Thursday, April 2, 2015

A simple standalone antenna analyzer based on arduino and ad9850 with ili9341tft

ADVERTISEMENT
A simple swr analyser with ili9341tft and ad9850 dds

A simple antenna analyzer is a helpful gadget which will tell us about the frequencies to which a piece of wire will resonate on.  This is very useful in conjunction with a simple tuner to adjust the antenna for an optimum vswr (voltage standing waves ratio). Usually a good commercial antenna analyzer is an expensive device which we use once in a while. Here is a simple project which will give a rough estimation of vswr and resonant frequencies of random piece of wires, antennas and lc networks. For the critical reader, there is a lot of limitations with in this simple design and can read more about various possibilities here (keywords: harmonics, directional coupler, superheterodyne).

This project uses a simple ad9850 module as its heart to generate the rf signals for the sweep. The controller is an arduino promini (with an atmega328 running on 3.3volt) and for display, it uses an ili9341 tft.

The core circuitry for the analyser is very simple and is based on the design from Beriks (K6BEZ) simple antenna analyser (pdf). I added a buffer with the dds  (as shown on W5DOR).

To control the whole circuitry, i added an ir receiver which is useful for inputting frequencies, setting up the scan , span, etc. (basics on ir library). There is an updated version which uses a rotary encoder at the bottom of the page [Rotary Encoder]

So currently the firmware supports three things, a simple dds vfo, a vswr plot with sweep  from 1-30mhz and can be adjusted to smaller regions for e.g 7.000MHZ to 7.500 MHZ.

VSWR plot from arduino antenna analyser on a ili9341tft



There is a quick band scanner which scans all amateur radio bands and locate the best band which suits the antenna.


Scanning the bands
Simple dds function can be used to act as a signal generator for testing
Arduino DDS menu
Other future possibilities are to generate wspr signals. The circuitry is modular so that boards can be swapped to add extra functions and hence reusing the dds and tft display.

Here is a simple video of the analyser connected to an parallel lc circuit with a 50ohm carbon resistor to use it as a simple scalar network analyser (filter around 7mhz)



Here is some more pictures to show the constructions

DDS and controller together with display

buffer, opamp and detectors

building blocks

PC interface

Componets/modules

Finished assembly
Firmware is still basic and needs improvements. It can be downloaded from github. If you are building, the best way is to start in different stages as it involves several libraries. I would recommend the following sequence. It is a bit difficult for a beginner to get all this running at the first place. I will update a better writing at a later point with a compiled firmware so that it will be easier for a less experienced one to build it and calibrate.


  1. Get the arduino and lcd communicate and display the basic test patterns. See this post on getting the ili9341 up and running. It basically uses a simple library for drawing on the tft and i modified it a bit to get the correct display orientation (So use the ili9341 library here)
  2. Test the ad9850 module and the arduino to work together: See this post.
  3. Now get the Timed action, Infrared Remote and ad9850 libraries.
  4. Assemble the swr bridge board with buffer and adjust the potentiometer on the forward power to get a voltage output in the adc range (0-3.3v). Set the dds module to a fixed frequency and do the measurements (for e.g set 10mhz ) and do the same with a sweep. You could use the k6bez antenna analyzer script to test it first, which has the necessary functions to test and calibrate the circuit. See the link in the reference below (Note: adjust the sketch to match the pins (2,7,9,8)of your dds module)
  5. Upload the script and open a serial console. Keep pressing a remote control (any make) and assign the keys to different function by copying the number shown for specific buttons to the relevant areas in sketch.


A quick and dirty schematic (hand drawn) is attached below. It is basically derived from reference [1] and [3]. The construction used some simple pro-typing boards. RF sections could be better constructed on a copper clad in Manhattan style. Here i used a simple strip board and attached a ground plane with a conductive tape (separated by a plastic film).

Crude Schematic for the analyzer 
Rotary Encoder

Here  is a simple version of the vswr analyser using a rotary encoder with click. Connection is simple. Connect the center pin and one side of the click (button) to the ground. The other end of the click switch is connected to A0 pin and a library is used to detect single and double clicks (Onebutton). The other two pins on the encoder (of the three) is connected  to pin 2 and 3 of the arduino (interrupt). There is a slight change in the wiring for ad9850 dds module which is connected to pin 9,8,7 and 10. Backlight on the tft is directly connected to 3.3v via a current limiting resistor.

See this post for testing rotary and tft - Adding Rotary encoder to arduino projects- quick start


Connections

Attached a simple hand drawn block schematic for several modules. The vswr bridge circuitry is same as k6bez. Alternatively an ad8307 based rf sense circuitry can be used. Ensure that the output of the rf sense is adjusted to fall with in the adc range (here 0-3.3v). A 5v design needs a level shifter for the tft module.


