[Milsurplus] Precision resistors in WW II gear

[telegrapher at att.net]

Seems to me that when i opened up some of my I-8x series test equipment 
for the command sets, i saw precision spool wound and other resistors 
with hand written labels.  The I-8x-B,C,D series were the single meter 
transmitter and receiver test sets.

Larry
W0OGH




WA5CAB at cs.com wrote:

> John,
> 
> I was following that thread.  The simple answer to your question is yes, most 
> resistors in voltage, current and resistance measuring equipment were 1%.  
> Combination instruments, like for example the I-135 test set for the BC-611, 
> used 1% meter multiplier and shunt resistors but 10% or 5% (depending upon year 
> of manufacture of the particular model) in the modulator and crystal test 
> oscillator.
> 
> But with regard to calibrating a TV-7, if the calibration settings were 
> developed for use of a 1000 ohm per volt voltmeter, then someone else's and then 
> your suggestion of shunting the available 20K ohm per volt instrument to 1000 
> ohms per volt is perfectly valid.  The circuit under adjustment will be unable 
> to tell the difference.  And what the voltage at the test point goes to when 
> you remove the meter is immaterial.  Assuming that whomever wrote the test specs 
> did it correctly, the test specs would have been developed to produce 
> satisfactory results after the adjustments had been made, not while they were being 
> made.
> 
> QED
> 
> In a message dated 5/23/2005 11:27:45 PM Central Daylight Time, jfor at quik.com 
> writes: 
> 
>>Has anyone seen extensive use of 1% or better resistors in WW II era gear? 
>>I
>>have not, except possibly for some meter shunts.
>>
>>The reason for the question is an argument on using 1000 or 20,000 ohm/volt 
>>VOMs
>>to calibrate a tube tester on another list. The 20K/volt is available, and I
>>suggested a shunt to make it 1K/volt. The counterclaim is the accuracy will 
>>be
>>inadequate, which I do not believe.
>>
> 
> 
> Robert Downs - Houston
> <http://www.wa5cab.com> (Web Store)
> MVPA 9480
> <wa5cab at cs.com> (Primary email)
> <wa5cab at houston.rr.com> (Backup email)
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