I've posted to your question on antiqueradios.com.
http://antiqueradios.com/forums/viewtopic.php?t=62667
http://www.nostalgiaair.org/PagesByModel/820/M0018820.pdf
Norm
:HI I was wanting to know if anyone can give me some infor on a double wound coil(i really havent a clue as wo wich one it is) on a sparton 570m or if there is a way to make a new one with the proper amount of windings? thank you,.,