Well, I wasn't for sure as I cant decipher what he wants. He mentioned  
wanting to know how to increase the inductance by 300 nH, which squeezing  
the coil would raise it. In a Pi-L, the load C is in between the two coils  
and tune C at the coupling capacitor off the anode. In other words, the  
added coil is between load C and the load. Without knowing what he wants  
to do for sure, about the only thing I could advise is answer his question  
about how to raise inductance by 300 nH. With a circuit description in  
detail, what he's wanting to accomplish, and at what frequency, I dont  
know what else to tell him. 
 
Will 
 
 
 
On Fri, 21 Jan 2005 13:22:02 EST, <Dennis12Amplify@aol.com> wrote: 
 
Will, 
I believe Chris is talking about converting from a PI network to  a Pi-L 
network. The Pi-L having two levels of impedance matching, and a little   
more 
harmonic suppression, than the original Pi network. 
 Thus the original Tune C becomes the middle capacitor of the Pi-L,   
allowing 
for a larger value of C, and the plate C is now the new Tune C. 
 Also, If his tune cap is already backed all the way out, he needs  LESS 
inductance in the tank to tune it, not more... Therefore he would be   
SPREADING 
the coil turns apart, or removing a turn, or moving the tap towards   
less turns, 
any of which would result in less inductance in the tank  circuit.... 
Regards, 
Dennis O. 
In a message dated 1/21/05 11:49:21 AM Central Standard Time, 
craxd1@ezwv.com writes: 
 
A 300 nH  coil (0.3 uH) is not very much. Assuming this would be the tank 
coil, the 10 meter end being the largest in size, one might just  squeeze 
the coils together to raise the inductance enough to bring  it in tune.  
If 
not, adding 1 to 2 turns of the same size wire, and  same diameter would 
most likely do it. A dip meter would be easier  to use to find the exact 
placing of the tap on the coil if it has  taps. According to the way the 
tube is ran and tube type, some at a  higher frequencies dont need a  
tune C 
in order to tune correctly  because the tubes output C is high enough and 
takes care of it. In  the amps I've seen this way, a load C was all that 
was  used. 
 
Will 
 
 On Fri, 21 Jan 2005 09:00:56 -0800, Chris  <rfcrazy@cox.net> wrote: 
 
Can anyone tell me what size wire  and dimensions to use for a 300 nH 
coil? I don't have an inductance  calculator.  I am having a problem  
with 
a 3cpx5000 that has high  C Out.  The tune vacuum cap is a backed all  
the 
way out in order  to tune. I read on web site that you can use a 300 nH 
coil from anode  to C1 to rectify this. 
Thanks for the help, 
 Chris
  
 
 
 
 
 
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