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Lime SDR / Testing the Lime mini SDR
« Last post by Anton Janovsky (ZR6AIC) on December 20, 2018, 09:33:08 am »
Here is the details on how to test the Lime mini SDR

This repository will have all my Lime mini configurations.
Installing soapysdr on ubuntu 18.10

sudo apt-get install python3-pip python3-pyqt5 python3-numpy python3-scipy soapysdr python3-soapysdr #packages for soapysdr available at myriadrf PPA
cd /usr/share/doc/soapysdr-tools/ sudo add-apt-repository -y ppa:myriadrf/drivers
sudo apt-get update
sudo apt-get install limesuite liblimesuite-dev limesuite-udev limesuite-images
sudo apt-get install soapysdr-tools soapysdr-module-lms7
sudo apt-get install soapysdr
LimeUtil --info
SoapySDRUtil --info
SoapySDRUtil --find="driver=lime"
Testing the Lime Mini

LimeUtil --info
LimeUtil --find
SoapySDRUtil --info
SoapySDRUtil --find="driver=lime"

cd /home/anton/lime-tools/build
sudo ./LimeMon
sudo ./LimeScan


LimeQuickTest --no-gui
LimeQuickTest --gui
#testing lime

Testing the transmitter in Gnuradio.

Link to block source
Here is a Gnuradio block that will modulate the Lime mini sdr with Fm from Microphone and 1 Khz zone.
In the gnuradio radio directory is a working Transmitter testing code.

Here is the settings for the Lime mini. (you need to install the soapySDR drivers.

Screenshot of Application
Changing the PTT value to 1 enables modelation.
Changing the enable tone to value 1 will switch the modelation from internal Microphone of laptop to the 1Khz tone generator.
The Modulation can be seen in the FFT Plot box.
How to control your Generator using the transfer switch.
I wanted a way for my Generator to switch over from city power to my generator and when the city power come back up it must automatically switch the Generator off and switch back to city power.
The auto transfer switch had a monitor output that was used to detect when the city power supply is up or down
This monitoring output was used to control the Generator.
This Transfer switch is available from Giga Technology

My requirement was as follow.

    When my city power is down I will start the Petrol Generator manuely for now.
    Then the Automatic transfer switch will switch over to my generator.
    I the switch over the toggel switch on the surcuite in block diagram and switch of the generator on/off switch.
    The relay will now hold the on/off switch connection in the on position until the city power comes back up and the automatic transfer switch switch back to city power
    Because  the transfer switch switched back to city power the power to the Relay is now disconnected and the Generator stops.
    This system gives me at least a auto stop and transfer back to city power capability
    My next step is to build an auto start and chock configuration for the Generator when City Power goes down.
    This block diagram explain how I did this. Block Diagram of Automatic Power Transfer switch.

Link to github
How to Connect the SIP800L Wireless GSM GPRS Module Arduino.
This Unit is available from Giga Technology
Data sheet pdf 
Programming manual pdf

Connection Diagram

If you want to Create a GPS tracker and send your position via GSM (Ideal for Balloon tracking)

Code examples.

/*             GSM MODULE TEST
  *when you type in 's' the program will invoke
  *function to SEND AN SMS FROM GSM module.if the
  *user input is 'c ', the programwill invoke the
  *function to

#include <SoftwareSerial.h> //including software serial library

SoftwareSerial sim800l(2, 3); // create a constructor of SoftwareSerial

void setup()
  sim800l.begin(9600);   // Setting the baud rate of GSM Module 
  Serial.begin(9600);    // Setting the baud rate of Serial Monitor (Arduino)

void loop()
  if (Serial.available()>0) // checks for any data  coming through serial port of arduino.
   switch(   //
    case 's':
    case 'c':

 if (sim800l.available()>0)
   Serial.write(; // prints the data collected from software serial port to serial monitor of arduino

void SendTextMessage()
  Serial.println("Sending Text...");
  sim800l.print("AT+CMGF=1\r"); // Set the shield to SMS mode
  sim800l.print("AT+CMGS=\"+2783*******\"\r");  // change to your number
  sim800l.print("This is a Test text message from SIM800L "); //the content of the message
  sim800l.print((char)26);//the ASCII code of the ctrl+z is 26 (required according to the datasheet)
  Serial.println("Text Sent.");

void DialVoiceCall()
  sim800l.println("ATD+2783*******;");//dial the number, must include country code

