Radio Direction Finding

[PA3BNX]

Hello Every Body,

I post here a picture of the
classic 4 monopole or 4 dipole FM rx mode antenna array

and the Plate Antenna (4 directions) AM rx mode.

Both antenna types can work on the Arduino Shield

for my SuperSimpleArduinoDoppler direction finder

[Mark-02660]

Nice Work!   

I have always wanted to do this.  I was going to make the interface with HTML5 and do all the processing on a micro controller since I dont do windows programing!   

Have you got it all working yet?

And videos of it in action?

[Melt-O-Tronic]

Thanks for your persistence on this topic, PA3BNX.   

I've been following this forever and am learning a lot.  I've read a ton of info and visited dozens of web sites, but I think this thread has been one of the most useful resources in my own experimentation.  Your diligence is very much appreciated.  RDF is a very intriguing aspect of amateur radio to me.

[PA3BNX]

Hello Every Body,

I am working on an elevation display next to the arduino terminal and pelorus display
for the SuperSimpleArduinoDoppler
running in MyMapping1.57

I did extended the agrelo protocol %123  with
two brackets and in between the dopplertone amplitude like [12]

So this has no influence on other agrelo fields.

Ofcourse the arduino uno doppler software must be extended with the []

See the picture


The doppler tone amplitude depends on the elevation
So low above ground much doppler amplitude
en high just above you no doppler tone amplitude anymore.

This works ofcourse not with  AM with the plate antenna.

Bug found
CW/CCW doesn't work yet with the plate AM antenna.

I try to fix that to in the next software arduino.ino release.

New version software is not yet released.

[PA3BNX]

Hello Every Body,

Yes I got it all working

Stil there is always things to improve.

I was also thinking of writing a simple PelorusDisplay program  in Python
that reads the data through USB arduino.

I have not yet done that...

It would be nice if we could connect the arduino doppler on a tablet or smart phone hi..

So anybody who want or can write it...

The Arduino Uno is very nice with a USB and then display on a smart phone through blue tooth ?

[PA3BNX]

Hello Every Body,

I did again some updates in the Arduino SuperSimpleArduinoDoppler Sketch

The last version had a bug in MultiPathDetect in the Average Function

And now the CW/CCW with the max232 and the AM plate antenna works too

You must rename I think the file to Arduino4.txt to Arduino4.ino

for the Arduino IDE

Have fun Guys/Girls

[PA3BNX]

Hello EveryBody,


I  added an analogue meter Pelorus readout on the arduino doppler project.

So I connected an analog meter about 100 to 400uA with a 10 k series resistor
and a series 10k potmeter on pin6 arduino (must be a PWM pin value 0-255 0> 4.5V)

Now with the new software I have a readout on the meter of

180-270-0-90-180 degrees voor homming in in the car.

(Draw a new scale paper and glue it in the meter)

I also use the standard led13 on board of arduino uno r3 now for
squelch indicator open/closed.

You can leave the refpa3bnx circuit connected like I did

Ony set in the arduino source

const bAnalogPelorus = true;

If you would use a cheap audio VU meter from scrap equipment you
may correct the liniarity of that meter with a function in AnalogPelorus ?

I did not do that yet.

The meter is a nice cheap help for homming in while driving in a car.

Oh the calibration and CW/CCW and Averaging does stil work and can be adjusted through the
terminal software or MyMapping ofcourse.

So have fun experimenting.

New source code in arduino.txt attachment.

[PA3BNX]

Hello Every Body,


Some things from TCI you should see :

TCI youtube demo



https://www.youtube.com/watch?feature=player_detailpage&v=EJlSurZZh44
https://www.youtube.com/watch?feature=player_detailpage&v=elOZo3I-W6o
HF RDF
https://www.youtube.com/watch?feature=player_detailpage&v=H8UXhyHgpm0

Wow hi..

[PA3BNX]

Hello Every Body,

Now working on a LM3914 10x led homming in Pelorus for the arduino doppler.

The lm3914 doesn't show  a burning led if the input voltage is 0 Volts.

So I have to fiddle a bit with offset in the AnalogPelorus Function in the

Arduino Source.

Circuit draws about 10mA at 5V so can be fed from the USB

[PA3BNX]

Hello Every Body.


I did n't think of the fact that an arduino PWM pin does give two voltage levels instead of a DC signal.
(about 500 Hz switching)

So the lm3914 Pelorus lit just two leds hi ...

The fix was replace the input level potmeter with one of 47k and acros the wiper and mass a elco of 1uF

Now it works okay hi

Also changed a little bit the Arduino source

All Pelorus leds are of if squelched.


Now it also has a test mode press T in terminal so first and last led light for 5 seconds.

You can have the doppler rotation frequency simultaniously
if you mount 2 diodes on oin2 and 3 to the lowpass input circuit.

See new arduino shield circuit drawing.


