[kiwi_steve]

Cheers Richard. Thats the joys of working on other peoples stuff - it gets in the way of your own. I probably should be working on the AK708 I have here for someone... but I put it aside to do this one.

I think I've sorted the whistling... I went back and double-checked my sig-gen on a whim. I had thought its dial was accurate (it's not my main one, because I'm working in the spare room, not my workbench which is covered in the aforementioned Atwater Kent), but it was sitting around 490kc/s when I put the scope on it, so I re-tuned it to 470 using the scope, then re-aligned the I.F.s and its stable with the shield on now. Bit of a foolish mistake on my part - trusting the dial on an old sig gen. I've put a mark on the dial now for next time...

Cheers, Steve