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Old October 20th 10, 04:58 PM posted to rec.radio.amateur.antenna
Mike Coslo[_2_] Mike Coslo[_2_] is offline
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First recorded activity by RadioBanter: Oct 2008
Posts: 91
Default Why do we short coil turns ?

On 10/18/10 6:23 PM, Cecil Moore wrote:
On Oct 18, 11:20 am, Jim wrote:
You can see that for this kind of coil, the coupling from turn to turn
must be pretty low.


For an average air-core coil, the delay through the coil seems to be
in the ballpark of half of the coil wire stretched into a straight
line, i.e. the VF of the coil is about double what is the VF of the
straight wire used to wind the coil. The turn to turn coupling exists
but turn to far away turn coupling is very low.

This seems to be the most accurate inductance calculator that I have
seen and includes the characteristic impedance and axial propagation
factor.



So to return to my real world example, an air core solenoid used as a
tuning coil for a bugcatcher antenna, would I be wanting to short the
unused portions of the coil, or leave them unshorted?

Seems that unshorted would be bad.

-73 de Mike N3LI -