To nice youtubes with dopplers:

Doppler autotrack quadcopter
https://www.youtube.com/watch?feature=player_detailpage&v=SqWVdhSeA6A
TSCM DDF2020T

[PA3BNX]

Hello Every Body,


Some intresting YouTubes


Apex HF direction


Directional Recieving Antenna  HF KB7GF Mark Bauman

https://www.youtube.com/watch?feature=player_detailpage&v=i46kR0pynFw
https://www.youtube.com/watch?feature=player_detailpage&v=hBkzWQ9R91Q

Aha Moment



New Find Outs
https://www.youtube.com/watch?feature=player_detailpage&v=3LSJLlxbXiM
https://www.youtube.com/watch?feature=player_detailpage&v=DRlegDqOXU4
https://www.youtube.com/watch?feature=player_detailpage&v=8LXZt7DgbTA

On our Dutch Forum
Lee Hocool  Inteferometer
http://www.zendamateur.com/viewtopic.php?f=14&t=15649

[PA3BNX]

Hello Every Body,


New version of Mymapping on our sites

Also small maps of whole Neteherlands on the site now.

Take a look here

REDHAWK SDR

http://www.geontech.com/download/white_papers/AOC_Challenge_GEON.pdf

Take a look it's realy intresting !

Picture of running Arduino Doppler with lm3914 Peleorus and MyMapping 1.58 on the laptop

[PA3BNX]

Hello Every Body,

Today I wrote RightLeftRotating in Arduino.ino

With command R in ArduinoTerminal or button RL(in new MyMapping.exe) you can change the Doppler antenna rotation sequence from the antenna array

1234 1234 1234 1234 to
1234 3214 1234 3214

So one round right and then one round back to begin situation

What is the advantage of this?

The FM discriminator curve in the receiver can have a wrong
measurement if it's not symmetric.
This happens when the receiver is not exact adjusted to centre TX frequency or when the S-curve of the frequency discriminator is not
linear.

By rotating up and down you can average +/- frequency discriminator
errors.

If you switch between NormalRotation and RightLeftRotation
you hear the Doppler tone frequency halve.
The pelorus degrees stays the same


Of course CW/CCW adjustment stays the same.

Also with the plate antenna this is possible but it wil not give
benefit with AM detector



If you switch to RightLeftRotation you cannot use the arduino
on the sound-card with my soundDoppler.exe program.

So switch back to NormalRotation

Greetings,

PA3BNX

 

[PA3BNX]

Hello Every Body,

Nice to watch:

Narda

[PA3BNX]

Hello EveryBody,

I found this old RDF article about RDF RSSI meter hi
connected to a MW transistor radio.

Nostalgia !

And a PCB Layout for the SuperSimpleArduinoDoppler project.

in Sprint50 Not all ready I think..

You need wires to connect it to the ArduinoUno

But it can also wired to a Raspberry Pi GPIO Pins ?

Need to write software for that hi !!

[PA3BNX]

Hello Every Body,

Nice to watch this TDOA with Arduino

2015 Anatoly Kuzmenko.
 
https://youtu.be/eoOY659YMXo
http://coolarduino.blogspot.ca/

[I7SWX]

Hi Lodewijk,

I have started your direction finder project, basically similar to the 4013 & 4001. In place of the 4001 I have used a 4011, driving four transistors to drive the antennas diodes switching. This gives the same switching functionality.

Sorry if the following questions have been reported and answered in the discussion but I did a quick reading of some notes but I could not see anything.

I have some questions please:

1) Your 4001 solution defines, from top to the bottom, outputs antenna #4. #3. #2 and #1, mine has same selection. The solution with the 4017 gives the antenna selection, top to bottom, #1, #2, #3 and #4.
       a) which is the antenna # that is defined as North ?
       b) is the antennas rotation clockwise or anti clockwise, i.e North, East, South, West or opposite?

2) For the 4001 the clock synchronization is on the #4, while for the 4017 is on the #, right?

3) Which is the loss on VHF between the doppler switched array (using 4x dipoles) and a single fixed dipole connected to a receiver?

4) I have replaced the RFC at the dipoles with a 1:1 balun hoping this would help to reduce hands presence effect on the coax cale to the receiver, but I am not sure how much (if) changed. I will try to put on the dipoles short coax a clip-on ferrite element.

Thanks for your comments and congratulations for your interesting project.

Best 73

Gian
I7SWX

[PA3BNX]

Hello Every Body


Tnx's Josh Clough for this link

SDR RTL Dongle experiment wit three GP antenna.

An RTL-SDR Phase Correlative Direction Finder
http://www.rtl-sdr.com/an-rtl-sdr-phase-correlative-direction-finder/

Sources
https://github.com/tejeez/rtl_coherent

Youtube



I7SWX answers

In sounddoppler.exe software you can switch the sequence with CW/CCW 0/180
And correct with the actual bearing with the calibrate bar

Witch antenna is North is not very important you can calibrate 360 degrees

The loss compared dipole to monopole is theoretically 3 dB

With a 1 diode and rfc at a monopole antenna the
Coax shield earth at base of antenna ground plate (very important)
Or magnet feet with lots of capacity to car roof

The 2 diodes and rfc and leak R for dipole A rf 1:1 balun is possible after
the 2 diode and rfc.

