Sunday, 17 June 2018

Built TAURUS 40m SSB Exciter

As an advanced part of the BARSicle project the plan is to build RV3YF's TAURUS SSB Exciter and 5W PA.

I have received the kit for both, and so far built to SSB Exciter,

SSB EXciter

I have made a couple of modifications which I hope will work, these are to include input BPF for the VFO input of 4.0592 - 3.9592MHz (tuning 7.0 - 7.2MHz) and for the SSB filter input at LSB = 11.062MHz, USB = 11.056MHz. These signals will be provided by the VFO synthesiser using an Si5351, the third Si5351 output will be on 7.0-7.2MHz for our Direct Conversion RX.

Tuesday, 12 June 2018

BARSICLE 2. Arduino Nano

2 Arduino S 001 2 Arduino S 002 2 Arduino S 003 2 Arduino S 004 2 Arduino S 005 2 Arduino S 006 2 Arduino S 0072 Arduino S 008

CODE

// BLINK

void setup() {
  pinMode(13, OUTPUT);        // set pin 13 as an output
}

void loop() {
  digitalWrite(13, LOW);      // pin 13 LOW
  delay(1000);                // wait 1 sec
  digitalWrite(13, HIGH);     // set pin 13 HIGH
  delay(1000);                // wait 1 sec
}


// BLINK 1

#define LED 13

void setup() {
  pinMode(LED, OUTPUT);        // set pin LED as an output
}

void loop() {
  flash(100);                  // timings
  flash(100);

  flash(1000);
}

void flash(int t) {
  digitalWrite(LED, LOW);     // pin LED LOW
  delay(t);                   // wait t (ms)
  digitalWrite(LED, HIGH);    // set pin LED HIGH
  delay(t);                   // wait t (ms)
}


// VOLTS
// measure +5V output, mine was 4.62

float volts;                                          // ADC voltage read

void setup() {
  Serial.begin(9600);                                 // start serial comms
}

void loop() {
  volts = analogRead(A0) * 4.62 / 1023;               // read ADC -> volts, "+5V" ref
  Serial.println(volts);                              // display on Monitor
  delay(100);
}

BARSICLE 1. Arduino Sketches

1 Arduino S 001 1 Arduino S 002 1 Arduino S 003 1 Arduino S 004 1 Arduino S 005 1 Arduino S 006 1 Arduino S 007 1 Arduino S 008 1 Arduino S 009 1 Arduino S 010

BARSICLE INTRO

Here's the slides I presented to introduce BARSicle

BARSicle intro 001 BARSicle intro 002 BARSicle intro 003 BARSicle intro 004 BARSicle intro 005 BARSicle intro 006

BARSICLE BASICS

This is an outline of the BARSicle project, to build a complete homebrew 40m SSB station. The aim is to build technical know how among club members, from beginenr to advanced levels - LEARN, CODE, BUILD.

It includes a course in coding for the Arduino microcontrollers

BARSICLE BASICS 001 BARSICLE BASICS 002 BARSICLE BASICS 003 BARSICLE BASICS 004

Input filter for SA612 mixer

We are planning to build a simple Direct Conversion RX, but with a Si5351 digital sythesiser VFO. The Si5351 has a square wave output with lots of harmonics. In order to limit these and avoid unwanted mixer products a simple filter is to be put infront of the VFO input.

IMG 0233
This is simply a 22pF capacitor and a 22uH inductor (commercial resistor-style) loaded by a 51R resistor. The Si5351 happily drives a 51R load with about the right input level for the SA612. The response of this arrangement is,

Screen Shot 2018 06 12 at 12 50 35

Which looks good. Now to try it in practice...

Saturday, 9 June 2018

How's your propagation?

So why go digital? Because digital sends data. And that data can be used for other purposes than simply having a QSO. For example the new FT8 mode both allows you to conduct a digital QSO in a minute or so, and build up a pattern of your propagation, but also using additional software gives you an insight into who you are receiving and where they are on the map.

What do you need?

First an SSB receiver (or transceiver), next an interface to get the audio in/out to your PC sound card. All pretty straight forwards and can be implemented with a cheap USB audio interface dongle. Then you need the software...

Software

WSJT-X first. You tune your RX to, for example 7074kHz for 40m, USB. The incoming signals of the new mode FT8 will display on a water fall (audio from 200-2000kHz adjustable). And every 15 seconds as others transmit you will receive their call signs, signal strengths and location.

Screen Shot 2018 06 12 at 08 41 08

See how the software is able to decode even the weakest signals (about 20db below the noise!)

WSJT sends out information packets by UDP to a local web address 127.0.0.1: 2337. This can be picked up by other software running on your computer.

GridTracker software picks up the WSJT packets, and plots the received station on a map.

Screen Shot 2018 06 12 at 08 43 53

That's a pretty good way of seeing the current propagation conditions.