[Boatanchors] Strange Hallicrafters S-38B

[Richard Knoppow]

     There are manuals for all the S-38 series on BAMA 
although some are pretty hard to read. KO4BB's are 
undoubtedly better.
     Whatever its labled on the panel the schematic calls it 
an automatic noise limiter.  Its a plain-Jane series 
limiter. Because of the way it functions the limiting point 
follows the carrier level so its "automatic".
     The S-38 had an additional tube to provide the BFO. 
They used a 6SQ7, which is a triode and dual diode.  The 
triode was used as the BFO, and one diode as the ANL.  The 
later versions of the S-38 used a regenerative arrangement 
to make the IF stage oscillate and provide the BFO, 
Hallicrafters had a patent on it. By eliminating the 
separate BFO Hallicrafters saved the cost of the tube, 
socket, variable inductance for BFO frequency control, the 
switch, and some wiring.  That made a lot of difference at a 
time when severe inflation made holding a price very 
difficult.  I think they could have used one section of the 
diode in the 12SQ7 in the later models as a noise limiter 
but it would have required a switch and some additional 
parts.  Not a lot until you begin to calculate the cost on a 
manufacturing basis.
     My first short wave receiver was an S-38B, bought new 
by my parents as the result of weeks of nagging.  I still 
have it.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com


----- Original Message ----- 
From: "Bry Carling" <bcarling at cfl.rr.com>
To: "puck.boat" <boatanchors at puck.nether.net>; "qth.boat" 
<boatanchors at mailman.qth.net>; "porch.boat" 
<boatanchors at theporch.com>; "Bob Jackson" <bob at nofrowns.net>
Sent: Friday, June 15, 2012 8:45 AM
Subject: Re: [Boatanchors] Strange Hallicrafters S-38B


> Hi Bob - Hallicrafters may have made some variants within 
> those model numbers, much like
> a lot of other manufacturers did, especially given that 
> theymade so many and over so many
> years. Yes, they seem to have dropped it after the plain 
> S38. I would love to know if there are
> examples of later models with stick ANL.
>
> For example, here is an original S38 with the "noise 
> limiter" switch:
> (I think it's OK to post links here)
>
> http://www.ohio.edu/people/postr/bapix/S_38one.JPG
>
> I noticed that it doesn't say ANL, but "noise limiter."
>
> All the S38B and following receivers that I have seen did 
> not have the ANL switch.
>
> They seem to have not made as many of the S38A as some 
> other models. I don't see as
> much about them. I have seen very few in person or even 
> pictures or discussions about
> them on the internet. But then I am  no expert on them. 
> Just have enjoyed using one or
> two S38s over the years. I think a variant may have been 
> sold under the Lafayette name too.
>
> KO4BB manual pages for S38A
>
> S38A in PDF form
>
> S38A in action
>
> It says that the S38D receivers were sold 1954 -1957 - and 
> I haven't seen one of those with
> ANL. Maybe Hallicrafters dropped it to save money?
>
> Incidentally - I have a boat load of new RF coils to 
> dispose of, and I prefer to let friends know
> about them, rather than use eBay, but I guess I won't 
> mention it here and irritate anyone. I
> have bought hundreds of items on eBay and probably sold 
> less than one per year over the
> past 6 years, LOL. For most of us eBay is a big time 
> waster, but it is handy when you need
> something you can't find elsewhere.
>
> 73 - Bry, AF4K
>
> On 15 Jun 2012 at 5:49, Bob Jackson wrote:
>
>> I'm pretty familiar with Hallicrafters S-38s from the 
>> original
>> through the "C" model and am aware of a few variants of 
>> the original
>> a la Dachis' book. However, before now, I'd never heard 
>> of (much
>> less seen) a "B" model with and ANL switch. I now own 
>> one. From what
>> I've always believed, the ANL circuitry was only in the 
>> original
>> version. Does anyone have any information on this and/or 
>> any other
>> variants?
>>
>> Thanks and 73 to all,
>>
>> Bob  AG5X