[Hallicrafters] Hallicrafters SX-88

Wed Jul 22 05:37:50 EDT 2015

Jim, 

I see now you are correct as Jay made no direct reference to sweeping the IFs. He did mention using a spectrum analyzer so I assumed he adjusted the transformers with it. Without sweeping the IF stages individually there is no way to adjust the shape of each curve without flat topping them and hurting sensitivity. I recently obtained a Hewlett Packard 3585A spectrum analyzer so I'll be able to do that here now and it's planned for the next one when I reach that stage with it. Getting one's self in a position to be able to do a good job on these things is an expensive proposition and takes a lot of effort for just a hobby.

Regards, Greg
WA1KBQ

-----Original Message-----
From: Jim Liles <hallicrafterssr2000 at k9axn.com>
To: Greg Gore <wa1kbq at aol.com>; hallicrafters <hallicrafters at mailman.qth.net>
Sent: Tue, Jul 21, 2015 11:24 pm
Subject: Re: [Hallicrafters] Hallicrafters SX-88

Good morning Greg,

Don’t see any reference to Jays sweep analysis.  I’ll
contact Jay and check to see if he swept the band pass.  Seem like there’s only
a hand full of folks who have worked on these radios.

Thanks again  --- Kindest
regards Jim K9AXN 

-----Original Message----- 
From: Greg Gore 
Sent: Tuesday,
July 21, 2015 4:27 AM 
To: hallicrafterssr2000 at k9axn.com ;
hallicrafters at mailman.qth.net 
Subject: Re: [Hallicrafters] Hallicrafters SX-88

Jim, 

There is a good recent report of a comprehensive Hallicrafters SX-88
restoration with follow-up performance test results by Jay Rusgrove; W1VD
at:http://www.w1vd.com/HallicraftersSX-88.html  
Jay did measure the SX-88 50KC
IF transformer "Q" and it's actually better than we anticipated at 230. The
transformers Hallicrafters employed in other models using a 50KC 2nd IF system
are not quite like these. Jay also swept the 50KC IF's after a complete
electrical restoration and reports the curves do match the original engineering
design. 

Regards, Greg Gore
WA1KBQ

-----Original Message-----
From: Jim
Liles <hallicrafterssr2000 at k9axn.com>
To: hallicrafters
<hallicrafters at mailman.qth.net>; Roy Morgan <k1lky68 at gmail.com>
Sent: Sun, Jul
19, 2015 7:50 pm
Subject: Re: [Hallicrafters] Hallicrafters SX-88

I would like
to repeat an information request regarding the 50Kc I.F. system used in the
SX-88. -----Original Message----- From: Jim Liles Sent: Thursday, July 16, 2015
7:21 PM To: hallicrafters at mailman.qth.net ; Roy Morgan Subject: [Hallicrafters]
Hallicrafters SX-88 I have some questions regarding the SX-88. First have you
done a sweep analysis of the 50Kc I.F. system or do you know of someone who has?
At this point it appears that nobody has taken the time to sweep that system
---- anybody? Can anyone confirm that the 50Kc I.F. charts in the book are
correct? Looking at the design I would expect the shape factor for the system to
be close to 2.2/1 which is very close to the crystal filters of that time. Is
that a correct analysis? Has anyone measured the Q of the first, second , and
fourth 50Kc transformer pairs as well as the third pair? More questions but sure
would like to hear from those who have had one on the bench. That radio is
probably the most enigmatic of the Hallicrafters bunch. Always wanted to put one
through sea trials. Would like to hear both objective as well as subjective
opinions and test results. Sounds to be some strong feelings regarding that
radio’s performance. Please for the moment put the past aside and help me with
this project. Kindest regards Jim K9AXN
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