[AMPS] EXPERIMENTAL RESULTS ON SHORTED TURNS

[Rich Measures]

>The results: 
>
>Open unused turns: F=4.8236 MHz, Q = 122
>Shorted turns:	   F=5.2293 MHz, Q = 99
>
>Not only did the Q decrease by about 20% but the effective
>inductance also decresed by about 20%.   Unfortunately I do not 
>have an coil of 5 micro Henries and the same construction to test 
>the Q with no unused turns.
Everything has a trade-off.  The trade-off with not shorting unused turns 
on a tapped coil is the chance of producing eyebrow-raising RF voltages 
across the unused turns.   I was sketical until I saw the result.  Now I 
always short unused turns.  Some builders aptly call it the Tesla Coil 
effect. 
 OTOH, if separate coils, oriented alternately at right angles. are used 
in lieu of a tapped coil, the losses you observed are obviated.  The 
trade-off is that doing so takes more chassis space than a tapped coil.  
Rich---

R. L. Measures, 805-386-3734, AG6K   


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