Block schematic for the standalone analyzer with rotary encoder and Bluetooth serial (click to enlarge)
Additional Notes:

1) If running with a pro-mini on 3.3 volt, make sure that the fwd and rev voltages from detector falls wit in the adc range (0-3.3volt)

2) Buffer amplifier design is actually for 12 volt. I was running it at 5.5 volts  (make sure it is 5.5 with a multimeter, do not trust the wall wart) and got good results. To test it, add a 100 ohm resister to the antenna port and run the analyzer to get a flat line. If the swr rolles up at the higher frequencies, it means buffer is not working well. An alternative is to replace 1k resistors with 220 ohm and the emitter resister (470)with 220 for lower voltage. Also add an rf choke to the buffer power supply with a 0.1 cap to decouple.

3) Alternative solution is to run the promini at 5 volt and will give a wider adc (0-5v) at the cost of a level shifter.

4) Use a directional coupler to  replace the resistive bridge. Use an ad8307 log detector.

5) Adding a superheterodyne detector to get rid of harmonics  and drive the mixer  using a multiple clock generator (e.g Si5351) and use other channel to feed the sweeper/buffer.

Effect of inadequate power supply to buffer 

A few more pictures of the prototype in an earbud case :)



Hex File for atmega328 (Download)

Source Code (Download)


  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/*
A simple vswr analyser using atmega328, a resistive bridge and a diode detector 
Compared to my previous one, this is modified to support a rotory encoder
Usage: Single click on the encoder: Move across menu
Double click will select
Rotation is used to change the values
More: http://blog.riyas.org
*/
#include <stdint.h>
#include <TFTv2.h> //https://github.com/riyas-org/ili9341
#include <SPI.h>
#include <avr/eeprom.h>
#include <AH_AD9850.h> //http://www.arduino-projekte.de/index.php?n=7
#include <OneButton.h> //https://github.com/riyas-org/OneButton
#include <Rotary.h> //https://github.com/riyas-org/Rotary
#define SWR_STEP 64 //set it high for more points in the plot

Rotary r = Rotary(3, 2); // Encoder connected to interrupt pins 2 and 3 on arduino promini (atmega328)
OneButton button(A0,true);// Click button on the encoder the other end is connected to ground
AH_AD9850 AD9850(9, 8, 7, 10); //AH_AD9850(int CLK, int FQUP, int BitData, int RESET);

// Pins for Fwd/Rev detectors
const int REV_ANALOG_PIN = A2;
const int FWD_ANALOG_PIN = A1;
//const int EXTRA_ANALOG_PIN = A3; // an extra detector for rf power 

