Rather than drag out my signal generator and frequency counter, here's a quick and dirty way to align the oscillator and the IF of an AM receiver.

I have a Degen DE1103 multi-band, solid-state portable radio (about $45, plus $20 shipping from China http://stores.ebay.com/V-COM-COLLECTIONS ). I can tune it accurately on the AM broadcast band to 1kHz, and can precisely pinpoint the frequency of another radio's oscillator.

For example, tune the antique radio to a known station, say 1000kHz. If I pick up the oscillator freq on the DE1103 at, say, 1438kHz, then it is generating an IF of 1438-1000 = 438kHz. If the IF is supposed to be 455kHz, adjust the oscillator trimmer to bring the oscillator up to 1455kHz.

Then adjust the IF xfmr trimmers for peak volume.

All done in about 5 minutes.

When using the DE1103 to listen for the other radio's oscillator, it's best to select the single-sideband mode, so you hear a whistle. Tune the DE1103 for the center of the whistle, where the tone is lowest. Once you've located the oscillator, turn off the antique radio and make sure the whistle disappears; if it doesn't disappear, you're probably hearing an internal birdie of the DE1103.

Hi Doug

A good idea. Signal generator & frequency counter.

Here is something else that can be done if someone hasn't messed with IF Transformers. Align the radio using oscillator and antenna trimmers first. After these are set just peak up IF Transformers by ear.

Norm

:Rather than drag out my signal generator and frequency counter, here's a quick and dirty way to align the oscillator and the IF of an AM receiver.
:
:I have a Degen DE1103 multi-band, solid-state portable radio (about $45, plus $20 shipping from China http://stores.ebay.com/V-COM-COLLECTIONS ). I can tune it accurately on the AM broadcast band to 1kHz, and can precisely pinpoint the frequency of another radio's oscillator.
:
:For example, tune the antique radio to a known station, say 1000kHz. If I pick up the oscillator freq on the DE1103 at, say, 1438kHz, then it is generating an IF of 1438-1000 = 438kHz. If the IF is supposed to be 455kHz, adjust the oscillator trimmer to bring the oscillator up to 1455kHz.
:
:Then adjust the IF xfmr trimmers for peak volume.
:
:All done in about 5 minutes.
:
:When using the DE1103 to listen for the other radio's oscillator, it's best to select the single-sideband mode, so you hear a whistle. Tune the DE1103 for the center of the whistle, where the tone is lowest. Once you've located the oscillator, turn off the antique radio and make sure the whistle disappears; if it doesn't disappear, you're probably hearing an internal birdie of the DE1103.

Nice little digital readout radio.

My signal generator and freq counter are always right there above my bench... So I don't have to "drag" them out. ( Can't imaging where else I'd keep them?)

But I too do sort of the same thing Doug ...depending on my mood.

I have a probe connected to my freq counter and I place it near the local oscillator. Then I tune to the strong local 770khz station until it's right on. Then I look to see if the oscillator is running at 1225khz and adj if necessary. Then I go peak the IFs... couple minuets too.

Peter: good deal. What kind of freq counter do you have?

My freq counter is a massive HP 5252A, Nixie tube display, etc. Plenty of precison, but its sensitiviy, about 0.1V, won't reliably pick up RF. I have to connect it electrically to the oscillator ckt. That takes time and the connection might change the oscillator freq slightly?

:Nice little digital readout radio.
:
:My signal generator and freq counter are always right there above my bench... So I don't have to "drag" them out. ( Can't imaging where else I'd keep them?)
:
:But I too do sort of the same thing Doug ...depending on my mood.
:
:I have a probe connected to my freq counter and I place it near the local oscillator. Then I tune to the strong local 770khz station until it's right on. Then I look to see if the oscillator is running at 1225khz and adj if necessary. Then I go peak the IFs... couple minuets too.

I kind of like Doug's method. Seeing as I drag out the digital radio anyway..... I have to because my signal generator isn't that accurate...don't know why. It's an EICO of some sort with the bright aluminum panel. It's never that far off, but I want things perfect because I'm a perfectionist. I could just align the radio by ear, which I used to do before I purchased a generator, but I want everything just right....so I use a digital radio to align the generator, and then I use the generator to align the radio. Guess I could just eliminate the generator step and stick with the digital radio. It's one of those Seacrane or whatever the name is. Picks up stations all the way from 100 KC to about 30 MC, and then FM.

T.

