The AM Forum

Last night I aligned my BC-312M, 1944 WWII 1.5 to 18 Mc receiver. When I bought it back in the early eighties, my elmer said he was glad it was going to me because I wouldn't be poking my fingers around inside and screw up the alignment. Well that was true. I haven't messed with it until now. I did rebuild the power supply some years ago when it quit but that is all.

Wow, it really plays! I took it off the bench and hooked it up to my 80 meter dipole and matchbox and wow, signals everywhere!

I tuned through 40 to 7.160 and there was K4KYV full quiet. What a great signal, Don, and thanks for making my old radio sound so good! I am south of you near Fairview so usually you skip over me I think.

I wonder how often you guys re-align your receivers? My IF frequency took the most adjustment. I don't know if it was so far off for a reason but I re-aligned to the 470 khz as per the TM manual.

I don't know how the 312 stacks up to other receivers but except for limited selectivity, it does pretty dang good. And the audio is so much more enjoyable than the Kenwood Twins I normally use.

Anybody have any experience with the medium frequency cousin, BC-314?

Mark

My BC-348 and a couple of Hallicrafters that I have worked on had crystal filters. These typically drift with age, meaning the passband peak shifts. You want to be able to use the crystal filter to maximum effect so you have no choice but to buy another crystal or reallign the IF frequency.  I have found that the IF will generally move a few kc away from the specified frequency and as long as the HFO and RF trimmers will trim you back to proper dial and bandspread, everything works fine. The receiver really does not care if the IF is at 455 or 449 kc.

Mike WU2D