The PHILCO Phorum
FM alignment - Printable Version

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FM alignment - Eric Adams - 08-25-2013

I've been getting a lot more FM radios lately and I do an alignment per instructions, but I know I'm missing something. Do some of you have a sweep generator for FM alignments? I'm thinking of getting one but I don't know what to look for. Can you guys give me an idea?
Is this the kind of generator that can be used? http://www.ebay.com/itm/BK-Precision-Function-Sweep-Generator-Model-4003A-/181200670347?pt=LH_DefaultDomain_0&hash=item2a3066ce8b

Thanks

RE: FM alignment - Mondial - 08-25-2013

No Eric, that generator won't work for FM alignment, It is a low freq sweep/ function generator, not an RF sweep generator.

This is the kind of sweep generator I use for FM alignment. The HP 8601A is a great quality generator that covers up to 110 Mhz. They can sometimes be found on ebay for less than $100 and is well worth the money. This listing is a bit pricier but it gives an idea of what it looks like:

http://www.ebay.com/itm/Agilent-HP-8601A-Generator-Sweeper-1-110-MHZ-5977-/261265151254?pt=LH_DefaultDomain_0&hash=item3cd49dd516

RE: FM alignment - Eric Adams - 08-25-2013

Thanks for pointing me in the right direction, Mondial. I think I've got an idea of what to look for.

RE: FM alignment - Eric Adams - 08-25-2013

Mondial, would this work? http://www.ebay.com/itm/HP-HEWLETT-PACKARD-AGILENT-694C-PORTABLE-BENCHTOP-SWEEP-OSCILLATOR-RF-GENERATOR-/330997149876?pt=LH_DefaultDomain_0&hash=item4d10f7b0b4

RE: FM alignment - Mondial - 08-25-2013

No good. That one covers 8000 to 12400 MHz !

The HP 8620C is also a possibility but you need to make sure it has the low freq 1- 110 MHz plug in.

I would still recommend the 8601A. It is not only a sweep generator but also a calibrated output AM-FM signal generator, adjustable from 0.1 microvolt to 3 volts of RF output.

RE: FM alignment - Eric Adams - 08-25-2013

So that's all I'd need for all alignments? That's what I'll go after, thanks.

RE: FM alignment - Mondial - 08-25-2013

Yes, the 8601A would be the only generator you would need for any FM radio alignment. It will also work for AM and shortwave alignment, but it may not go down low enough to align low freq IF's, so it would still be good to have an inexpensive AM RF generator on hand.

Here is a link to the service and operation manual, so you can get an idea of what it can do:

http://bama.edebris.com/download/hp/8601a/HP%208601A.pdf

RE: FM alignment - codefox1 - 08-25-2013

Whatever, pretty reliable inexpensive frequency counters are available to check the accuracy of aging signal generators, which always benefit from a recap/recarb job and should be left on for at least a half hour to stabilize, and of course be very careful about grounding. I have changed a lot of such old test stuff to 3 prong plugs and know my bench is wired properly. I do use isolation transformers where appropriate, so it's been a while since I was last knocked on my **s.

RE: FM alignment - Eric Adams - 08-26-2013

Thanks a lot, Mondial. I'll read up on it first before I pull the trigger.

RE: FM alignment - Eric Adams - 08-27-2013

Ok Mondial, What about this one:
http://www.ebay.com/itm/HP-HEWLETT-PACKARD-AGILENT-694C-PORTABLE-BENCHTOP-SWEEP-OSCILLATOR-RF-GENERATOR-/330997149876?pt=LH_DefaultDomain_0&hash=item4d10f7b0b4

RE: FM alignment - BrendaAnnD - 08-27-2013

That's the same one you posted before. It's for microwave work.

RE: FM alignment - Eric Adams - 08-27-2013

oops! How about this one:http://www.ebay.com/itm/261273162211?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649


Thanks

RE: FM alignment - exray - 08-27-2013

Eric, if you are doing plain-jane AM/FM restorations of simple sets from the 40s and 50s you can get by without a sweeper. The alignment is pretty simple.
I've done it both ways. And I stay out of modern circuits - haha.

RE: FM alignment - Eric Adams - 08-27-2013

I know what you mean, exray and please don't take offence, but I'm not a "get by" kinda guy. I like to dig in and learn as much as I can. So now that I've mastered AM alignments I want to be able to do a complete FM alignment.

Thanks

RE: FM alignment - exray - 08-27-2013

Maybe I should back up and say aligning a 1947 Philco FM radio is quite a different study than aligning a 1979 Sansui stereo receiver. Its indeed not a "get by" thing on modern radios. Totally different disciplines. Just didn't know where you were 'coming from' in the original post.