Re: S Meter Calibration (STRENGTH and RAWSTR)?

On Thursday 09 August 2007 09:27:50 Alexandru Csete wrote:
> Quoting Rob Frohne <frohro <at> wwc.edu>:
> > Hi All,
> >
> > Does anyone know how the calibration on the S meter should be set?  I am
> > trying to calibrate the S meter in grig.  Both STRENGTH and RAWSTR give
> > me the same number for the TS-850S.  (It looks like it goes from 0 to 30
> > approximately.)  What is the difference between RAWSTR and STRENGTH
> > supposed to be?
>
> RAWSTR is the raw value, which is usually rig specific. In this case it can
> be 0 to 30.
>
> STRENGTH is the signal strength in dB with S9 corresponding to 0dB. I don't
> know if there is any standard yet for how many dB per S-unit, but many rigs
> use 6dB, so S0 = -54dB. Grig (and I think xlog too) uses 6dB per S-unit.
> Note that the scaling between RAWSTR and STRENGTH is not necessarilly
> linear.

As I understand it, the commonly accepted value between S units is 6dB.  Very 
few radios meet that.  The radios I have placed on the bench and checked with 
a service monitor have not come any where close to a 6dB stepping nor have 
they been anywhere close to linear across the range.  They are, of course, 
refered to as "relative" signal strength meters.

In the backend code, the coder can only map to what the radio the coder has 
provides for values.  One unit of a given model is certainly not 
representative of a production run and certainly not indicative of an entire 
model series.

Okay, this is on a bit of a tangent.  

73, de Nate >>

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