const byte lcdW = 320 ;
const byte lcdH = 240 ;
const byte fontWidth = 10 ;
const byte fontHeigth = 30 ;
const byte totSpan = 9;
float spanValue[totSpan] =
{
    25000.0, 50000.0,100000.0, 250000.0,500000.0, 1000000.0, 2500000.0, 5000000.0,10000000.0
}
;
byte SWR[SWR_STEP];
//byte PWR[SWR_STEP];
float minSwr;
float maxSwr;
uint32_t next_state_sweep = 0;
byte menu_redraw_required = 0;
byte doubleClicked = 0;
byte modSpan = 0;
byte posInput = 0;
byte sign = 0; // negative
float Swr ;
float Pwr ;
struct settings_t
{
    int spanIdx;
    float freqCenter;
}
settings;
//averaged analogue read slow but solid
double analog_read_value(int pin) {
    double total = 0.0;
    double reading;
    int i;
    for (i=0; i< 80; i++) {
        reading = analogReadX(pin);
        total += reading * reading;
    }
    return total / 80.0;
}
double analogReadX(const int pin)
{
    if (pin==FWD_ANALOG_PIN) //in my case forward reading has an offset
    return analogRead(pin);
    else
    return analogRead(pin)-17;
}
void Docalcswr(){
    double FWD=0;
    double REV=0;
    double VSWR;
    // Read the forawrd and reverse voltages
    REV = analog_read_value(REV_ANALOG_PIN);
    FWD = analog_read_value(FWD_ANALOG_PIN);
    if(REV >= FWD){
        // To avoid a divide by zero or negative VSWR then set to max 999
        VSWR = 999;
        } else {
        // Calculate VSWR
        VSWR = (FWD+REV)/(FWD-REV);
        // Rx=(25+REV)/(0.5*FWD-REV-0.5);
        Swr = abs(VSWR);
       // Pwr = sqrt(analog_read_value(EXTRA_ANALOG_PIN));
    }
}
void creaGrid()
{
    byte p0 = lcdH - 2;
    for (int i = 0 ;i < 9; i++)
    {
        Tft.drawVerticalLine((i*40),fontHeigth,164,RED); //240*320
    }
    for (int i = 1 ;i < 2; i++)
    {
        Tft.drawHorizontalLine(0,i*82+fontHeigth,319,RED); //240
    }
    Tft.drawCircle(160,164+fontHeigth,5,GREEN);
    if (settings.freqCenter >9999999)
    Tft.drawFloat(settings.freqCenter/1000000,130,214,2,YELLOW);
    else
    Tft.drawFloat(settings.freqCenter/1000000,130,214,2,YELLOW);
    float s = spanValue[settings.spanIdx]/8;
    for (int i = 0 ;i < 9; i++)
    {
        double freq = (settings.freqCenter + (i-4)*s)/1000000;
        Tft.drawFloat(freq,(i*40),185,1,YELLOW);
    }
    if (spanValue[settings.spanIdx] >9999999)
    Tft.drawFloat(spanValue[settings.spanIdx]/1000000,260,214,2,YELLOW);
    else
    Tft.drawFloat(spanValue[settings.spanIdx]/1000000,260,214,2,YELLOW);
    Tft.drawRectangle(0,fontHeigth,320,164, GREEN);
    Tft.drawString("SWR",0,0,2,CYAN);
    Tft.drawFloat(minSwr,40,0,2,GREEN);
    Tft.drawFloat(maxSwr,120, 0,2,RED);
    if (!modSpan)
    {
        Tft.fillRectangle(40,210, 60,20, CYAN);
        Tft.drawString("freq",40, 210 ,2,BLUE);
        Tft.drawString("span",210, 210 ,2,BLUE);
    }
    else
    {
        Tft.fillRectangle(210,210, 50,20, CYAN);
        Tft.drawString("freq",40, 210 ,2,BLUE);
        Tft.drawString("span",210, 210 ,2,BLUE);
    }
}
void printSwr()
{
    for (int k = 0;k < SWR_STEP; k++)
    {
        int spacer=320/SWR_STEP;
        Tft.drawLine(k*spacer,SWR[k],(k+1)*spacer,SWR[k+1],WHITE); //plot vswr
        //Tft.drawLine(k*spacer,PWR[k],(k+1)*spacer,PWR[k+1],GREEN); //plot power
    }
}
void showCursor(int x0, int y0)
{
    Tft.fillRectangle(x0,y0, 50,8, BRIGHT_RED);
}
void draw(void)
{
    Tft.fillRectangle(0, 0, 320, 240, BLACK);
    creaGrid();
    printSwr();
    if (doubleClicked == 1)
    {
        switch (modSpan)
        {
            case 0 :
            {
                if (posInput <3) posInput = 3; showCursor(130,235);
                break;
            }
            case 1 :
            {
                posInput = 6;
                showCursor(260,235);
                break;
            }
            default: break;
        }
    }
}
void setup(void)
{
    Tft.TFTinit(); // init TFT library
    Tft.fillRectangle(0, 0, 320, 240, BLACK);
    analogReference(DEFAULT);
    // initialize serial communication at 9600 bits per second:
    Serial.begin(9600);
    //rotory interrupt
    PCICR |= (1 << PCIE2);
    PCMSK2 |= (1 << PCINT18) | (1 << PCINT19);
    sei();
    //set up the click on the encoder
    button.attachDoubleClick(doubleclick);
    button.attachClick(singleclick);
    eeprom_read_block((void*)&settings, (void*)0, sizeof(settings));
    if (settings.freqCenter <= 0)
    {
        settings.freqCenter = 7000000.0;
    }
    settings.spanIdx = 8;
    //settings.freqCenter = 7000000.0;
    AD9850.reset(); //reset module
    delay(200);
    AD9850.powerDown(); //set signal output to LOW
    AD9850.set_frequency(0,0,settings.freqCenter);
}
void calcParameters(int k, float stepSpan)
{
    float freq;
    float tempSwr;
    //float tempPwr;
    freq = settings.freqCenter + (k-SWR_STEP/2)* stepSpan;
    if (freq <= 0) freq = 1000000.0;
    AD9850.set_frequency(freq);
    delay(1);
    Docalcswr();
    Swr = max(1.00,Swr);
    //Pwr= max(1.00,Pwr);
    //tempPwr= min (600, Pwr);
    //Serial.print("temppwr:");
    //Serial.println(tempPwr);
    minSwr = min(minSwr,Swr);
    maxSwr = max(maxSwr,Swr);
    tempSwr = min (3.0, Swr);
    SWR[k] = 30+(164 - round(82*(tempSwr - 1))); //MAX SWR = 3.0 164+fontHeigth
    //PWR[k] = 30+(164 - round(164*((tempPwr*tempPwr)/360000))); //Pwr;
}
uint8_t update_graph(void)
{
    Tft.fillRectangle(250, 0, 70, 20, BLUE);
    Tft.drawNumber(next_state_sweep,250,0,2,CYAN);
    if ( next_state_sweep < SWR_STEP)
    {
        if(next_state_sweep == 0)
        {
            minSwr = 10.00;
            maxSwr = 1.00;
        }
        float s = spanValue[settings.spanIdx]/SWR_STEP;
        calcParameters(next_state_sweep,s);
        next_state_sweep++;
        return 0;
    }
    else
    {
        next_state_sweep = 0;
        return 1;
    }
}
float updateFreq(double r, float v)
{
    float step = round(pow(10,posInput));
    if (r == DIR_NONE )
    {
        // do nothing
    }
    else if ((r == DIR_CW) && (v + spanValue[settings.spanIdx]/2 < 54000000.0))
    {
        v = v + step;
    }
    else if ((r == DIR_CCW) && (v >= step + 1000000.0))
    {
        v = v - step;
    }
    return v;
}
void updateSpan(double r)
{
    if (r == DIR_NONE )
    {
        // do nothing
    }
    else if (r == DIR_CW)
    {
        settings.spanIdx++;
    }
    else if (r == DIR_CCW)
    {
        settings.spanIdx--;
        if (settings.spanIdx < 0) settings.spanIdx = totSpan -1;
    }
    settings.spanIdx = settings.spanIdx % totSpan;
}
void routine(void)
{
    if ( update_graph() != 0 | menu_redraw_required != 0)
    {
        draw();
    }
    menu_redraw_required = 0; // menu updated, reset redraw flag
}
void loop()
{
    // keep watching the push button:
    button.tick();
    routine();
}
ISR(PCINT2_vect) {
    //Serial.println("interrupt");
    unsigned char result = r.process();
    if (doubleClicked)
    {
        if(modSpan){
            updateSpan(result);
        }
        else
        {
            settings.freqCenter = updateFreq(result, settings.freqCenter);
        }
    }
    else modSpan = !modSpan;
    menu_redraw_required = 1;
}
void singleclick()
{
    //change position in field
    //Serial.println("Single");
    if (doubleClicked)
    {
        posInput++;
        posInput = posInput % 7;
    }
    menu_redraw_required = 1;
}
void doubleclick()
{
    //change field
    //Serial.println("double");
    doubleClicked = !doubleClicked;
    if (!doubleClicked) eeprom_write_block((const void*)&settings, (void*)0, sizeof(settings));;
    menu_redraw_required = 1;
}