#Hope this help

More command details here.
Data sheet pdf 
Programming manual pdf

The Radio Digi Board will allow you to connect Conventional Audio out and Audio inputs from a computer sound card to a Amateur Radio Transceiver to allow the computer to receive digital modes and transmit digital modes via your Amateur Radio.
What type of Digital modes is possible.Basically anything that is available via software on your Laptop or Computer.
RTTY, FSK, PSK, CW, APRS, ......

The Radio Digi Board will allow you to connect Conventional Audio out and Audio inputs from a computer sound card to a Amateur Radio Transceiver to allow the computer to receive digital modes and transmit digital modes via your Amateur Radio.
What type of Digital modes is possible?

Basically anything that is available via software on your Laptop or Computer.
RTTY, FSK, PSK, CW, APRS, ......

How dose the Radio Digi Board work?

    For the Transmission part the audio from Audio from Laptop or PC is isolated via a 1:1 audio transformer with an additional output potentiometer to adjust the output audio for the radio Microphone input.
    For the receving part of the Audio from the External speaker of radio is isolated via 1:1 audio transformer with an additional potentiometer to adjust the level for your computer / Laptop Line in or microphone in connector.
    The PTT of the Radio can also be isolated from the Laptop USB to RS232 adapter via the on board opto idolator witch will pull the Radio PTT connection to ground with an open collector transistor.
    By making the RTS pin high on the RS232 adapter will allow the Opto led to light up and switch on the open collector transistor.
    Most of the Digital Modes applications have the RTS pin configuration to pull PTT on as the standard Configuration.

The board isolates the radio from the computer to eliminate ground loops witch is normally the main reason for audio noise and also protects your radio from implicit ground.

You could simply enable VOX on radio witch should put your Transceiver in TX mode as an simple configuration. The radio has voise/audio detection to put it in Transmitting mode.

Vox sometimes need some time delay for the radio to get into TX mode before you send the Audio for your Digital mode and most Digital mode software support this delay.

Most of the new modern radios you could disable de-emphasis on the RX audio witch is needed for most digital modes if your radio dont have digital mode settings. (Audio response must be linear over the total Audio frequency band)

Additional RC circuit could be added for Older radios that can't disable deemphasis. The same applies to Microphone frequency flatness

If you have the older transceivers with no VOX capability that is not a problem by just adding the USB to RS232 cable and connecting it to the Radio Digi Board to isolate the PTT ground frm laptop and radio.

Most radios has pull to ground to enable th PTT.

Here is the Diagram of the Radio Digi.

Connection Diagram.

Here is a connection diagram for most Amateur Radios

Here is the connection Diagram for the yaesu FT857
Balloon Project.

Just wanted to give some feedback regarding the DRA818 module I bought from you. We used it in our high altitude balloon this past saturday hooked up to raspberry pi zero to make a rudimentary sstv came. It worked great! We even got confirmation of perfectly received images in Bloemfontein and Secunda. Unfortunately the actual camera came loose in the payload so most of the images were useless (inside of the payload). But the concept worked great! I used the pi pwm output to generate the sound (through a filter) that was connected to the mic of the dra818 module. PTT was switched with a transistor also from the pi. On the pi I have a bash script that got executed every 5 minutes. It took a picture. Added overlay text, converted to a sound clip with the sstv encoding and then played over the pwm pins. The dra818 module was used at low power setting (think about 400mW?). Also used a diy dipole antenna on the payload (not pictured)

Final prototype:

Next step is to make it smaller and more power efficient, but very happy with the results :)

Anyways, figured you might like some feedback.

Thanks for the shop, have more purchases lined up for payday.

How to Create a Linear Transponder using a RTL Dongle and HackRF with Gnu Radio.
I wanted to test the concept of a linear Transponder and how difficult would it be to build it with conventional components.

