No reason for it, it's just another bug that needs to be squashed.
On Tuesday, April 8th, 2025 at 11:51 AM, K9HZ <bill@...> wrote:
¡°The math under the hood in the frequency calibration routine doesn't account for the fine tune frequency offset.¡±
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I didn¡¯t catch that either¡ any reason for that. Seems a bit quirky¡
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Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ
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Owner - Operator
Big Signal Ranch ¨C K9ZC
Staunton, Illinois
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Owner ¨C Operator
Villa Grand Piton ¨C J68HZ
Soufriere, St. Lucia W.I.
Rent it:
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Moderator: North American QRO Group at Groups.IO.
Moderator: Amateur Radio Builders Group at Groups.IO.
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email:? bill@...
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Are you saying that if you tune to 10 MHz and select SAM demodulation, you measure a frequency offset of 190 Hz?
A gotcha with the frequency calibration is that it matters how you tune to 10 MHz -- don't touch the fine tune knob! The math under the hood in the frequency calibration routine doesn't account for the fine tune frequency offset. Instead, tune by pressing the Dir Freq (Direct Frequency) button and entering 10 on the button pad. Does that help?
On Monday, April 7th, 2025 at 8:35 PM, epif18 via groups.io <epif18@...> wrote:
I'm running a V12, 66.9, TCXO.? I've run freq cal and I'm off by 190 hz.? I've hard coded the cal value into si5351.init as well as 0.0.? The 190 hz error shows against my freq standard (10MHz) as well as my Siglent sig gen.? Zero beat is at 10,000,190. And when I'm listening to some SSB net on 20M, the best audio comes in at +190 hz (assuming they run the net on a whole freq).? Freq cal shows an error of 0.15Hz throughout the 20 min.? I adjust the cal factor to a freq error of 0.15Hz before I start cal.? I've run cal multiple time with the same results.? Everything is temp stabilized.
190 Hz isn't that bad but I'd like it to be close to zero.
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