Simple schematic for analyser with encoder


Here is a simple attempt to draw a schematic in eagle cad. If some one can help out with a nicer one, please drop an email or comment

Schematic for the analyser with encoder


Partlist
Part Value Package Description
C1 1u C050-025X075 CAPACITOR, European symbol
C7 1u C050-025X075 CAPACITOR, European symbol
C8 100n C050-025X075 CAPACITOR, European symbol
C9 10n C050-025X075 CAPACITOR, European symbol
C10 100n C050-025X075 CAPACITOR, European symbol
C11 10n C050-025X075 CAPACITOR, European symbol
D3 AA143 DO204-10 DIODE
D4 AA143 DO204-10 DIODE
IC2 LM358N DIL08 OP AMP also LM158; LM258; LM2904
PROMINI3.3VOLT PRO-MINI-2 PRO-MINI-2 Arduino Pro Mini Layout 2
R1 470 V234/12 RESISTOR, European symbol
R2 1k V234/12 RESISTOR, European symbol
R3 100 V234/12 RESISTOR, European symbol
R4 5k V234/12 RESISTOR, European symbol
R12 50 V234/12 RESISTOR, European symbol
R13 50 V234/12 RESISTOR, European symbol
R14 50 V234/12 RESISTOR, European symbol
R15 50 V234/12 RESISTOR, European symbol
R16 100k V234/12 RESISTOR, European symbol
R17 5k V234/12 RESISTOR, European symbol
R18 648 V234/12 RESISTOR, European symbol
R19 10k V234/12 RESISTOR, European symbol
R20 100k RDH/15 RESISTOR, European symbol
R21 5k V234/12 RESISTOR, European symbol
R22 648 V234/12 RESISTOR, European symbol
R23 47 V234/12 RESISTOR, European symbol
SW1 EC12E_SW ALPS_EC12E_SW ALPS rotary Encoder EC12E series with switch
T2 2N2222 TO18 NPN TRANSISTOR
T3 2N2222 TO18 NPN TRANSISTOR
U$2 2.2_TFT_LCD 2.2_TFT_LCD
U1 AD9850 DDS Module DDS_AD9850 AD9850 DDS Module
X2 BNC AMP_227161 JACK, RIGHT ANGLE, 50 OHM, PCB, BNC


