[Hallicrafters] SX-111 RF Alignment

[Bill Gerhold]

Thanks for all the advice and using that advice I decided to leave the
piston caps alone.  I headed the advice to adjust the oscillator
trimmers (coils) only.

Using my signal generator and an ICOM-756pro to confirm frequency, the
bands came in on target just fine with that one adjustment.  Saved me a
lot of work.  Thanks to all.  I think I'll close up the SX-111 and get
it on the air.

   73 from K2WH   
Hallicrafters, The Radio Mans Radio
            http://www.w9wze.org/
   http://groups.yahoo.com/group/The19Group/
 

-----Original Message-----
From: k0ewu at juno.com [mailto:k0ewu at juno.com] 
Sent: Sunday, November 28, 2004 3:43 AM
To: k2wh at optonline.net
Subject: Re: [Hallicrafters] SX-111 RF Alignment

Bill, those caps are set at final alignment and unless you change the
wire layout in the osc section--- leave them alone.
The later -111 have an oscillator trimmer for the "pointer alignment,
set
the coil slug at the low end then in actual use,
use the trimmer to set the frequency.   This assumes that the dial
pointer is mechanically set to the proper mark, one must slide the
pointer on the dial cord.
The cord can stretch in time and throw things off a bit.
[I have one on the bench right now with a very high1650 kc noise floor]
not good.
jack
On Sun, 28 Nov 2004 15:36:12 +0500 Bill Gerhold <k2wh at optonline.net>
writes:
> Gentlemen,
> 
> I am in the process of performing an IF and RF alignment on an 
> SX-111
> receiver.  The IF alignment was fairly easy and resulted in a good 
> improvement in the receiver sensitivity.
> 
> However, I have just started the RF alignment and I have run into a
> problem.
> The problem is the following capacitor oscillator trimmers.  C53, 
> 55,
> 57, 59, 60 & 63.  These trimmer caps are of a design I have never 
> seen
> before.
> They are tubular in shape.  The capacitor tuning slugs(?) ends are 
> not
> slotted to accept a tuning tool, but come to a point like a nail 
> but
> they do seem to be threaded.
> 
> In addition, the shafts are soldered to hinder movement once set at 
> the
> factory.  I can unsolder them but I need some advice and information 
> on
> how these capacitors are tuned/turned to alter their values.  
> Anyone
> have any ideas on this?
> 
> 
> P.S.  The IF on the SX-111 and other Hallicrafters receivers use a
> 50.75khz IF.  I used a wonderful piece of test equipment to make 
> sure
> the signal generator was right on the money.  An ICOM-756pro.  Makes 
> a
> great piece of lab equipment.
> 
>   73 from K2WH  
> Hallicrafters, The Radio Mans Radio
>             http://www.w9wze.org/
>    http://groups.yahoo.com/group/The19Group/
>  
> 
> 
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