Doug:
My freq counter is a GW freq counter - Model GFC8010G
I've never heard of it before but it's real nice and small too. (approx 2" high by 7" wide by 8" deep)
Has several sensitivity and gate ranges and can read from as low as 5-hz up to 120-mhz
... and the best part is that I bought it on Ebay for only about $30 used.
Works great!
Here's one recently on Ebay:

http://cgi.ebay.com/INSTEK-FREQUECY-COUNTER-MOD-GFC-8010G_W0QQitemZ150018429839QQcmdZViewItem

:Nice little digital readout radio.
:
:My signal generator and freq counter are always right there above my bench... So I don't have to "drag" them out. ( Can't imaging where else I'd keep them?)
:
:But I too do sort of the same thing Doug ...depending on my mood.
:
:I have a probe connected to my freq counter and I place it near the local oscillator. Then I tune to the strong local 770khz station until it's right on. Then I look to see if the oscillator is running at 1225khz and adj if necessary. Then I go peak the IFs... couple minuets too.
:
Will those methods cover from low to high end reception consistency? Since local OSC can generate desire freq. by either by trimmer cap or coil adjusment. Thanks for your advice.

Hi, Duke. Most simple radios have just a trimmer on the oscillator section of the variable tuner - no padder for the low end. Most have fixed oscillator coils.

But yes, you can adjust the oscillator freq at any point on the dial. At the low end, for example, tune a station at 540kHz, and adjust oscillator for 540 + IF. At high end, tune a station at 1600kHz and adjust the oscillator for 1600 + IF.

If you just have a trimmer, no padder, then the whole IF offset adjustment will move more or less across the whole band. You can try to split the difference by adjusting the oscillator freq in the middle of the band.

::
:Will those methods cover from low to high end reception consistency? Since local OSC can generate desire freq. by either by trimmer cap or coil adjusment. Thanks for your advice.

Thanks for your clear explanation.
:Hi, Duke. Most simple radios have just a trimmer on the oscillator section of the variable tuner - no padder for the low end. Most have fixed oscillator coils.
:
:But yes, you can adjust the oscillator freq at any point on the dial. At the low end, for example, tune a station at 540kHz, and adjust oscillator for 540 + IF. At high end, tune a station at 1600kHz and adjust the oscillator for 1600 + IF.
:
:If you just have a trimmer, no padder, then the whole IF offset adjustment will move more or less across the whole band. You can try to split the difference by adjusting the oscillator freq in the middle of the band.
:
:
:::
::Will those methods cover from low to high end reception consistency? Since local OSC can generate desire freq. by either by trimmer cap or coil adjusment. Thanks for your advice.

I probably mislead you about the oscillator trimmer. It will affect the high-end alignment, but not much at all at the low end. So use the trimmer to adjust the oscillator for a station toward the high end. Without a padder, then you'd just live with the tracking across toward the low end, but it shouldn't be too big an issue.

:Thanks for your clear explanation.
::Hi, Duke. Most simple radios have just a trimmer on the oscillator section of the variable tuner - no padder for the low end. Most have fixed oscillator coils.
::
::But yes, you can adjust the oscillator freq at any point on the dial. At the low end, for example, tune a station at 540kHz, and adjust oscillator for 540 + IF. At high end, tune a station at 1600kHz and adjust the oscillator for 1600 + IF.
::
::If you just have a trimmer, no padder, then the whole IF offset adjustment will move more or less across the whole band. You can try to split the difference by adjusting the oscillator freq in the middle of the band.

:I probably mislead you about the oscillator trimmer. It will affect the high-end alignment, but not much at all at the low end. So use the trimmer to adjust the oscillator for a station toward the high end. Without a padder, then you'd just live with the tracking across toward the low end, but it shouldn't be too big an issue.
:
::Thanks for your clear explanation.
:::Hi, Duke. Most simple radios have just a trimmer on the oscillator section of the variable tuner - no padder for the low end. Most have fixed oscillator coils.
:::
:::But yes, you can adjust the oscillator freq at any point on the dial. At the low end, for example, tune a station at 540kHz, and adjust oscillator for 540 + IF. At high end, tune a station at 1600kHz and adjust the oscillator for 1600 + IF.
:::
:::If you just have a trimmer, no padder, then the whole IF offset adjustment will move more or less across the whole band. You can try to split the difference by adjusting the oscillator freq in the middle of the band.
:
Doug,

On some later radios, the oscillator coil had an adjustable ferrite core which could be adjusted for better performance around 600Kc.

Radiodoc