[AMPS] Pi-Net math

[Rich Measures]

Dick

>Rich...
>
> ........
>........... Time to do your homework.
>
€  I did the homework, Dick.  I built the Pi-network test model.  I used 
Ian's calculated values  for:  2000-ohms RL / Ro=50-ohms / 7.00MHz / Q=10 
or so.  
-  Ian's results: 
  "The accurate formula - in ARRL Handbooks since 1995 - gives 
C1=102.1pF,  L=5.57uH, C2=463.9pF. When analysed with the load present, 
this checks out with Q=9.98. "  

-  My results .  Without RL and Ro, the resonant freq. was 7.37MHz, which 
checks out mathematically.  When I connected the 2000 ohm and 50 ohm 
resistors, the resonant frequency did not appear to drop to 7.00MHz as 
had been predicted.  
Is there perhaps something that I am doing wrong, Dick?  .   Ian? .  Tom? 
 .  Peter?   Any suggestions would be greatly appreciated.  
>
>-----Original Message-----
>From:	Rich Measures [SMTP:measures@vc.net]
>Sent:	Friday, August 06, 1999 2:17 AM
>To:	amps@contesting.com
>Subject:	RE: [AMPS] Pi-Net math
>
>
>
>
>>
>>I'm with you, Ian. Someone on this reflector very recently stated the
>>basic,  fundamental definition of "Q" as "(energy stored)/(energy
>>dissipated)." I think "per cycle" is usually added. Ultimately that comes
>>down to the very general form of X/R or R/X.
>>
>>Seems to me the fundamental fact Rich continues to ignore is that you can't
>>define a loaded Q, which is what we're inherently dealing with in matching 
>>networks, without including the dissipative element(s).
>
>Eimac defines Q using RL.   Q = RL/XC1.    My contention is that with RL
>and Ro connected to the Pi-network, the resonant frequency is neither
>decreased nor increased.
>.....
>
>
>Rich...


-
-  Rich...
R. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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