This article is under construction; I decided to post it "as is " for completeness  because I wish to set up the 6229 magnetron page and need to reference it. The main part missing is details for the transformer construction; I am looking for my notebook which has the details; as best that I recall the input driver winding is 10T per leg that is center taped. The secondary has slightly more turns then 1/2  12VOLTS or more than 5 T ; 6 or 7 T ; I used a toroid power supply core that I found in my parts box; I plant to update this providing more details