[Hammarlund] HQ140X

[Kenneth G. Gordon]

On 24 Mar 2014 at 14:31, GRANT YOUNGMAN wrote:

> I just did the alignment on an HQ-140X this past week.  Used a sweep generator
> and a scope with a log detector.  It was really instructive.

I first tried this method many years ago after reading a very short bit about it 
in either a Hammarlund or National alignment instructions for one particular 
receiver.

Over the years, I tried various methods to do it, not having any real 
instruction, and finally hit on it.

As you say, using it is VERY instructive.

My present system consists of a cheap B&K Sweep/Function Generator 
which outputs a sawtooth sync voltage. 

I use that to both 1) sync the horizontal sweep of my scope, and 2) to "FM" 
my HP-8640B signal generator.

For a detector, I tried several methods and can provide scope photos of what 
those methods resulted in. The best results were obtained by using an old 
Heathkit "RF Probe" coupled to the diode load resistor. This thing is very 
easy to duplicate, and consists of a low-pass filter built into the probe.

The low-pass filter eliminates all the "crap" from the traces and provides a 
perfect outline of the IF passband. Furthermore, it is "real time" so that any 
adjustment you make in any IF stage is immediately reflected in what you 
see on the screen.

Although it is certainly possible to get the same results by using a signal 
generator, a VTVM and graph paper, this method is far faster and one can 
see what is taking place instantly.

I very highly recommend it and plan to use no other method when aligning 
my BAs from now on.

YMMV.

Ken W7EKB