[ARC5] 6AQ5 Tank

[David Stinson]

Ok all you smart people-
I'm looking at a 6AQ5 Pierce crystal oscillator/tripler 
with a plate tank circuit which outputs at 24 MC.
The plate tank capacitor is 40 pFd. 
The capacitive reactance at 24 MC is only 166 ohms.
This seems low for a tube tank.  Output capac.
of 6AQ5  is 6 pFd,  so that doesn't change the picture much.
I was looking at changing the tank to output at 3.9 MC,
but if Xc = 166 ohms is correct, the tank cap 
at 3.9 MC would be 6.7 uFd.  That can't be right.
What's up with this?