Title: SI5351 and OVI40
Post by: Co on 04. January 2021, 15:33:50
Hello to all,
I have a spare populated OVI40 ui-board for which I made frontend with a 'potato' mixer and a SI5351 oscillator with 2 outputs and 90 degr. phase shift. Presently the SI5351 is controlled with a teensy.
The IQ output is fed to OVI40 ui-board. It works quite well.
Question: How do I activate the SI5351 routines available in the OVI40 software? recompile?
Kind regards and a prosperous (and above all a healthy) 2021.
Co |
Title: Re:SI5351 and OVI40
Post by: DF8OE on 04. January 2021, 16:08:33
Hi Co,
SI5351 is autodetected - no recompilation neccessary. But you need additional parts (divider by 4) if you want to work on lower bands starting from 160m. SI5351 is not able to produce quadrature output at frequencies below ~2,5MHz...
vy 73
Andreas |
Title: Re:SI5351 and OVI40
Post by: Co on 05. January 2021, 15:37:58
Hello Andreas,
Tnx for your response. Unfortunately I am using a 25 Mhz xtal for the SI5351. So it will have to wait until the 27 Mhz xtal arrives.
Kind regrds
Co |
Title: Re:SI5351 and OVI40
Post by: DF8OE on 05. January 2021, 16:35:39
Yes - 27MHz is mandatory...
vy 73
Andreas |
Title: Re:SI5351 and OVI40
Post by: Co on 17. January 2021, 15:34:37
Hello Andreas,
In the mean time installed a 27Mhz xtal. All works nicely . The vfo covers even 50 and 70 Mhz. The SI5351 is however in need of calibration. On 3.5 Mhz the deviation is approx. 100 Hz. Is the calibration option, as per the configuration menu, also implemented for the SI5351 ?
Kind regards
Co |
Title: Re:SI5351 and OVI40
Post by: DF8OE on 17. January 2021, 18:12:32
It does not matter what oscillator is in use. Calibration is a facor which is thrown on the frequency that sohuld be tuned.
vy 73
Andreas |
Title: Re:SI5351 and OVI40
Post by: Co on 17. January 2021, 19:09:12
Andreas,
That is clear. The reference correction is applied when the PLL frequency is being calculated which is performed next to the calculation of the multisynth divider values. In this calculation (specifically the PLL) the 27 Mhz crystal comes into play. So eventual deviation of the xtal from 27 Mhz. should be corrected by a fixed value.
For the SI570 this is done via the callibration (debug settings). Does this apply also to the SI5351 ?
Regards
Co |
Title: Re:SI5351 and OVI40
Post by: DB4PLE on 17. January 2021, 19:23:00
Hi,
follow the procedure outline here to calibrate:
https://github.com/df8oe/UHSDR/wiki/Adjustment-and-Configuration-Manual#frequency-calibration
The frequency calibration works, as Andreas wrote, regardless of oscillator used.
The relevant entry is not in the debug menu, but in the config menu, though.
BTW, I have no clue what debug menu entry you are referring to.
73
Danilo
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Title: Re:SI5351 and OVI40
Post by: Co on 18. January 2021, 12:36:47
Hi Danilo, Andreas,
You were quite right. The callibration as per the configuration menu works excellent and works for both SI570 and SI5351. I referred to a method often used for the SI5351 i.e. correcting the deviation of the reference xtal.
Kind regards
Co
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