References

[1]  http://www.hamstack.com/hs_projects/k6bez_antenna_analyzer.pdf

[2]  http://iphone-atom1945.blogspot.com/2013/08/antenna-analyzer-arduino-uno-dds-ad8307.html

[3]  http://www.zl2pd.com/digitalZmeter.html

[4] https://github.com/devzendo/antenna-analyser-c

55 comments:

  1. Can you publish a PartList an athe Arduino Source?

    73 de Christian

    ReplyDelete
    Replies
    1. I will soon be updating it on github. AA143 was a bit difficult to get , but i guess a good alternate solution is to use an ad8307 for rf detection.
      Other important parts were
      1) Arduino promini (from ebay)
      2) ili9341 tft display
      3) TSOP 1738 ir receiver
      4) Any ir remote
      5) Stripboard and connectors
      6) LM324,2n2222 assorted resistors and caps
      7) AD9850 dds module from ebay

      73s

      Delete
  2. Replies
    1. an error : antenna_light_tft.ino: In function 'void showCursor(int, int)':
      antenna_light_tft.ino:176:36: error: 'BRIGHT_RED' was not declared in this scope

      Delete
    2. You need the library for the ili9341. It is available from gmtii on github. (See the previous post to get the display working ie getting started with ili9341)

      Delete
    3. Colour? Can you send a picture?

      Delete
    4. It seems the orientation of the display is wrong, so you are missing a part of the swr chart. Now i remember i modded somewhere in the library to get it in landscape. I will update it on github/ will mail you.
      Best regards

      Delete
  3. Replies
    1. https://github.com/riyas-org/ili9341

      Delete
    2. This is great stuff...

      Hi, I faced the same issue as the wrong orientation issue.. could you edit yr original documents above links to point them to the modded ili9341 library instead...

      Delete
    3. Thanks Stanley! updated

      Delete
    4. Hi Riya,

      I am trying your code for encoder use and so far so good. I am not able to find any updated code that will allow the display to display landscape rather than portrait. The analyzer .ino I am using is the version shown on this page.

      Am I missing something (most likely!) and can you point me in the right direction?

      Thanks & 73's
      Mark - WT6P

      Delete
    5. Hi Mark, use the mdified tft library from my github: https://github.com/riyas-org/ili9341
      73s
      Riyas

      Delete
  4. Dear Riya,

    Firstly, you did a great job combining them together to make this 2.2" antenna analyzer...

    I've setup the circuit on the breadboard...

    I've a few thing that I do not understand... hope you can enlighten me..

    1. Using yr current sketch, when I probe various point with an osciloscope, the output freq is constant at 125Mhz ..

    Which function in the code are for setting the freq sweep ?

    2. What are the IR buttons for ?
    singleclick ?
    doubleclick ?
    longclick ?
    centerset ?


    3. I didn't see the "quick band scanner" screen ? Was it disabled in the current codes posted on github..

    4. How do I set the 10k POT in A0 ? How do I calibrate it ??
    I usually put a 50ohm terminator at the end of a bnc plug ...

    ReplyDelete
    Replies
    1. Thanks for the comments. See update_graph_band(void) which does the sweep for bands and see void calcParameters(int k, float stepSpan), which does sweep for the chart. If you look closer at the function void calcParameters(int k, float stepSpan), you can see that the array SWR[] getting filled and will then gets plotted. I recommend you to upload the sketch from K6BEZ in the beginning to calibrate the analyser. I will detail it here when i get some more time.

      It seems your dds is not getting the control signals. Try using AD9850.set_frequency(freq); in the set up to see if dds works fine

      IR buttons are not fixed. You have to manually assign them with the ir codes. Basically the longclick will cycle through the different options ie VSWR chart mode, Band mode and DDS mode. Double click will cycle through the menu and single click will increment/decrement values. Centerset was used for a debug where it set the maximum scan range when the analyser is in swr charting mode.

