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[AMPS] Proper Wire Size for "L" Tank Coil?

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Subject: [AMPS] Proper Wire Size for "L" Tank Coil?
From: (Radio WC6W)
Date: Sun, 16 Jul 2000 13:59:42 EDT
On Sat, 15 Jul 2000 12:54:17 -0500 "Phil Clements" <>
>Much has been written for the proper size conductor
>to be used in the construction of tank coils, but very little
>data is available for the proper construction of the "L" coil in=20
>a Pi-L network, other than its value.  Is there a source for
>this ?

  Since the Q is (typically) rather low compared to the PI application,
the circulating current is also reasonable, requiring just a small
increase in wire size.     

>The torroid is very popular for this purpose, as it is more
>compact and self-shielding, allowing close-to -chassis mounting.
>Has anyone run any tests on the maximum power handling capability
>of such a coil?
  That depends mostly on the core and is easily calculated from the
numbers in a Micrometals (or Amidon) catalog.  If you need more power
capability you just stack cores.

>There is probably a formula for a simple "L" coil; given an image
>inductance of 300 ohms and 50 ohms output, but I have never seen

  Yes, there is  ...presuming you meant to type impedance immediately

  I think you can find it in the Orr Handbook... and probably the older
ARRL books... don't know about the new ones.  :-)

  Q = Square Root (Rin/Rout -1)   

  L = Rin / (Q * 2 * Pi * F) 

>I guess my bottom-line question is: what would a 9.5 uh 20 amp rated
>"L" coil look like?

  Just guessing that this is for 160M... #10 wire should suffice, either
a section of Air-Dux or wound on a toroid.

  Marv  WC6W


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