Fw: [Hallicrafters] Build your own R-42. It's easy!

[DW Holtman]

Craig,

Very interesting post. It got me thinking about the possibility of making 
the filter a little more selective. If I'm going to build one and the whole 
thing is not original why not? What I was thinking was maybe a 3 KHZ for 
communication and maybe 15 KHz for high fidelity(I think that the SX-42 
rolls off around 15 KHZ?)

If there a simple way to add a few more caps/inductors to improve the 
selectivity of the original Hallicrafters filter which only had two caps? I 
looked on line and throuth several years of the ARRL HandBook with no luck. 
Mostly active filters.

Any help or suggestions on how to improve athis filter without too much 
added on would be greatly appreciated.

73's
DW Holtman
WB7SSN

----- Original Message ----- 
From: "Craig Roberts" <crgrbrts at verizon.net>
To: "hallicrafters" <hallicrafters at mailman.qth.net>
Sent: Friday, January 21, 2005 11:18 AM
Subject: [Hallicrafters] Build your own R-42. It's easy!


> Hi y'all,
>
> A few days ago I asked for some technical information on the Hallicrafters 
> R-42 Reproducer -- a unit I used to own but sold many years ago, much to 
> my present regret. (I've just bought an SX-42 as my next restoration 
> project). I got several very nice and helpful responses (and even some 
> great pictures). Many, many thanks to those contributors.
>
> Using this info, I set about building my own "poor man's R-42" while I 
> scout around for the genuine article. I finished my "Genuine, imitation 
> R-42" a couple of nights ago and assembled a PDF document  containing 
> construction information and a parts list. I've posted it on my website 
> in case you'd like to experiment with constructing  your own, too.
>
> I'm still playing with cabinets for this imitation R-42, though it works 
> very nicely in a salvaged item I already had on hand. I'm sure I can build 
> an enclosure to make it sound even better, though. When I do, I'll pass 
> along plans and pictures (unless I find an actual R-42 in the meantime).
>
> To download the PDF, please visit my website and go to: 
> www.aerialacts.com/R42.pdf .
>
> 73!
>
> Craig
> W3CRR
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