Make sure if using dipoles the vertical dipoles have the top part of antenna connected to center conductor coax. (No phase shifts)

4 dipoles works best on stationary mast

On car roof always the 4 monopoles on ground plate.

For 70cm UHF on car roof you could have more monopoles
like 5 or 6 so the aperture is better and then the 4017 circuit is more handy.

On 2 meter VHF 4 antenna on car roof fits best.

If using indoor on a loft or something like that the monopole 4 array
with ground plate works best.

 

 

[I7SWX]

Hi Lodewijk,

thanks for the prompt reply.

I do appreciate your comments.

I have inserted the 1:1 balun as you did report, plus added a clip on ferrite on half dipoles coax cable from feed point to switching point. All antennay array box and support are plastic (external electric conduit and box).

I hope I can have the cable not interacting with the antennas having added the ferrite clipped  on.

I Also I have added a remote RF attenuator into the array, at lowest attenuation I loose 4dB.

I will use the DF on fixed portable installations, not mobile. The support is also PVC.

Yes, I have done the mark to be sure the center cox cable is connected to the top element of dipoles.

I have now a clear understanding of rotation and direction of antennas.

Thanks for the additional info for 70cm use. OK for the 4017 counter use. I found this info after I did assembled the 4011 solution, as I had that IC available.

Best 73

Gian
I7SWX

[PA3BNX]

Hello Every Body,

The arduino 1.04 software is ready now with

A potmeter connected to A1 +5V en earth for manual calibrating the lm3914 pelorus and the arduino doppler
without PC with USB.

If no potmeter connected or potmeter totally left or right turned it uses the
Terminal calibration(Mymapping.exe)

Center potmeter is 0 degrees calibration

The arduino with doppler hardware and led pelorus lm3911 draws about 80mA.

So it can easy run a time on a single 9 Volt block battery

[PA3BNX]

Hello EveryBody,

I programmed in the arduino doppler a 3 times flashing last Pelorus led after squelch closed.

Code: [Select]


void FlashPelorus(int d)
{
 //03-11-2015
 //ToDo let pelorus 3x flash with last bearing after squelch closed ?
 static boolean t;
 static byte c;
 static int de = cNodegrees;
 const byte m = 18 ;
 if (bAnalogPelorus==false){return;}
 
 if (d!=cNodegrees){de=d;} //Backup last degrees
   
 if (d==cNodegrees && de!=cNodegrees && c<m)
 {
  c+=1;
  if (c==2||c==5||c==8||c==11||c==14||c==17)//Flash frequency = c * cMainLoopDelay (250 mSec)
  {
   t=!t;
   if (t==true){AnalogPelorus(de);}else{AnalogPelorus(cNodegrees);}
   if (c>m){c=m;}
  }
 }
  else if (d!=cNodegrees && c==m)
 {
  t=false;
  c=0;
 }
}//Last bracket FlashPelorus



[PA3BNX]

Hello Every Body,

I bought this compass module

So now I am going to write the software

for a Fluxcompass working together with the SuperSimpleArduinoDoppler

GPS doesn't have compass if not moving.

Then this GPS fluxcompass module can be very handy.


hmc5883L module
pins Ucc,GND,SCL,SDA,DRDY


https://brainy-bits.com/tutorials/using-the-hmc5883l/

[jackdev23]

Hello,
I see the Arduino sketch and I would suggest to use https://www.arduino.cc/en/Reference/PortManipulation instead of DigitalWRITE.
Moreover, I think you can remove the 4x1N4148 (just set to INPUT by DDRC the pins of caps not used = 0)
For example (q_cyc from 0 to 3 selecting the cap of 4h7 in use on (pins A0...A3) and read on A4.

//sc_filter[5] = {B00000001,B00000010,B00000100,B00001000,B11110000};
           temp = DDRC & sc_filter[4];       // turn off the capacitor
           __asm__("nop\n\t");
           DDRC = temp;
         
          temp = PORTD & 0x07;               // next antenna
          PORTD = temp | activate_antenna[q_cyc];
           
          temp = DDRC & 0xf0;
          temp = temp | sc_filter[q_cyc];
           __asm__("nop\n\t");
          DDRC = temp ;       // turn on the capacitor;

          PORTC = PORTC & !sc_filter[q_cyc];

Hope is interesting for you
Ciao

[PA3BNX]

Hello Every Body,

Tnx's jackdev23 for the source code.

I hope I can understand it and use it...

Diodes are in now because the pins have no tri state  ?
I want 4u7 capicitors to float if not connected.


hmc5883L fluxcompas is fun !!!

[jackdev23]

You do not have tri-state but something similar  just using pins as input.