Si5351B 127mhz<not working<150mhz about si5351arduino HOT 6 OPEN

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I made the connections with the Si5351BCBreakout.pdf file. I'm using demo sketch. I've tried changing frequencies. I see the signal at 127mhz. But no signal between 128-149mhz. And I received the signal again on 150mhz.

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https://nt7s.com/2019/06/regarding-recent-availability/

from si5351arduino.

Hi,
Can I add to this issue that for me (SI-5351A-B-TG) the same problem occurs ?
When running an oscillator.ini which does not use any libray but writes to the registers I can have it put a carrier on 144.490 MHz.

When running wspr tracker on either Atmega328p or ESP8266 with this library and set to:
#define WSPR_FREQ 144490550UL // 2 mtr

It does not output on the wanted frequency. Monitoring the spectrum on an SDR shows that it transmits, I see signal on 140.772 MHz but with wider shift as default for wspr so that might be a harmonic from a lower frequency.

Tested all HF wspr frequencies up to 10 mtr whick works okay.

from si5351arduino.

I hope you find the time to take a look at this issue. Still no luck to get it to work at 144 MHz.

Thanks,
Ben

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@zanco @NT7S

I had the same issue.

It seems div by 4 needs to be activated from 125 MHz upward and not 150 MHz. But when doing so, for 125 MHz the PLL frequency would be 500 MHz. Since the library does not support such a low PLL all frequencies between 125 and 150 MHz are changed to 150 MHz.

So a setting that works but is out of specs is

#define SI5351_PLL_VCO_MIN 500000000
#define SI5351_MULTISYNTH_DIVBY4_FREQ 125000000

I would also point that Si5351 is supposed to go down to 2.5 KHz from revision 1.0 and that OMD can go to 2048, se personally I have these settings, working, provided there isn't a bug I haven't seen:

#define SI5351_MULTISYNTH_A_MAX 2048

#define SI5351_MULTISYNTH_MIN_FREQ 320000
#define SI5351_CLKOUT_MIN_FREQ 2500

these two parameters must be set together, it would be best to have

#define SI5351_MULTISYNTH_MIN_FREQ SI5351_CLKOUT_MIN_FREQ * 128

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