[Radio Wrangler]

Let's chuck in one more thing about receiver alignment, affecting classic comms receivers.

Some sets like the better Hallicrafters, the AR88, HRO, etc have switched selectivity with some setting adding a crystal half-lattice filter into the mix for a nice narrow bandwidth for CW reception.

The crystals weren't made any more accurately than they needed to be for this fairly undemanding application, also people setting up the LC bandwidths often relied on the markings of their sig gen and could be a bit off.

The result is that the IF peak shifts when you engage the crystal and peaking on the crystal might be a bit down on the LC filtering shape.

The solution is to tune up the LC stages to suit the unadjustable crystal. You may not be dead on the specified IF number, but at least all resonators are singing the same song in the same key.

It gives you the freedom to switch the bandwidth narrower without having to find the signal again.

So good alignment instructions have you do the crystal ranges first.

David