[AMPS] s meter calibration

[Bob & Linda McGraw K4TAX]

Peter, Larry as well as Tom, Dick & Harry:

Does it really make any difference about S meter calibration. As I
understand it, if the other station gives out 599's or 5 x 5's and finds
it necessary for you to repeat your QTH there's something wrong besides
the S meter calibration.

I vote for better receivers with "NO" S meters.

73
Bob K4TAX

Peter Chadwick wrote:
> 
> Larry says:
> 
> >So even with many hundreds of dollars spent on new purchases, many
> >thousands of dollars worth of my own test equipment, all the resources of
> >my lab at work, I don't know for sure if my power out is 1300 or 1500 or
> >1700 watts.
> 
> If you are an approved type testing laboratory, your typical conducted power
> measurement to a 95% confidence level is +/-0.75dB. That's 1262 to 1782 watts.
> Larry, you got any buddies at NIST who can calibrate a power meter at the 1500
> watt level to reduce errors in couplers etc?
> 
> You might get better accuracy using a liquid cooled load, measuring inlet and
> outlet temperatures with a constant head apparatus to maintain constant coolant
> flow, and then running a substitution with DC. If you keep the ambient
> temperature constant (I guess that's the amp in a different room to the air
> conditioned room in which the load is) I guess you may be able to get to about
> +/-0.4dB - maybe a bit better. Provided the amp is rated for key down operation
> for the length of time taken to achieve thermal equilibrium. That'll be +/-
> about 140 watts.
> 
> Worrying, this measurement accuracy business, isn't it?
> 
> 73
> 
> Peter G3RZP
> 
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