[AMPS] Fw: Two Tone Tests

[measures]

>
>
>----- Original Message -----
>From: Lamb <k7fm@teleport.com>
>To: <k5ra@mail.pulse.net>
>Sent: Wednesday, December 22, 1999 9:11 PM
>Subject: Re: Two Tone Tests
>
>
>> I agree that 2 tone tests are not conclusive.  But, I only stated that:
>>
>> "Once you argue that the cause for distortion is excessive grid current,
>> then you must accept succesful plots of 2 tone tests as proof that
>> either  the G2DAF circuitry does not have excessive grid current or that
>> it does not matter."
>>
>> If the G2DAF can pass a 2 tone imd test, it does not prove that it does not
>> have intermod. or that it does not splatter.  However,  it has been argued
>> that the G2DAF circuit has so much grid current that it cannot be linear,
>> and the worst case would be at full drive during a 2 tone test.  Passing the
>> 2 tone test would simply prove that  the G2DAF circuit does not develop
>> "too" much grid current to be linear.  It can be non-linear for other
>> reasons - but not excessive grid current.
>>
>> In this case, the 2 tone test would simply disprove something.  And,
>> sometimes knowledge is obtained by eliminating falsehoods and concentrating
>> on the facts.
>>
€  The question is How Much grid-current?  0.5Ma of grid-current is a 
whole nuther ballgame than 15mA of grid-current.  .  When I was measuring 
 on-the-air distortion of the two, DAF amplifiers, I observed that 
distortion level changed according to how much grid current was present.  
More grid current produced more power but it also made more doo-doo. //   
 In my opinion, two reasons for DAF distortion during voice operation are 
grid-current and the effect of the 3/2-power law (screen potential 
unregulation)  . During a two-tone test (where screen potential is 
constant) low grid-current can produce an acceptable distortion level.  . 
  High grid-current won't.  
-  For me, the DAF experience proved to be a valuable primer to gaining 
an understanding of how religious cults use reinforcement of denial to 
maintain control of members.  In effect, for a year or so, California had 
two well-known hams who had been sucked into the DAF cult.  It was a 
virtual excursion on the long river in the Land of Pharoahs.  
 
later, Colin

-  Rich..., 805.386.3734, www.vcnet.com/measures.  


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