      Calibration is same as K6BEZ analyser. Put the terminator and adjust for minimum swr. In the beginning make sure that the voltage variation is in the adc range. I used analogReference(DEFAULT); but you can think of other possibilities here.

      I know this post is a fast and dirty one even for an expert home brewer. These days am very busy with several other boring things and sadly missing the hobby and blog. Once things are settled, i will try to make a better discription and i want to upgrade it with a logarithmic rf detector from analog devices (cheap and easy to calibrate)

      Delete
    2. Thanks for the lengthy reply...

      For yr circuit, what are the use of the 0.1uF caps before the SWR bridge ??

      Without the 0.1uF caps, I'm getting almost 3V but with it, the voltage are too low to trigger the 1N34 diode that I am using...

      I noticed other SWR bridge circuit also have this caps there ?

      Was it to removed the DC biased voltages ???

      Delete
    3. i also think the same about 0.1 ( coupling and dc filter). I borrowed it from other designs. I found in34 to behave a bit strangely while AA143 works smoothly. Have a look at http://www.njqrp.org/digitalhomebrewing/breadboard/issue4-SWR.html where they use a compensation for in34 (an extra stage with an opamp with 1n34 which compensates for the nonlinearities in the diode detectors). Alternatively we can use ad8307

      Delete
  5. This comment has been removed by the author.

    ReplyDelete
    Replies
    1. hi, when i am compiling I am getting linked errors of header files.WProg.h,math.h(roundoff),,LPC17xx,contneus errors.can any one tried,please respond

      Delete
    2. AVGR
      You need to open up the Timed Action file in an editor and change "Wprogram.h" to "Arduino.h"
      Save and recompile. I had the same problem and this fixed it.

      Delete
  6. Hello
    I really like this project and I am trying to get it all ruinning for a possible club project here in St. Louis.
    So far I have the TFT, Arduino, Remote and DDS card all operating.
    I cannot seem to get it to change modes. I can change the freq. and span but I can't get it to go into the other modes. I have changed all the IRRemote numbers in the code to correspond to my remote but get no response from the 'longclick " button.
    Any ideas??
    It seems that maybe some code is missing to get it to enter into the other routines once the remote button is sensed.
    Larry

    ReplyDelete
  7. Found the problem in the firmware.
    Changed this line from; select_display = select_display++; to; select_display =++ select_display;
    Now it cycles through the three MODES.
    Larry
    n0sa

    ReplyDelete
  8. Hi all.
    I am having trouble in compiling this sketch. I think I have all the libraries installed correctly, but it is still throwing these errors at me. I don't have good understanding what error messages mean, but usually can get sketches to run. Any help would be great.
    Arduino: 1.0.6 (Windows 7), Board: "Arduino Nano w/ ATmega328"
    In file included from C:\Program Files (x86)\Arduino\libraries\TimedAction/TimedAction.h:33,
    from antenna_light_tft.ino:14:
    C:\Program Files (x86)\Arduino\libraries\TimedAction/WProgram.h:20: error: default argument given for parameter 3 of 'long unsigned int pulseIn(uint8_t, uint8_t, long unsigned int)'
    C:\Program Files (x86)\Arduino\libraries\TimedAction/wiring.h:119: error: after previous specification in 'long unsigned int pulseIn(uint8_t, uint8_t, long unsigned int)'
    C:\Program Files (x86)\Arduino\libraries\TimedAction/WProgram.h:22: error: default argument given for parameter 3 of 'void tone(uint8_t, unsigned int, long unsigned int)'
    C:\Program Files (x86)\Arduino\hardware\arduino\cores\arduino/Arduino.h:224: error: after previous specification in 'void tone(uint8_t, unsigned int, long unsigned int)'

    Any help would be great.

    Peter
    VK2YYO

    ReplyDelete
    Replies
    1. Hi Peter,

      please check: http://playground.arduino.cc/Code/TimedAction

      This library is used to get rid of a blocking behaviour from the infrared library. A rotory encoder can be used to get rid of the ir remote and this library and i will try to update it whne i get more time

      73s

      Riyas

      Delete
  9. Hi Riyas,

    I have enjoyed this project greatly, but have run into a couple issues I am hoping to get some assistance with. I am using an UNO and the AD9850 with TFT. I have not modified the original analyzer sketch.

