help with a coil build

[golfnut]

yes thats good on a surf

[qute1]

now if i could just change the annoying whine of the surf to a nice geiger tick i would be sorted.

[nonkapo]

You can use coil calculator to predict your inductance like for single wire.
Real inductance may be a little different depending how coil tight.
But difference 10-20% in inductance may be tolerated.
I have heard that Surf PI works from 230 mH to even 400 mH.

So i get part of my question answered. However i'm interested where i can burn the FET or damage the detector? Which are the critical values in terms of induction and resistance Minimum/Maximum values of both?

Thanks.

[qute1]

Mosfet is the only part of detector that could sustain damage if it sees too low of a resistance (short) or too high an inductance (high ring back voltage exceeding fets specs) from the coil.
Should not be a problem unless below about .4 ohms or above 1.8mh (1.8 milli henry = 1800 uh).

I have heard that Surf PI works from 230 mH to even 400 mH.

230-400mH is a typo!!!!

[nonkapo]

Well is this not a mistake? Dont he mean 230uH to 400uH??? Eg 0,23mH to 0,4mH???

[qute1]

yes a typographic error indeed.