[Hallicrafters] SX-100 Hints

[jim lockwood]

I've had four SX-100s over the years.  I still have and enjoy two of 
them.   Pretty radios, they work really well.

The one defect which ALL SX-100s have is frequency instability when 
subjected to any mechanical vibration.  Tap on the case or thump the 
table and the HFO in the SX-100 will QSY.

One of my SX-100s has had significant structural reinforcement added in 
and around the HFO to stop any parts of it from vibrating and changing 
frequency.  Doesn't help.

I've cured the instability by substituting an Arduino/Si5351 synthesized 
HFO for the HFO tube.  Now that SX-100 is immune to tapping on the case 
or even hammering on the table.

73,

Jim - K4CCF (ex-KM6NK)

On 5/5/2024 12:09 AM, Richard Knoppow wrote:
>    I don't have one and have not worked on one. I know mostly the 
> older models. However, I think if you look at the Hallicrafters 
> mailing list archive you will find a lot of material on the SX-100, 
> the are pretty popular.
>
> On 5/4/2024 5:36 PM, k5jwkgary at gmail.com wrote:
>> Any "hints" or "mods" available for the SX-100?
>>
>>
>> Thanks and 73,
>>
>>
>> Gary H. Harmon Jr
>>
>> 6003 Archwood
>>
>> San Antonio, TX 78239-1504
>>
>> (210) 657-1549 home
>>
>> (210) 884-6926 cell
>>
>> gharmon at idworld.net <mailto:gharmon at idworld.net>
>>
>> k5jwkgary at Gmail.com
>>
>>
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