wrote:
hello,

After completing my AF amp and BFO, I'm in the process of doing IF/BFO
diode ring mixer.
I understood that it is a good idea (or even mandatory?) to follow DBM
with a diplexer.

I found one from http://www.qrp.pops.net/dip2.htm

My question is: how on earth should I wind those 10mH inductors? My
calculations show that I should wind 487 turns on FT37-43 (which is
obviously impossible), or 437 turns on FT50-43 (which is hard..but
should be possible).

Any other ideas how to make 10mH inductors for AF diplexer?

thanks!

I would be looking for a core with bobbin to make winding a lot
easier. Something like this:
http://cgi.ebay.com/FERRITE-TRANSFOR...mZ7597936903QQ
Is an over sized core, but would work. One 1/4 this size would also
work. I would add a thin gap (sheet of paper) between the core
halves, to make the inductance stable. You can chuck the bobbin in a
variable speed drill, by passing a bolt through it, and wind hundreds
of turns in a couple minutes. You can adjust the inductance with the
core gap, if you have a way to measure the inductance.