Will Matney wrote:
Another good coil can be made by using a wide copper strip about 5/8"
wide and about 1/16" thick. Plating, etc. helps this too, and this can
be a good substitute for using tubing. Tubing is easier to form around
a mandrel though. Actually, if a piece of 1/4" tubing was split and
flattened out, it would equal a strip 7/8" wide. 3/16" will equal a
9/16" wide strip.
A small point: round tubing always has a lower RF resistance than a flat
strip of the same total surface area. Current tends to concentrate at
the corners of rectangular strip (and losses are proportional to
I-squared) so it isn't using the whole surface area at maximum
efficiency.
On the other hand, it isn't a huge effect, and there are lots of places
where flat strip is definitely a better shape for mechanical reasons.
Smooth flat strip, that is - not braid!
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|