In a message dated 98-02-03 16:22:25 EST, you write:
<< I made a choke using the 4 1/2 in. sewer pipe as a form and Times LMR-400U.
Times Microwave specify the minimum radius for this Ultraflex line as one
inch. While I wouldn't use RG-8 I feel relatively confident using the
LMR-400U for the 4 1/2 in. diameter choke.
If you examine the formula for inductance you will see that inductance is
directly proportional to to the diameter of the coil... i.e. the bigger the
coil diameter the fewer turns it takes for a given amount of inductance... So,
winding coax into a TOO small diameter of a coil is self defeating... It just
takes more turns to get the same inductance... Wind it on an 8 inch form with
an appropriate reduction in the turns count and "don't worry, be happy"...
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