[Hallicrafters] SX-117 engineering changes

[Jim Liles]

Hi Jim:

The R48A set to voice, does a pretty good job of attenuating 60 cycles.  In normal mode 60 cycles is not bothered comes through like anything else.  There are a bunch of radios out there that experience the hum on the R48A when in normal mode.  

For me, the audio from the R48A in normal mode is very pleasant and intelligible for me.

My favorite radio required some extraordinary changes in order to reduce the hum to a point where it was inaudible with the R48A.  It also has some of the best SSB audio out there.

Kindest regards Jim K9AXN




-----Original Message----- 
From: Jim Wilhite 
Sent: Saturday, March 08, 2014 4:07 PM 
To: hallicrafters at mailman.qth.net 
Subject: Re: [Hallicrafters] SX-117 engineering changes 

I sold it some 5 or so years back to the guy who sold it to me.  I had it, 
the HT 44 and matching PS/Speaker.  They had a few problems that I fixed 
then I used them for a while and when the guy found out what had happened he 
wanted them back.  So I sold them to him for what I paid.  He is a nice guy. 
During the time I had it, I made the changes you mentioned and simply 
aligned the receiver.  The transmitter required some resistor changes in the 
carrier balance circuit to stabilize it and that was about all.

So fast forward to about last fall when another friend has this SX 122 and 
wanted to sell it.  He asked what I considered a reasonable price for it, 
the R-48A speaker and the radio had the crystal calibrator.  It had problems 
on the lower end of the top band which I fixed and it works very well now. 
The only thing is it has a hum in the speaker when the switch is on Normal. 
I haven't looked carefully but it is really irritating.  When you switch the 
cap out to receive Voice, the hum disappears.

Good receiver but I probably will sell it this hamfest season, I have 
lowered my boatanchor count and have 3 other receivers and that is really 
too many.

This one is a clean one with very few scratches on the paint and the chassis 
is very clean.  I like it almost as well as the 117 but that triple 
conversion has its advantages.

Jim
W5JO


-----Original Message----- 


If you have a SX-117 you REALLY need to review the multi-part article in ER. 
I made the changes and it's now one of my 'keepers'...

ron
N4UE






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