[Hammarlund] HQ140X

[Bill Kulze]

-----Original Message-----
From:] On Behalf Of GRANT YOUNGMAN
Subject: Re: [Hammarlund] HQ140X

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.

You can simply peak all of the transformers on the crystal frequency.  You will actually get a higher maximum IF output doing that, but you also will get a narrower "peaky"  passband with a funky shape rather than something with a nice symmetrical shape and a flat (well, really somewhat rounded) top.

Bill's idea is correct - you really do want to try to get a symmetrical passband if possible.  The radio will sound better with greater fidelity.  It's tedious to do by hand, but will give you a better result if you have the patience for it.  Z3 is the most critical to the overall shape.  Also the top core on Z4.  The bottom core on Z4 did not change the overall passband shape much, just the gain.

Do it the way the manual recommends.  One stage at a time starting with the last IF amp and moving towards the front of the chain.

Grant NQ5T
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When I first got the 129x I did the 'peak them all' method, not even at xtal resonance, wasn't real impressed with the sound. When I used the scope I found that peaking at center doesn't give you a true peak at center. It merely gets you the max level the center can be, the peak is off center someplace, you won't notice without moving the generator back and forth. I think that's what made it sound bad, having the peak in some other place in the pass band. I discovered this almost by accident after I recapped it and decided to do the alignment at the detector using a scope instead of a meter. It sure made a difference in audio! At first I was concerned about losing some gain by flattening the IF out a bit, but the darn thing has plenty of gain to spare.

Adjusting 'by the ear' might get you close, but the visual reference makes it much easier.

I would think the proper method with a sweep generator synced with a scope is best, but I would recommend doing this at the very least if you don't have the equipment to do it proper.

Bill
W2NVD