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just got an fm signal generator

mosteller

mosteller

Active Member
I am learning as I go here, and Ive had good instruction from an old electronics engineer who kinda took me under his wing. Im feel confident that ive grabed beyond the basics and so far have fixed 22 out of 22 vintage pieces. Anywhere from fisher tube receivers to monster pioneers and a mcintosh. Anyway I just bought a Heathkit FM Stereo Signal Generator IG-37 on the bay for 63 bucks and was wondering if anyone has had experience with this instrument and is it decent. I have a few tuners lying around and wanna get busy.
 
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Well, I'll share what I know. Alignment of AM radios is easy and straightforward, and can be done with a minimal amount of equipment. A signal generator and a good meter can get it done.

Alignment of FM radios is much more complex. Ideally you need a quality sweep generator and a good scope that covers at least the 10.7 MHz IF.

Alignment of Stereo FM Multiplex receivers, otoh, is really complex. Seriously. I couldn't begin to explain it coherently. There are a handful of AK'ers who do understand it, and most of them are the ones who do this professionally. It takes time and practice to get your head around both the concepts involved, and then the mechanics of going though the alignment processes. And, you need equipment that you know has been calibrated, or you're still shooting in the dark.

A few threads on basic FM alignment:

http://www.antiqueradios.com/forums/viewtopic.php?t=130054&highlight=alignment

http://www.antiqueradios.com/forums/viewtopic.php?t=118097&highlight=alignment

http://www.antiqueradios.com/forums/viewtopic.php?t=136995&highlight=multiplex

These are essentially about basic mono FM alignment. There is a lot of discussion about the equipment and how to use the equipment, which can be very helpful in understanding the processes involved.

If you don't have a pretty solid grounding in RF, it's kinda like drinking from a fire hose. And that's before you even start getting into Multiplex Stereo alignments. Voodoo.:yes:

Hope that helps. This is a lot more involved process than replacing old capacitors.
 
thanks, that is reassuring and encouraging. I'd say 75% of what I've done has been very involving....the rest , changing caps. I lucked up and made friends with an old navy electronics engineer who has takin me under his wing, so to speak. I myself being a Marine say, theres nothin to it but to do it....I got plenty of junk to try out my skills on. Anyway , there is probably alot of people out there without drive and determination (obsession)...lol, but someone had to start and learn somewhere.
Back to my question, does anyone know if the heathkit FM Stereo Signal Generator IG-37 is worth a crap for aligning FM?
 
mosteller said:
Back to my question, does anyone know if the heathkit FM Stereo Signal Generator IG-37 is worth a crap for aligning FM?
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I do own an IG-37. I am not an expert on FM alignment. I would not attempt to do a serious multiplex alignment using the IG-37. I would expect that if you did want to use your IG-37, a rebuild would be necessary.

I hope that other, more experienced members, will comment on specific FM stereo generators are really good for what you want to do.
 
mosteller,
could you update your findings on the Heathkit you bought? I have a chance to purchase one that is said to be functioning properly. Have you found yours to be an asset or a hindrance? I am trying to learn the basics on a budget, and I seem to be on a similar path as yours.

thanks,
David
 
David57 said:
mosteller,
could you update your findings on the Heathkit you bought? I have a chance to purchase one that is said to be functioning properly. Have you found yours to be an asset or a hindrance? I am trying to learn the basics on a budget, and I seem to be on a similar path as yours.

thanks,
David
Click to expand...

It works pretty good ...I had to change some caps in it, and calibrate the thing. Like everyone said , with the distortion involved and the 19 khz only at 100 , we will need a better one for multiplex. Other than that it seems to work good for everything else. And you would hardly ever have to use one anyway
 
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