I've been aligning radios by ear with limited success, and I now realize that I need to get more precise to get the best performance from my restoration projects. Here's the question. I have an EICO 324 signal generator. I need to know if the frequency counter on a Radio Shack model 22-811 digital multimeter is sufficiently accurate to calibrate the signal generator for alignment purposes?

Hi Leon,

I do not know the answer to your question but would like to share my experience with signal generators.

I also have an EICO 324 signal generator and had a similar problem in that the frequency indicated by the dail was not very accurate. This made radio alignment difficult, especially for the short wave bands. This presented a problem. I could not afford to buy an expensive frequency counter so how could I accurately set the frequency on my signal generator?

To solve this problem I was fortunate enough to be able to borrow a good frequency counter. I used it to take readings from each band of the EICO 324. For example, frequency readings were taken on Band A with the linear scale dial set at 10, 20, 30 and so on up to 100. This process was repeated for the remaining bands.

For example, here is the data from Band B:
DIAL SETTING - FREQ(MHz)
10 - 0.419616, 20 - 0.461167, 30 - 0.514440,
40 - 0.584247, 50 - 0.673381, 60 - 0.773426,
70 - 0.887531, 80 - 1.010190, 90 - 1.143640,
100 - 1.244240

Now the fun part, using Excel and a curve fitting program, a polynomial curve was fit to each set of dial/frequency data.

Using the polynomial equations, I set up an Excel program that calcultes the dial setting required for any frequency. All I do is enter the desired frequency and the program tells me the required dial setting.

Using this program I can now set my EICO 324 to ANY frequency, accurate to less than 1%, without a frequency counter! Actually, when I verified the program the setting accuracy was closer to 0.1%.

I also calibrated my Precision E-200-C and obtained similar results.

If anyone would like to see what I did just give me your email address and I will send you the Excel file.

Also, I would be happy to provide anyone who is interesed, a calibration program for your signal generator. Just supply me the frequency vs linear dial setting data.

Gary

:I've been aligning radios by ear with limited success, and I now realize that I need to get more precise to get the best performance from my restoration projects. Here's the question. I have an EICO 324 signal generator. I need to know if the frequency counter on a Radio Shack model 22-811 digital multimeter is sufficiently accurate to calibrate the signal generator for alignment purposes?

Here a quick way to check the low end of your signal genertor. Tune an AM radio to a broadcast station operating at a known freq. Then adjust your 324 with a modulated signal, until the tone is smack on top of the broadcast station.