On Fri, 21 Jan 2005, james moritz wrote:
What is diameter of wire #17 in millimeters? I'll do aproximate estimation
coil with Your formers. Though wire is coper...
...About 1.2mm, according to my ARRL handbook.
Acording to estimation done number of turns to get about 700 Ohms is 55
if former diameter is 320 mm. Optimal length of solinoid is about 160 mm.
If wire diameter is 1.2 mm then winding space/wire_diameter ratio will be
aproximatly optimal. This yelds Q about 300 but need turns to be not
close. If winding is by two wires close to each other then Q=240.
But there is an important notice in this case. If winding symmetry is not
ideal then parasitic current Ip shown on fig.1 in attaced file can
appeare. This can increase the loss. It will be better to connect two
equal parts of top load as shown on fig.2 not as on fig.1. This prevent
parasitic current appearence. If winding is close turn to turn with one
wire then as space/wire_diameter ratio as former_diameter/winding_length
ratio is not optimal. Then Q seems to be about 200.
N.B. Numbers are very approximative, solid copper wire assumed.
73 de RA9MB/Alex
http://www.qsl.net/ra9mb
fig.pdf
Description: Adobe PDF document
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