[Elecraft] Elecraft] OT: Help designing power supply and toroid

[Allen C. Ward]

Hi Don,
As others have advised, winding the transformer is not as easy as it sounds and a ready-made one will do the job.  I think you should be more concerned with preventing RF noise on the AC line from getting into your power supply and hence into the Grundig radio.  Here is where toroid cores and capacitors come into play.  Do a search on emi and rfi filtering and then add filtering to the transformer, rectifier, regulator circuits as already described.  Cores and wire are available from Amidon and other sources.
GL
Allen KA5N