I have been building the through-hole BITX20 v3B from Sunil Lakhani. After a good bit of trouble shooting, and a frustratingly illusive shorted solder joint, I was finally able to hear a signal from my signal generator all the way thorough the receiver!
The problem I'm experiencing however, is that I was unable to fit 50 turns of #35 wire on an FT37-6.
I think I finally had 39 turns before I ran out of space. And they're tightly packed! Thus my VFO runs at about 5MHz rather than in the 4MHz range.
Do you know of any solution for this? Is it okay to have multiple layers of windings on the core?