[Amps] 4CX1500B

[R.Measures]

On Sep 22, 2005, at 12:09 PM, Peter Chadwick wrote:

> >With 0db attenuation, take the S meter reading at the adjacent
> frequency, tune to the fundamental frequency, add attenuation as 
> needed to give the same S-meter reading as before. The # of db of 
> attenuation
> is how many db down the total IMD is.<
>
>  
>
> Even this depends on how accurately you can set the S meter to the 
> same place.

So, do not use a meter that has sticky bearings.

> If we have a meter range to S9 + 40, and even 4 dB per S point, that's 
> a 76dB range. So to set to 1dB, you have to get the meter to within 
> around 1.5% of the same value - and on a speech signal, too.

The IMD level produced by the transmission of human speech can not be 
found by a 2-tone IMD test.  I use a steady "ahhhhhhhhh".
>
> 73
>
>  
>
> Peter W6/G3RZP
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org