[HBR] 24-5P Molded Coil Forms

[Jim Hill]

Rob:
I have never seen a construction article.  It's a commercial receiver 
using a special variable capacitor, plus a hard-to-find audio 
inductor. SW-3 Pix's can be seen at 
https://images.search.yahoo.com/yhs/search?p=sw-3+receiver&fr=yhs-mozilla-001&hspart=mozilla&hsimp=yhs-001&imgurl=http%3A%2F%2Fwww.qsl.net%2Fla5ki%2Forg%2Fna%2Fsw3_3.jpg#id=6&iurl=http%3A%2F%2Fwww.qsl.net%2Fab0cw%2Fsw3-5.jpg&action=click 
eBay lists them from time to time, so more pix's, etc. are available there.

More info is available at http://www.boatanchors.org/SW3.htm,  which 
includes a link to an article in an early issue of QST that covers 
the design.  The repro isn't the best, and if you belong to the ARRL, 
free online copies of earlier back issues QST are available with 
better resolution through their web site.

There are better links covering the SW-3, but I cannot find them now.

If you are interested in building regen receivers in general, join 
regenrx at yahoogroups.com

There are two groups/reflectors covering National radio equipment; 
you could query them about homebrew SW-3's; 
nationalradio at yahoogroups.com  The reflector is national at mailman.qth.net.
Go to http://mailman.qth.net/mailman/listinfo to subscribe.  After 
writing this, I noticed I'm duplicating another post.  It is easier 
to just include the dup.

Paul:
I'm leaving for a long weekend tomorrow, but when I return I'll 
measure coil dimensions.  If it sounds like a good idea, I suggest 
you query the National groups and see if there's interest, 
particularly since your coils are clear and the National coils are 
light brown.  I can also loan you a socket that someone included as 
part of a wave meter made years ago.  The wave meter is well made, so 
I never attempted to remove the socket.

I have never seen a HBR receiver, but remember the original articles in QST.

73's Jim

At 09:07 AM 11/8/2016, Rob wrote:
>Can you point to any magazine article that shows how to build this SW-3?
>
>On 11/08/2016 11:46 AM, Jim Hill wrote:
>>At 07:32 AM 11/3/2016, Paul Dulaff wrote:
>>If additional coil sales would reduce startup costs, I suggest you 
>>also look into manufacturing National SW-3 coil forms.  The SW-3 
>>was a regenerative receiver sold in the early 30's, and is 
>>currently a very desirable item.  It uses a 6-pin coil form with 
>>normal pin diameters, but with different pin spacing (since the 
>>receiver was designed and originally sold before 6-pin tubes were 
>>available).  If you are interested, I'll provide details.
>>Jim
>>
>>At 07:32 AM 11/3/2016, Paul Dulaff wrote:
>>>All
>>>Looking at the potential for tooling up, in a low cost way, the 
>>>HBR coil form. This would be an exact piece, injection molded 
>>>clear styrene with 5 pins, tin plated.
>>>Looking at tooling cost and cost for pins, the piece price hits 
>>>$10.00 each to recoup the setup and tooling costs for volumes in 
>>>the hundreds of parts.
>>>snip
>>>Paul - WB2NMI
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