    These are the current errors and I am at a loss to find the issue:

    Arduino: 1.6.6 (Windows Vista), Board: "Arduino/Genuino Uno"

    antenna_light_tft:28: error: 'infrared' was not declared in this scope

    TimedAction timedAction = TimedAction(100,infrared);

    ^

    antenna_light_tft:29: error: 'routine' was not declared in this scope

    TimedAction timedAction2 = TimedAction(100,routine);

    ^

    exit status 1
    'infrared' was not declared in this scope

    Also, I was wondering if/when you may present the encoder version, rather than the IR version. Thanks for your hard work...Great project!
    Mark - WT6P

    ReplyDelete
    Replies
    1. Hi Mark, thanks for the comments. Exactly now am working on it (its lying on the table) a cleaner version with the encoder which will make it a lot simpler. The ir version need a clean up with a direct input of start and end frequency with number of steps. Please check the Timedaction library (http://playground.arduino.cc/Code/TimedAction)which is used to get the ir remote working without blocking the rest of the code. Please wait a weak or two and will replace it with encoder.

      73s
      lb7ug/Riyas

      Delete
    2. Oh Riyas, that is fantastic! I will check out the TimedAction library and see what I can find out. It has been a while since I have programmed in C (have been tied up with HTML for years!) and it is slowly coming back to me.

      I look forward to your revised analyzer, that is exciting.

      Tks, 73
      Mark - WT6P

      Delete
  10. Any Info now about this project final version

    Igor Derivolov Z32ID

    ReplyDelete
  11. Hello, Riyas. I built your antenna analyser, but frequency shows 0.00. I don´t know what is happening. 73. Marcos.

    ReplyDelete
    Replies
    1. Try uncommenting line 191 in setup code.(settings.freqCenter = 7000000) 73s Riyas

      Delete
    2. After send you a message i founded it...Many tanks.

      Delete
  12. Riyas, i need some help:

    At lines 61 and 66 appears AnalogReadX and when i remove X my TFT only flash.

    In time, what´s the procedure to add scanning bands mode and DDS signal generator?

    73.

    ReplyDelete
    Replies
    1. Good find. AnalogueReadX is used to correct for small offset in readings. The code for band and dds is there in my github. But it is still crude and will update with a better version when i get time. Also the code needs some more optimization to make the plotting and screen refresh faster. 73s

      Delete
  13. Hi RiYa
    i only got white screen and erratic output from ad9850 when all connected up.
    put a 1k resistor from vcc to reset on tft screen and a 1k from ground to reset on ad9850 now working fine,hope this will help.(rotary version).
    73 stan(g8ihc)

    ReplyDelete
    Replies
    1. Hi RiYa.
      I am having trouble in compiling this sketch.

      https://i.imgsafe.org/695e2b7.jpg

      73! Daniel

      Delete
    2. Hi Daniel,

      You have 2 options:
      1. Please upgrade your project to the ARDUINO 1.6.5 version. The problem will disappear because the new compiler supports const class members.
      2. remove the line 59 "const int _debounceTicks ..." in the OneButton.h file and define it as a global constant using a pre-compiler directive:
      #define _debounceTicks 50
      in OneButton.h before the class definition (line 25)

      Delete
  14. Hi RiYa, I love this project (encoder version). I made some improvements to the design and software.
    1. Added a 5V to 12V converter to provide 12V power the transistor buffer.
    2. Starting at line 104, changed:
    (a) center frequency position & display to 3 decimal places for adjusting 1Khz.
    (b) Added to the display, after center frequency the posInput variable to make it easier know what frequency step is being adjusted (6=1Mhz,5=100Khz,4=10Khz & 3=1Khz)
    Code:
    104 Tft.drawFloat(settings.freqCenter / 1000000, 3, 75, 214, 2, YELLOW);
    Tft.drawNumber(posInput, 160, 214, 2, GREEN); //6=1Mhz,5=100Khz,4=10Khz & 3=1Khz
    }
    else
    {
    Tft.drawFloat(settings.freqCenter / 1000000, 3, 75, 214, 2, YELLOW);
    Tft.drawNumber(posInput, 160, 214, 2, GREEN); //6=1Mhz,5=100Khz,4=10Khz & 3=1Khz

    This a great cheap analyzer that I used to successfully tune all my antennas.

    thanks for this post
    jerry

    ReplyDelete
    Replies
    1. Hi Jerry, Just curious here, I deleted line 104,105,106, replace with

      Tft.drawFloat(settings.freqCenter / 1000000, 3, 75, 214, 2, YELLOW);
      Tft.drawNumber(posInput, 160, 214, 2, GREEN); //6=1Mhz,5=100Khz,4=10Khz & 3=1Khz
      }
      else
      {
      Tft.drawFloat(settings.freqCenter / 1000000, 3, 75, 214, 2, YELLOW);
      Tft.drawNumber(posInput, 160, 214, 2, GREEN); //6=1Mhz,5=100Khz,4=10Khz & 3=1Khz

      and can't compile, I get error message as below:

      expected unqualified-id before 'else'
      expected unqualified-id before 'else'

      Please help ??