Link to Blog with full details here
Hardware Configuration
Hardware required to build the Transponder.

    SDR IQ demodulator with rtl dongle (RF In)
    SDR IQ DSP processing system. Gnu Radio (DSP processing)
    SDR IQ Modulator. HackRF (RF Out)
    Background management system. (OBC) for additional telemetry.

Software required for Transponder.

    SDR IQ demodulator. rtl dongle (RF In)
    SDR IQ DSP processing system. Gnu Radio (DSP processing)
    SDR IQ Modulator. HackRF (RF Out)
    Background management system. (OBC)

Video of working Transponder.

Gnu Radio.

Transponder Block Diagram
RTL SDR Block.
RTL-SDR Source
Low Pass Filter Block.
Low Pass Filter Block

AGC Block.
AGC Block
Power Squelch.
Power Squelch
Osmocom Sink. (HackRF)
Osmocom Sink (HackRF)
FFT. (Spectrum View of input)
FFT Spectrum View
REF: Power point Slides at AMSAT SA
Ref:Source code is available on Github Version 4
Link to Blog with full details here
This projects code is available from Github
This code is working but has lots of place for improvements .(project started 14 Sep 2017) This project will have the files for a Cube Sat Telemetry system Using Raspberry Pi Transmitter Board.

I will be using a External GPS and temperature geometry meter to generate the Telemetry Data. The System will use GPDS and direwolf with Beacon configuration to send System data. The Diarewolf RX will be a RTL dongle withe a sharp Saw or Crystal filter as a front-end. The transmitter and receiver can be configured to be FM repeater as well. Here is a Block diagram of the BACAR Balloon telemetry system.
Link to RF Hat for raspberry pi Alt text
Image of RF transmitter hat 2M band (any frequency from 1 to 500MHZ can be assembled for a band.

Balloon Satellite picture.

More Pictures.

More Pictures

More Pictures
Here is information how to get your Echolink link or Echolink repeater up and running using a Rapberry Pi and Baofeng HT.
Use only low power on Baofeng uv-5r as it could overheat when TX is on two long.

Or you can connect it to Linux Laptop

What hardware do you need.
1) "EASY DIGI" Baufeng UV-5R INTERFACE for laptops, desktops and Raspberry with usb audio. (Easy Digi) Asembled)
2) USB 2.0 To 3d Audio Sound Card Adapter Virtual 5.1 CH.
3)The Raspberry Pi 3 Model B
5) Baofeng power eliminator

Software instelation of svxlink
Download from here
I will add the details how to install and configure the svxlink
Programming ESP8266 ESP-12E NodeMCU Using Arduino IDE

Link to programing details
Configuring my wifi dongle on the Raspberry Pi to connect to my network router.

Configuring my wifi dongle on the Raspberry Pi to connect to my network router.

Generic Wifi dongle used on my Raspberry Pi

I had to get my router details and had to configure the following configuration files.
I wanted to give my Raspberry Pi a spear static IP so I always know what it is on my network.

I edited the following files.


I added the following at the end. I was using WEB encryption and shared key on my router.
Change the details in yellow for your router if you use web encryption with shared key.
use your favorite editor
sudo vi /etc/wpa_supplicant/wpa_supplicant.conf

#Configeration of the file /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
        ssid="MyRouter"  # your router ID
        wep_key0="0123456789123"  # or 13 characters, or a hexkey starting with 0x your key

Save and exit
And the change the following file

Edit the file as follows in the section configuring wlan0
I gave my Raspberry pi a spear static Ip on my network so always now what the ip is and don't use DHCP so I will not know what the Ip will be
use your favorite editor

sudo vi /etc/network/interfaces
auto wlan0
allow-hotplug wlan0
#iface wlan0 inet dhcp
iface wlan0 inet static
address  #Static Ip
netmask # Ip mask of network
gateway # IP gateway of router
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp


And reboot Raspberry Pi  sudo shutdown -r 0

ping your new Ip on Wifi network


And it should now work.
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