Still More Expert HRO Advice Needed!

[ashart]

Now I've moved into the xtal filter area.  That too, generates questions.  I guess that the old saying about nothing ever being easy, is correct.

(Q1)  Nowhere in my HRO-60 manual's alignment instructions, can I find any reference to L-12.  That designation comes from Fig. 6 on page 16, pointing to the slug in the "northwest" corner of the Xtal Filter enclosure.

Did I miss it, or did the checkers in National's drafting department?

Inspection of the schematic suggests it be treated like any other 455 tuned circuits, i.e., L2 - L11, and so that"s what I did.  It seemed to tune properly.  Did I do good or did I make another classic w8vr blunder?

Again dredging for relevant comments!

73 de al hart, w8vr

[w3jn]

Comparing the HRO-50 IF alignment instructions to the HRO-60 leads me to believe that when they're talking about peaking L13 2 KC higher they actually mean L12.  Or, perhaps not.

In any event at that stage in the radio, alignment shouldn't be too critical.  L13 should have more of an effect on the xtal filter performance than L12.

[KX5JT]

Why are you making new threads each time for the same thing?  This would be much more coherent for future reference if it were all in one thread!  Don't ya think?

[ashart]

In my opinion, each thread is not for the same thing, but asks a completely different question.

I think that's necessary to keep the questions separate, as the questions are complex and if bundled into one thread would be very confusing.  At least to me, if not to others!  


73 de al hart, w8vr

[KX5JT]

 

[AL7FS]

I could agree keeping that questions separate is a good thing if the subject line clearly states the question area.

HRO-60 - L-12-Crystal Filter Area question
HRO-60 - finding the correct I.F. frequency for alignment
HRO-60 - Adjusting the phasing control

Searching on "Expert HRO Advice needed" is not going to do it for me.

It turns out I just obtained an HRO-60 this summer so these topics are of great interest to me and each one is being saved to my hard drive.  Clear Subject lines can make a world of difference.

Thanks.

73, Jim, AL7FS
Anchorage, Alaska

[ashart]

Jim:

Good idea.  Hopefully, future questions will be of lower frequency than those of the past, but I'll definitely be more specific in the title.

Thanks fer the suggestion.

73 de al hart, w8vr.

[w3jn]

I think it would be best if all your questions regarding one project are in one thread.

[Jim, W5JO]

Al, that L 12 is the output of the last IF into the crystal filter so you should peak it on the IF alignment frequency before you move to the crystal filter alignment.  Remember the crystal filter is like a notch and, if I recall, after aligning the IF to the frequency of the crystal, you set the Crystal filter switch to 1 and move the frequency generator to 2 KC above the crystal frequency to set L 13.

[ashart]

Thanks, Jim.  I agree with your findings, and I now have it all aligned ok, except for the spec stating that the trimmer cap C-36 should be set to provide a Phasing-control notch separation of 180 degrees.  I've only been able to get abt 120 degrees, and its bugs me a bit.  Yet to take the xtal filter enclosure out of the receiver, and take it apart for repair, is more work than I want to do, especially where I can't think of any significant effect on receiver operation.

The Phasing control does seem to notch hetrodynes as advertised, so I think I'll leave that one discrepancy alone.

Thanks again.

-al hart

[Jim, W5JO]

Sounds like a good plan Al.  All you care about is it notching as much as possible.   It isn't worth the grief of removing that filter.  Just for grins, loosen C 36 a long way out then try carefully to set it.  Remember is doesn't take a lot to change that much.  That may help some.  If it doesn't your havent't lost anything

[KM1H]

I think it would be best if all your questions regarding one project are in one thread.

I agree, its one receiver, keep it all together. We dont have other rigs breaking into a dozen one liners.

While L-12 is for the mixer plate it does have an effect on filter alignment.

Carl