[AMRadio] Ranger Modulation


KA5MIR ars.ka5mir at gmail.com
Thu Nov 16 15:24:50 EST 2006


Hello Jack,
  I doubt you could hear much difference between 55 and 90ma resting current.  
The tradeoffs are less linearity (raspy audio) if the resting current is too 
low and more dissipation (heat) generated by the modulators if it's too 
high.  That's almost certainly not your problem.

  Connecting your audio generator to the mic input and tracing the sine wave 
through your audio stages with an Oscilloscope can be fun and educational if 
you like that kind of stuff.  That might help you zero in on the problem.

73',
KA5MIR


> ... 
> Now I notice another discrepancy..... the manual that came
> with it says to adjust the mod current to 75-90 ma.
> The manual that Rick sent me for the new version which
> I seem to have says 55-70 and no clue why the difference.
> I presume that was a typo.  Does anyone challenge this?
> What is the effect of different modulator current values.
> Changing it risks breaking the wire on that resistor...
> which BTW, Rick sent to me as a gift.
> ...
> js



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