There’s a very simple way to check the calibration of your rig, using WWV and a laptop computer running a digital modes program. First, connect the rig audio to the computer. At home, I connect the line output of my IC-746PRO to the mic input of my laptop. At WA2HOM, we use a SignaLink USB to connect the rig’s line output to our desktop computer.
Next, set your radio to one of the WWV frequencies. Here in Michigan, we receive WWV best on 10 MHz, so that’s the frequency that I use. On my IC-746PRO, I set the receive frequency to 10.000.00 MHz, using the keypad.
Now, fire up the digital modes program and observe the waterfall display on the laptop. WWV broadcasts standard frequency audio tones that alternate during most minutes of the hour. Most minutes feature a 500 Hz audio tone (minutes 4, 6, 12, 16, 20, 22, 24, 26, 28, 32, 34, 36, 38, 40, 42, 52, 54, 56, 58) or 600 Hz audio tone (minutes 1, 3, 5, 7, 11, 13, 17, 19, 21, 23, 25, 27, 31, 33, 35, 37, 39, 41, 53, 55, 57), but note that during some minutes, there is no audio tone.
This tone should be easily discernible on the waterfall display, and the closer it is to 500 Hz or 600 Hz, depending on which tone is being broadcast, the closer your rig is to being properly calibrated. I do this every month or so, just to make sure that my radio hasn’t drifted.
For more information on the WWV transmissions, go to Information Transmitted by WWV and WWVH.
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