I have no idea what the various software releases for the uBitx are doing.
But during calibration, the BFO should be placed in the center of the 12mhz crystal filter?
so a zero beat can be heard.
Also, the accuracy of that zero beat is proportional to the frequency of the signal.
So a zero beat to WWV at 15mhz is 15 times more accurate than a zero beat of a 1.0mhz AM broadcast station.
The three local oscillators are each a strict ratio of the 25mhz reference,? ?and from post 44515
the operating frequency of a stock uBitx in LSB mode is:? ? vfo - (clk1-bfo)?
By the distributive law of algebra, a 100ppm change in vfo, clk1 and bfo will result in a 100ppm change in the operating frequency.
Jerry
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On Tue, May 29, 2018 at 03:38 pm, Glenn Anderson wrote:
When tuning in an AM station when your rig is listening on SSB, you will hear a carrier tone... This will vary depending on whether you change your frequency up or down... When you tune so that the frequency you hear gets so low that it "disappears" then you have "zero-beated" on the station... Most commercial rigs have a tune button that typically is at every 25 or 100 khz on the dial...
Once you no longer hear the tone then that's when you calibrate your dial... A good frequency on air is WWV @ 10.000Mhz...
I hope that helps,
Glenn VE3JAU
