I thought about it pretty hard, and did test the code. ?Worked as posted, makes a smooth transition when changing knob direction. ? A first cut, admittedly a bit inelegant. ??

The new code from my previous post does away with the constant flicker between adjacent frequencies due to noise in the ADC when the knob is not being rotated, but otherwise leaves functionality and feel exactly as Ashhar had coded it. ?Works on my Nano, I monitored the frequency value through the Arduino serial port. ?Remove the extraneous final 3 lines about the tone and replace them with a closing "}". ?(It was getting late.) ? The new code replaces this part of Ashhar's original code:

  // the tuning knob is at neither extremities, tune the signals as usual
  else if (knob != old_knob){
     frequency = baseTune + (50l * knob);
     old_knob = knob;
     setFrequency(frequency);
     updateDisplay();
  }

It works by inhibiting a reverse in direction of the tuning pot until that reversal has traveled through what would normally be 5 steps in frequency of 50hz each. ?For example, assume we have been tuning up in frequency and stop the knob at 7200.000 khz. ?A bit of noise comes in from the ADC, and the frequency pops up to 7200.050 khz. ?Another bit of noise comes in that would normally bring it back down to 7200.000 khz, but this is ignored because it does not reach the 5 tick threshold. ?A light touch on the knob might bring it a bit further up to 7200.100 khz. ?Reversing the direction of the knob, it travels through 5 steps before any change in frequency occurs, on the 6'th step the frequency goes back down to 7200.050 khz. ?If we leave the knob in that position, a bit of ADC noise might lower it further to 7200.000 khz, but noise will not raise the frequency. ?

I recommend operating with the original code at first until the noise at the pot has been evaluated and minimized with bypass caps and perhaps short shielded wiring. ?Then enable this new code by recompiling the sketch.

The frequency will still move a little bit after taking your hand off the knob, but can only move in one direction. ?If that is unacceptable but you otherwise like the current method of tuning, then perhaps reduce the tuning rate by a factor of two by replacing this line:

? ? ??frequency = baseTune + (50l * knob);

with this

frequency = baseTune + (50l * (knob>>1));

Jerry, KE7ER

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This is likely about as good as it gets: ??

A few minor changes:

? The two diodes D15 D16 are now a single BAT54S, so the balancing pot at R105 is not not needed or stuffed.

? ?No C103, no L4, all BC849's are actually MMBT3904's.

That should be pretty close. ?Are you seeing anything else?

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Thank you for the PNG files of the schematics.?? Do you have the mechanical layout of those two boards dimensions and hole sizes and hole mounting positions (x,y in milimeters)?? I am creating a http://LibreCAD.org drawing for a Metal Box Enclosure and want to create a drill holes for mounting the boards to the metal enclosure.? I do not have a Bitx40 Kit, to just directly measure the board and create the CAD Layout directly.?? Thank you for your help with outer dimension of the board, and the hole sizes and the hole pattern layout in a x,y format in milimeters (or inches).? Sarma vu3zmv

Board dimensions:? It’s a bit larger than some of my existing 40m homebrew transceivers at 128 x 114 mm for the main board.? Is this correct measurement?

See files here:

/g/BITX20/files/Enclosures_Metal_or_Plastic/Metal_Box_files/Metal%20Box%20Files

/g/BITX20/files/Enclosures_Metal_or_Plastic/Metal_Box_files/vu2xes_Aluminum_Case

Photos of Hand Made Aluminum Case:

Hello,

This email message is a notification to let you know that a file has been uploaded to the Files area of the [email protected] group.

File: lcd_Metalbox_bottom.dxf

Uploaded By: Fred Finster

Description:
LCD Metal Box Bottom Half Aluminum Box for Bitx40 case. Kiran VU2XES http://bitxhacks.blogspot.com/2017/02/vu2xes-cad-files-for-bitx-box.html Holds the LCD in the front with holes for microphone, headset audio, Encoder Knob, Volume Knob

You can access this file at the URL:
/g/BITX20/files/Enclosures_Metal_or_Plastic/Metal_Box_files/vu3psz_Aluminum_Case/lcd_Metalbox_bottom.dxf

Cheers,
The Groups.io Team

Gentlemen,

I have looked at a number of schematics but do not seem to find the one matching the current Bitx40 R3 transciever being sent from India.

Could someone please point me in the right direction or send a link to the correct file(s)

Tnx,

PJH, N7PXY

No Raduino here, but do have a Nano to play with. ?Here's a code scrap to replace that final clause in doTuning() to give the tuning pot a bit of hysterisis. ?Perhaps somebody could try it out.

  // the tuning knob is at neither extremities, tune the signals as usual
  else if (knob != old_knob){
    static char dir_knob;
    if ( (knob>old_knob) && ((dir_knob==1) || ((knob-old_knob) >5)) ||
         (knob<old_knob) && ((dir_knob==0) || ((old_knob-knob) >5)) )   {
       if (knob>old_knob) {
            dir_knob=1;
            frequency = baseTune + (50l * (knob-5));
       } else {
            dir_knob=0;
            frequency = baseTune + (50l * knob);
       }
       old_knob = knob;
       setFrequency(frequency);
       updateDisplay();
    }
o
   tone(CW_TONE, sideTone);
   tone(6, 1000);

Also, if you want a 1000hz square wave on pin 6 as a test signal, just execute this line somewhere:

? ? tone(6,1000);

That sets up a counter-timer to continuously generate the square wave while the Nano goes off and does other things.

Shut it down with

? ? noTone();

Jerry, KE7ER

Thanks very much for this, John.

For the record and/or posterity, I was unable to get a full 1A from HF Sigs' board #869.

I turned both R136 and RV1 fully clockwise, then opened RV1 until the Fluke 87 showed 100mA. ?(Amp input; meter on the A/mA setting)

R136 had to rotate almost fully CCW to get a solid 7W output power on the WM-2 Wattmeter. ?The PA was only drawing about 740mA at that point.

The IRF510's heatsink was warm to the touch, and the resting current draw was up to about 150mA. ?I turned RV1 a bit CW so the 'warm' current was 100 mA. ?Current with a strong 'ahhh' and a solid 7W out still shows about 740mA draw by the PA.

I'll have a CARE package from Mouser tomorrow - I'll get the signal on the o-scope on the dummy load and check the output signal then. ?In the mean time, I have a solid, intelligible signal on the SDR receiver now - thanks for that!