Re: memory manager/alignment


Gordon Gibby
 

This is the kind of system that I used to calibrate my V3 so long ago.   Once you measure the exact frequency, which was typically about 3 kHz off, you just put that frequency into the software and re-compile.   Bingo!   

It’s been a long while since I did it, but that’s such an easy way to do things.  


On Oct 19, 2020, at 14:23, AndyH <awhecker@...> wrote:

Mitchel,

   I found the crystal measurement routine I use - it's a very short sketch from ND6T from Feb, 2017.  As we only need the actual crystal frequency for this part of the cal, this does exactly what we want.  it sets the Raduino to output a 25 MHz signal on the clock 2 line.  Let it run 20 or 30 minutes until temperatures stabilize, then measure the clock 2 output with a counter.  That number goes into the firmware for the actual 25 MHz crystal frequency.

   OM Cantrell's code follows - it's 20 lines.  Source:  http://www.nd6t.com/bitx/Calibration.htm

/*
 Calibration program for Raduino
 Don Cantrell,ND6T  v 1.1          8, Feb 2017
 Compiles under Si535 library v 2.0.1
 This source file is under General Public License version 3.
 Generates the reference clock frequency so that it can be 
 measured and substituted as the corrected frequency of the
 particular oscillator. 
 */
#include <si5351.h>
Si5351 si5351;
 
void setup() {
    
    si5351.init(SI5351_CRYSTAL_LOAD_8PF,25e6L,0); 
    si5351.set_pll(SI5351_PLL_FIXED, SI5351_PLLA);
    si5351.set_freq(25e8 , SI5351_CLK2); 
}
void loop() {
}

    73, Andy

On Fri, Oct 16, 2020 at 11:38 AM, Mitchel Rought wrote:
is it possible to change the display frequency through memory manager, after alignment this radio is slightly off, web sdr 7.050.000, this radio 7.049.700, I realize it's not much but still bothers me

Join BITX20@groups.io to automatically receive all group messages.