Adding a SWR function to BITX40

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beamin

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I was reading through the code and saw this:
/**
* Display Routines
* These two display routines print a line of characters to the upper and lower lines of the 16x2 display
*/

void printLine1(char *c){
if (strcmp(c, printBuff)){
lcd.setCursor(0, 0);
lcd.print(c);
strcpy(printBuff, c);
count++;
}
}

void printLine2(char *c){
lcd.setCursor(0, 1);
lcd.print(c);
}

/**
* Building upon the previous two functions,
* update Display paints the first line as per current state of the radio
*
* At present, we are not using the second line. YOu could add a CW decoder or SWR/Signal strength
* indicator




How would you add a SWR function to the second line? This would be very handy since i make my own antennas!
 

Kb2Jpd

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May 6, 2016
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Location
New York City, NY
I was reading through the code and saw this:

/**

* Display Routines

* These two display routines print a line of characters to the upper and lower lines of the 16x2 display

*/



void printLine1(char *c){

if (strcmp(c, printBuff)){

lcd.setCursor(0, 0);

lcd.print(c);

strcpy(printBuff, c);

count++;

}

}



void printLine2(char *c){

lcd.setCursor(0, 1);

lcd.print(c);

}



/**

* Building upon the previous two functions,

* update Display paints the first line as per current state of the radio

*

* At present, we are not using the second line. YOu could add a CW decoder or SWR/Signal strength

* indicator









How would you add a SWR function to the second line? This would be very handy since i make my own antennas!


Start here: http://www.na0tc.org/lib/exe/fetch.php?media=technical:homebrew_swr_meter.pdf

I would design the circuit just for reflected power back, not SWR. Tune your tuner or prune your antenna for minimum reflected power and you are good.

All you need is a ADC (analogue to digital convertor) and some way for it to be read by the microcontroller running the display.


Sent from my iPhone using Tapatalk
 

beamin

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Messages
108
So this is the circuit you add?
BITX Hacks

Im legally blind so im having a bit of trouble finding the code and parts list.
 

beamin

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Jan 27, 2012
Messages
108
i forgot to add Im really new to arduino and electronics so that first example seems a "bit " over my head.

But I did figure out how to build a power supply from scratch as well as the antenna.
 

Kb2Jpd

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Joined
May 6, 2016
Messages
207
Location
New York City, NY
So this is the circuit you add?

BITX Hacks



Im legally blind so im having a bit of trouble finding the code and parts list.


Then your solution is a simple one.

I worked with Dan Kb2Mlh with making audible SWR/Power meters for him. He is also a blind ham. I used to make a circuit called a Voltage Controlled Oscillator and connect the circuit across the meter movement.

Tuned it for lowest SWR. The circuit I used in the past was a 555 connected to a speaker and the power switch was a mercury switch. You tilted the meter upward, you did the tune, then rested back down and the circuitry would shut off.

http://www.learningaboutelectronics...d-oscillator-VCO-circuit-with-a-555-timer.php

Maybe it's time for that circuit to make a reprise.




Sent from my iPhone using Tapatalk
 
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