[Hammarlund] Re: Sweep Method for Alignment - ringing.

[Kenneth G. Gordon]

On 20 Apr 2006 at 10:45, Julian Bunn wrote:

> Hi Ken et al,
> 
> I have a followup question about the IF alignment with sweeps.
> 
> As you know, I was using this with success to align an HQ-110C.
> More recently I have been aligning a Hallicrafters SX-62. This
> has a crystal filter with "sharp", "medium" and "broad"
> positions. It's not clear to me at all how to proceed with
> the sweep alignment for the crystal filter positions. I assume
> the basic procedure is the same, but are there any nuances
> to be aware of?

What you have to do in that case is to be certain of the crystal 
frequency, then align to THAT not to the nominal IF. Usually the crystal 
frequency is not exactly centered on the theoretical IF frequency.

What I do is to first set the crystal filter in its most selective condition, 
and I make certain that the "phasing" capacitor is in its exact center. 
Often you have to take a look at the capacitor to make sure it is visually 
centered. Then, I do a sweep and look for the center of the sharp peak 
of the crystal, mark that position on my screen with a grease pencil, and 
align the IF to that.

Again, the lastest ER mag has an article on doing just what you wish. 
Although the author of that article was working on an SP-200, the 
principles and method are identical.

My method is pretty crude, but seems to work OK. His method is better.

Ken W7EKB