Don,
I would recommend doing a full calibration.? The steps for a v6 are in this video:
The same steps would apply to the v3:
1 - First, adjust the BFO using the BFO tuning aid
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? ? ?This allows the lowest frequencies to be heard/detected by the beating in the next step.
2 - Calibrate against an AM station or a signal generator you know to be accurate.? One of the WWV stations is good.? Higher frequencies will give more accurate results.? I use a 10MHz frequency standard for my calibrations.? I bought one like this:
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? ? ?with an attenuator.
3 - Adjust the BFO to center the plateau between the red bars on the BFO tuning page.
The difference from the v6 is how you get to the settings.? You do so for v5 and earlier by turning on the Setup option in the menu.? You need to also power cycle the uBitx after saving the value to ensure that the saved value is being used.? Remember to write down and save the values for each step if you want to return to a prior value.? Note that the stock software does not display the current value when the calibration step is turned on.
There is a difference with the stock v5 firmware in that it sends a 10MHz CW signal that can be measured with a frequency counter.? AFAIK this is true for only the v5 stock software.
If you use a signal generator, adjust or attenuate the level below 1 millivolt to prevent damage to the uBitx.? Adjust up or down from that value if needed.
73
Evan
AC9TU
