Hi Scott, There is an optimum form factor for maximum inductance per unit of wire, and another for minimum capactitance for a given inductance. This is all old knowledge -- See either the 1937 or 1943 Terman books. There are also other cogent factors: What you have or can acquire and... what will fit in the available space. :-) An interesting discussion of Tank circuits may be found in 73 Magazine, Feb. 1962, p12... Incidently the formulas found for Pi-nets in the ARRL handbooks were calculated from an ancient approximation and exhibit some noticable error at lower transformation ratios. There was an article with the correct math in QST, August 1983 p.23... Plate load resistance for given operating conditions may typically be found on a tube's data sheet. A copy of "Care & Feeding of Power Grid Tubes" by Eimac/Varian/CPI (any edition 1970's thru current) may also prove enlightening. 73 & Good morning, Marv WC6W http://wc6w.50webs.com/ -- "Scott & Laura Goldensoph" wrote: I have looked at these and they still leave me scratching my head. One example: How do you determine the diameter of the tank circuit? How do you figure the optimum load resistance? I've gone through the formulas in the 2005 ARRL handbook and it does explain it some but not from a beginners standpoint. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps ________________________________________________________________________ Try Juno Platinum for Free! Then, only $9.95/month! Unlimited Internet Access with 1GB of Email Storage. Visit http://www.juno.com/value to sign up today!