[Amps] AL-1500 pi-network capabilities

[Ian White, G3SEK]

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