Thursday, February 25, 2016

Antenna coil design - high C vs low C - high L vs low L

Assuming we could make our capacitor exactly as we want it. We pick a capacitor that will cover our frequency range without being to 'fast'.  The 50 Pfd capacitor will be difficult to tune. The 1000 Pfd will tune easily. In reality we have to select what's available.

The coil diameter will determine the turns per inch required to obtain the desired inductance. This in turn will determine the Q. More turns per inch require smaller wire which give lower Q.


As you look at this chart you could also consider the 'square coil'. Some authorities say the square coil gives the best compromise for the best Q. 

It's not an exact science because of strays. Stray capacitance and stray inductance will effect the circuit.

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