There's been a lot of stuff here lately on calculating or measuring the UNLOADED Q of a TC. I think this is mostly a waste of time, although I do it myself for amusement. The real LOADED Q of any decent coil will be very much lower than the UNLOADED, or the efficiency would be very low. Best way to estimate Q is to try to measure the decay of each output impulse and calculate the logarithmic decrement, which as I recall is PI/Q. Ed