      Delete
    2. Oh OK, I found the problem. there're missing curly brace at the beginning and at the end. problem solved. thanks !

      Delete
  15. Hello!Thank you for the project!I'm trying to run it on the Board Arduino UNO.For some reason I have nothing is working, only white screen.I have connected all pins like in the diagram,only UNO,in what could be the problem?

    ReplyDelete
    Replies
    1. You are welcome. Make sure lcd is compatible with 5 volt !! I guess your uno is running at 5v and the display needs 3.3 volt. Need to use a level shifter. I have tested with a 3.3 volt on uno a while ago (no guarantee on this approach). Just feed uno's vcc pin with 3.3v and do not power it by usb.

      Delete
  16. Thanks for the great information covered here.
    I have been working with the analyzer at VK3YY and wanted to upgrade to a TFT display - this web has been very helpful. I see you have a pot to set the swr bridge in the setup - 4. Assemble the swr bridge board with buffer and adjust the potentiometer on the forward power to get a voltage output in the adc range (0-3.3v).

    However I dont see anywhere on the schematic where there is a pot shown. I think it would be either R12 or R13 is that correct? Regards Terry M VK4ATM

    ReplyDelete
    Replies
    1. Thanks Terry for your feedback. I used to write the posts in a hurry so i always miss something. The pot is not on the bridge( the bridge should use exactly 50 ohms except a very small correction if you need to adjust for the capacitance of the antenna connectors used ).

      The out put from the bridge goes to two OPAMPS (it could be lm324 as in my hand drawn circuit on top of this page or LM358 as in the eagle schematic at the bottom of the page with encoder). This opamps has a variable resistor (10K) connected between its output pins and inverting input pin(4 and 13 for lm324) and a resistor (648 ohm)connected to ground from the inverting input (those -ve marks on opamp). The 10 kilo ohm variable resistor is placed over there and will adjust the gain of that opamp.

      There are two opamps used and they will multiply the small voltage from the bridge to a broader range for better read in the atmega328/microcontrollers adc. See http://mustcalculate.com/electronics/noninvertingopamp.php to get an idea on how these resistor and gain works.

      An other important thing is if these opamps are run at higher than 5volts, the output may goe above 5 volts which can damage the adc of microcontroller. So keep it under 5v.

      73s de lb7ug

      Delete
    2. Thanks for the info. I have at last been back to this project. The Tft display I purchased lead me on a real chase to get the drivers to work and then to modify the code to suit the altered tft board. Yes it was one of the cheap boards from ebay and I had to change the names to suit the adafruit-tft driver that works with this board.

      A query within the code is used the tft.float variable. I have worked out how to substitute or change almost all other variable wording differences in the code but cant figure out what that variable does. Can you shed some light on that?

      Delete
    3. You are welcome! If you are refering to Tft.drawFloat function, which is used to write a number with decimals in to the tft screen.

      For e.g : Tft.drawFloat(settings.freqCenter/1000000,130,214,2,YELLOW);

      This will write the center frequency on tft (at location 130,214) with a font size 2 and color YELLOW). So you can replace with some similar function and basically you need to write a float value to screen

      So you could use the analyser with for e.g ucg library with some modifications. I used the above code to save some memory to add more features as other libraries took more space on the micro-controller.

      I hope this helps.

      Delete
  17. Nice project, I'm trying to make it. The part with the Arduino and the display works already. I use a larger display, a 2.8 inch ili9341 and it works perfectly.
    Now I'm trying to draw a PCB for the measuring-bridge and the AD9850.
    In the diagram the value from R18 and R22 is ¨648¨, what do you mean by that? This is 680 ohms or 680 k?
    And in the diagram, i think R15 will have to be 10k instead of 50 ohms.

    Regards, Janbert.

    ReplyDelete
  18. Thanks Janbert. It is in ohms and 680ohm will be fine. The other one is 10k ohm (input to opamp). Regards

    ReplyDelete
  19. Hi RiYa,

    Nice analyzer ! just wish to know if you're using Arduino 3.3V/8Mhz ? or normal 5V/16Mhz version of Arduino but operate at 3.3V?

    ReplyDelete
    Replies
    1. 3.3v,at 8mhz, also make sure adc voltage wont go above this

      Delete
    2. Thanks! sure , will adjust the ADC voltage carefully .

      Delete