Amps
[Top] [All Lists]

[AMPS] EXPERIMENTAL RESULTS ON SHORTED TURNS

To: <amps@contesting.com>
Subject: [AMPS] EXPERIMENTAL RESULTS ON SHORTED TURNS
From: measures@vc.net (Rich Measures)
Date: Fri, 25 Apr 97 10:12:42 -0800
>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   


--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com

<Prev in Thread] Current Thread [Next in Thread>