed, yes.
> >
> > I think Glen's idea of requiring new hams to spend at least 2 years using
> > wide bandwidth and unstable receivers is excellent, although impossible to
> > implement. Sadly.
> >
> > Ken W7EKB
> >
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> 
> -- 
> Richard Knoppow
> 1oldlens1 at ix.netcom.com
> WB6KBL
> 
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