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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