[NJARC] Coil Wire Questions

[Al Klase]

Hi Scott,

Comments below:

Scott Roberts wrote:
> Visit our web site - See http://www.njarc.org
> _______________________________________________
> A question for the R-F coil gurus-
>   
These coils are RF chokes, so you only need to come close.  It's not 
like a frequency determining tuned circuit.
> I am getting ready to build a couple coils I need to ressurect a BC-348-P Dynamotor assembly, and I am trying to ascertain exactly the wire I need. The description of the coil, actually an r-f choke(part no. 301 or 302- I think there is a mis-print in the manual) describes it as " 300 turns #30 single silk enameled wire". Does "Single Silk" perhaps mean "Single Strand", as opposed to multiple stranded? Makes sense to me... I have a very nice spool of #30 which is almost as old as the radio, and in great shape, which I cold use if this is the case...
>   
Old-time magnet wire was insulated with a winding of thread,. either 
silk or cotton.  There were single and double covered wire of both 
types.  This one has a single layer of silk over enamel.  The silk is 
probably there to make it easier to make a "universal" winding.  See 
this link for some pictures.  It's a little confusing that the site 
belongs to Universal Magnetics Inc. (Capital U):  
http://www.umiweb.com/9.html
> Also the description states "Universal winding 3/16" thick" I am assuming when I wind it, by hand is acceptable, as long as it is neat and tight?
Ill send a picture of the assembly from my BC-224 (12-volt BC-348) so 
you can see what's going on.  Unfortunately I can't get you a good look 
at the coils without wrecking them.  Looks like they may be multiple 
"pi" windings.
>  
>
> At the beginning, should the bottom most strand be wrapped under the rest of the coil to hold it in place?(i.e: the initial section is laid parallel to the center axis of the coil, and the wire then wrapped around, and over, the initial section, for the full depth of the winding)
>
> And the other coil I need to make is listed as "75 turns #15 AWG enameled, layer wound" Is #15 AWG available? I don't remember hearing about anything other than even size gauges before...
>   
When you get to motors and transformers,  the "odd" sizes of wire are 
often used to make everything fit the available space.  The subject 
coiul is wound on a spool.  I suspect you could fill such a spool with 
#16 or #14 and never know the difference.

Good luck,
Al

-- 
Al Klase - N3FRQ
Flemington, NJ
http://www.skywaves.ar88.net/