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 Post subject: Hallicrafters SX 101
PostPosted: Jun Wed 05, 2019 9:38 pm 
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I was given a beautiful Hallicrafters SX 101 HAM radio, an SX 101. I am looking for an owners/operating manual but all I find have the A (SX 101A) or Mark 1 or Mark II designation after the SX 101 on the back of the set. Can anyone tell me what manual would be appropriate?

Thanks


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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 10:08 am 
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Joined: Dec Sat 21, 2013 5:15 am
Posts: 427
Location: Puyallup, WA 98371
Try here:
http://bama.edebris.com/manuals/hallicra/
They have the SX101A, but also three versions (Mk I, II and III)
of the SX101. Download all three of them, and compare them
to your radio.

I downloaded the Mk I and Mk III manuals- the radios appear to
be externally identical, so operation should be very similar. One
difference I noticed with the Mk III is this:

Quote:
Electrically, the heating element and oscillator
filament transformer are wired across the AC line.
Thus, both will be on at all times while the receiver
is connected to a 117V AC outlet, even when the Response
Control is in the Power-Off pOSition.
NOTE
IT IS IMPORTANT THAT THE RECEIVER BE
PLUGGED IN A LIVE OUTLET AT ALL TIMES IN
ORDER TO OBTAIN OPTIMUM RESULTS FROM THE
HEATING ELEMENT. THE EXCELLENT DESIGN
INCORPORATED IN THIS SET WILL BE REALIZED
ONLY AFTER IT HAS BEEN PLUGGED INTO SUCH
AN OUTLET A MINIMUM OF 24 HOURS.


Sounds like the heater was added to make them
more stable (keeping them from drifting off frequency).
Wouldn't really affect how you actually operate it. It's a
lower end receiver (but still nice), so some drift would be
expected. I suspect even the heater didn't completely
resolve it.

I didn't get the Mk II manual, because it's in .djvu format,
and I don't have anything installed to open it.

Has the set been serviced in the past few years? If not,
you should have someone check it out for bad capacitors
and such. Plugging it in might be risking doing damage that
could be expensive to fix.

Enjoy your radio,

Dale


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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 10:59 am 
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Joined: Oct Sun 15, 2006 12:57 pm
Posts: 6631
Location: Liberty, Missouri
Quote:
... It's a lower end receiver (but still nice), so some drift would be expected...
The SX-101, and the subsequent "A" version, were the top of the Hallicrafters receiver line for quite some time, until the famous SX-115 was introduced. When properly tuned up, the SX-101 is a very good receiver. The big difference introduced in the "A" version was the product detector.

Virtually all receivers and tunable transmitters of the day had significant drift during warm up, and typical operation included a fifteen minute to half hour "warm up" period prior to operation. The heaters were a way to significantly reduce the time/drift problem. Hammarlund did the same thing in their top of the line, "A" versions of their HQ-170 and HQ-180 receivers.

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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 1:36 pm 
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And sadly, they dropped 160 meters when they added the 4 MHz band in the 30 MHz region to accommodate VHF converters. 160 was fairly useless back then due to Loran and FCC limitations, but I sure wish my '101A had the band.

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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 2:43 pm 
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I forgot about them dropping 160 on the "A". Mine is a straight SX-101 MkIII, which I bought just because it had 160.

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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 3:45 pm 
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I guess it made sense at the time with VHF gaining in popularity and 160 not being heavily used but I would also have preferred inclusion of 160. I have read of a few people who converted it back with a set of hand wound coils but using a simple external converter would be a more practical solution and a simple diode mixer would work well given the atmospheric noise level (and modern RFI pollution) in this frequency range.

Rodger WQ9E


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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 4:43 pm 
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I've thought of an external converter using a DBM mixer, problem is I can't find an off the shelf crystal that will work for 40 or 80 meters. Would be nice to have 3.8 mc correlate to 1.8 mc.

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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 4:56 pm 
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Peter,

One of these should work although you will get a little harmonic interference at the very top of the 160 band which shouldn't matter:

https://www.mouser.com/ProductDetail/AB ... ZqNpzuE%3D

Rodger WQ9E


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 Post subject: Re: Hallicrafters SX 101
PostPosted: Jun Sat 08, 2019 11:17 pm 
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Location: Liberty, Missouri
Another option would be to get one of these EPSON programmable dip oscillators.

Image

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