[regel_1999]

I got my AA5 working. With a 25' antenna strung through my living room (something my wife 'loves' <sarcasm>) I can pick up all the local stations. I tried to align the radio based by messing with the radio until I got some stations, but then I went to look up how to 'actually' align it and I've found out I should have a signal generator and an oscilliscope, along with some other tools. I don't have these, so is it fine that I just align this set by ear?

What I've done is set the knob to a strong, local station and then aligned the RF stage and then the IF stage independently to make the radio sound strongest there. The rest of the local stations come in okay and the shortwave works (even with the 25' antenna - although I know I should have ~50 feet of antenna for good sw). The only problem is the bottom of the band, from maybe 550am to ~ 650am doesn't come in clearly and shortwave from about 9m to ~ 10m doesn't seem to pick up anything. I've tried to adjust it and all that happens is I lose everything!

Anyone have any ideas or suggestions that don't require oscilliscopes or signal generators?

thanks in advance!
-Brandon

[Ron Ramirez]

You will find people who will say it is fine. However, I'm not one of them.

If you want to be serious about this hobby, you will invest in a little bit of test equipment and learn how to use them.

An analog multimeter is cheaper than a scope and will work quite nicely as an output indicator. However, there is no substitute for a good signal generator.

If you want your radios to operate at peak efficiency, you'll align them correctly using the proper equipment.

I noticed another Phorum member, Ed Locker, had replied to one of your posts and offered to help you out. He isn't too far from you, as I understand. He is very knowledgeable in tube circuits - he works as a TV repairman, so he knows his stuff. It would be worth your while to let him teach you a few tricks of the trade.

Perhaps you could even ask him to align your sets for you if you give him a little $$. Just a thought.

[regel_1999]

Hey Ron,

Thanks. I was afraid you'd say that, but then again, I was pretty certain the answer to my question before I asked...

I guess I know what I'm asking my wife for for my birthday and christmas

I'll try to get a hold of Ed. He offered to help me out a few weeks ago, but I haven't had a chance to make the drive to his place.

I guess one last thing: is there a good place to get a signal generator and/or oscilloscope that's not too expensive?

Thanks for everything and I'll try to get some pictures here in the next week of my radios!

-Brandon

[Radioroslyn]

Just took a quick look and saw this on epay
http://cgi.ebay.com/200589211775
This is the same model I use. Pretty simple unit. Price seems good so far.
Terry

[nash]

As others have said, it is possible, but better results are had with a signal generator and a meter monitoring the AVC voltage.

Your radio is deaf on the lower part of the dial due to the tracking being off. Typically this is due to the IF being tuned to the wrong frequency. Most IF cans will happily peak anywhere from about 400 to 500KHz. Unless the IF is set to what the radio needs (typically 455KHz) the sensitivity will suffer on the lower part of the dial. Some sets allow adjustments than can peak the lower and upper parts of the dial, but then the middle of the band will be deaf if the IF is not 455KHz.

By ear, you can try to correct the IF frequency. This is done by tuning to a weak station at the bottom of the band, under 600KHz if possible. Now you have to "walk" the IF peak, and the tuning dial in steps for best reception. Try tuning below the station until you just hear it, then peak the IF. If reception improves, walk it lower and try again. If reception is worse, walk it higher and try again. You will reach a point of best reception with the IF peaked after a few steps. If you go too far, the reception will get worse again. Walking the tuning and IF for best reception retunes the IF frequency closer to 455KHz. The process is much faster and more exact with a signal generator. If you have a meter, watch the AVC voltage as it is easier to see the change than hear it.

Once the IF is tuned, then go to a station around 1400Khz and adjust the antenna trimmer capacitor for best reception. Now note the frequency of the station on the dial. If it is not what the station frequency really is, then adjust the oscillator trimmer as you walk the dial to the correct reading. After the dial reads correctly, repeak the antenna trimmer. These trimmers are typically on the tuning capacitor on an AA5 set.

Now check out the set across the dial, hopefully it tracks well now and receives well up and down the dial.

The shortwave section often has a antenna padder or coil to adjust for the bottom of the dial, and a trimmer for the upper part, as well as for the oscillator. I would not adjust the oscillator settings until you get a signal generator as it is rather easy to fubar the alignment and end up with no reception on shortwave.

[exray]

Adding to the noise A while back on a different forum someone posted a very good, albeit lengthy, tutorial about how to sneak by without springing for $20-30 on a signal generator. Like Nash indicates, the first step is to get the IF to the correct frequency or else you're just shooting in the dark. The tutorial explained how to tune in a station and then listen on a second radio to observe if the local oscillator signal could be heard 455 kc higher on radio #2. If you understand the fundamentals of a superhet you can see how this can work but its probably bad advice to a first-timer.

Its easier to spring for a signal generator. Nowadays with digital radios available for next to nothing a fellow can take a cheapo hobby generator and calibrate it well with a few pencil marks on the dial! Probably better calibration than the old radiomen had at their disposal.

And...the nature of the old beasts is that some of them (the cheap home radios) don't track that well anymore and I sometimes wonder if they ever did? BTW, the term " tracking" refers to the relationship between the RF section and local oscillator section...not just where the signal appears on the dial. Sometimes its a compromise.

[regel_1999]

Interesting idea to use another radio to align the antique with. I wonder why I didn't try that before. I should give it a try. I know this radio isn't tracking quite right (mostly because station 820am comes in clearly at ~570am on the dial and at the lower end of the dial I just get a steady buzz). However, other than the numbers being off and the inability to listen to the lowest parts of the dial, I can at least get what 'I' want, which is NPR on 820am, even if it is slightly off.

I'll definately keep the radio-to-radio alignment in thought as I finish up my philco. I've got two capacitors on order, the dial plate at the print shop, and the decals en route from tubes & more. I've resoldered the wires that were in really bad shape, recapped all but the electrolytics (which are the ones on orders) and checked the resistors (which read within ~15% of their rated values). The tubes, at least preliminarily, appear good. So hopefully I'll get this sucker put together and we'll see how it works...

-Brandon

[w4rtc]

Hi all I just have to say this!!!! I never could get my ear into those little adjustment holes and if I could I would get dizzy going around and around turning the adjustment screw . I would use a generator I don't think you can align a radio correct without one. See yea. Joe