[Hammarlund] HQ-110 alignment - the "visual" alignment method.

[RJ Mattson]

Hi all,
I use a Wavetek 134  sweep generator. range: 20hz to 2 MHz. Beware - Not 
many TV service sweep generators available will cover the low IF frequencies 
of comm rcvrs.
The Wavetek has a variable sweep time and at the moment I am adjusting a 
1650 kHz two xtal IF stage in my homebrew rcvr.
The sweep range is set to 1s to 100ms and I always lower the sweep until it 
is just bearable to watch the fading phosphors plot the bandpass on the 
scope.
A nice function is to have freq markers so you know where you are and you 
can calc bandwidth. I could never get markers to show up until I built 
myself a glowbug 6SN7 post marker generator attachment. Now I can see pips 
on the bandpass waveform injected from my signal generator or xtal 
calibrator.
The Hammarlund HQ-120x and 129x etc are just impossible to align without 
sweeping the IF.
I would attach an URL to show my setup but then the post would never make it 
to this reflector. Anyone else have this problem or know what my problem is?
Regards all,
bob...w2ami

----- Original Message ----- > The only thing the fast rate will do is to 
limit how narrow a
> bandwidth you can reasonably expect to measure.
>
> At 1ms sweep rate, any bandwidth near or below 1 kHz will be dubious -
> that is, what you see won't necessarily have anything to do with the
> "actual" filter response. A filter with a 1 kHz bandpass takes a
> couple of milliseconds to wake up and hear the electrons rumbling down
> the wire, much less decide what it is going to do with them.
You're right, of course, and I was wrong. Ya gotta keep that sweep
generator moving SLOOOOWLY so the IF stage doesn't ring and give
you false indications.

> . . . but it is still a really cool setup! I gotta get me one of them
> sweep generators.

I use a cheap B&K sweep generator, and it works like a charm. I have
seen them for sale on eBay for around $50.00.