Monday, September 26, 2022

Solar K Index display from BOM using ESP32

There is significant solar activity at the moment. This activity changes radio propagation quite a bit for bad and good. One of the measures is called the K Index. I've been having good success with the little TTGO ESP32 + LCD boards and today created some code to fetch and display the K index.


This site has a good explanation which I reproduce here.

The K index is computed once every three hours (eight times a day) and the values can range from 0 to 9, with 0 being inactive, and 9 representing an extreme severe storm condition. The values are quadi-logarithmic.

K = 0 Inactive

K = 1 Very quiet

K = 2 Quiet

K = 3 Unsettled

K = 4 Active

K = 5 Minor storm

K = 6 Major storm

K = 7 Severe storm

K = 8 Very severe storm

K = 9 Extremely severe storm

Also, from here:

"The K-index, and by extension the Planetary K-index, are used to characterize the magnitude of geomagnetic storms. Kp is an excellent indicator of disturbances in the Earth's magnetic field and is used by SWPC to decide whether geomagnetic alerts and warnings need to be issued for users who are affected by these disturbances.

The principal users affected by geomagnetic storms are the electrical power grid, spacecraft operations, users of radio signals that reflect off of or pass through the ionosphere, and observers of the aurora."

To get the current value for Australia, in an easily machine readable form, I turned to our fantastic Space Weather Service of the Bureau of Meteorology. They have an API for this and other data documented here. Note that to use the API you must register with your email address and get an API key to use in requests.

There's not a lot to the code. It is built with the Arduino tool chain and uses the built-in esp32 http library and uses ArduinoJson to extract the figures. 

#include <WiFi.h>

#include <WiFiMulti.h>

#include <HTTPClient.h>

#include <ArduinoJson.h>

#include <ArduinoJson.hpp>

#include <TFT_eSPI.h>

#include <TFT_eWidget.h>

const char *kWifiNetwork = "SSID";

const char *kWifiPassword = "PASSWORD";

const char * API_KEY = "PUT YOUR API KEY HERE";

TFT_eSPI tft = TFT_eSPI();

WiFiMulti wifiMulti;

void setup() {

  Serial.begin(115200);

  while (!Serial) {

    ; // wait for serial port to connect. Needed for native USB port only

  }

  Serial.println("Starting...");

  wifiMulti.addAP(kWifiNetwork, kWifiPassword);

  tft.begin();

  tft.setRotation(3);

  tft.fillScreen(TFT_BLACK);

  tft.drawString("Starting", 10, 10, 4);

}

void loop() {  

// wait for WiFi connection

  if((wifiMulti.run() == WL_CONNECTED)) {

    tft.fillScreen(TFT_BLACK);

    tft.drawString("Connecting", 10, 10, 4);

      HTTPClient http;

      http.begin("https://sws-data.sws.bom.gov.au/api/v1/get-k-index"); //HTTP

      http.addHeader("Content-Type", "application/json");

      String payload = "{\"api_key\": \"" + String(API_KEY) + "\", \"options\": {\"location\": \"Australian region\"}}";

      Serial.println(payload);

      int httpCode = http.POST(payload);

      Serial.println(httpCode);

      // httpCode will be negative on error

      if(httpCode > 0) {

          // HTTP header has been send and Server response header has been handled

          // file found at server

          if(httpCode == HTTP_CODE_OK) {

              String payload = http.getString();

              // https://arduinojson.org

              DynamicJsonDocument doc(1024);

              DeserializationError error = deserializeJson(doc, payload);

              // Test if parsing succeeds.

              if (error) {

                Serial.print(F("deserializeJson() failed: "));

                Serial.println(error.f_str());

                return;

              }

              Serial.println("Deserialised OK");

              Serial.println(payload);              

              long k_index = doc["data"][0]["index"];

              const char*  analysis_time = doc["data"][0]["analysis_time"];

              Serial.printf("K Index = %ld\n", k_index);

              Serial.printf("analysis time = %s\n", analysis_time);

              Serial.println("Serial print OK");

              tft.fillScreen(TFT_BLACK);

              tft.drawString("K Index", 10, 10, 4);

              tft.drawString(String(k_index), 90, 30, 8);

              tft.drawString(analysis_time, 5, 120, 2);

            if (error) {

              Serial.printf("Json error");

            return;

            }


          } else {

            tft.fillScreen(TFT_BLACK);

            tft.drawString("Http error", 10, 10, 4);

            Serial.printf("[HTTP] GET... failed, error: %s\n", http.errorToString(httpCode).c_str());

          }

      http.end();

      }

  }

  delay(200000);

}

It varies during the day and I believe if K hits 5 things start getting serious.




All credit to the good folks at the BOM for making this easy and free to access.

Thursday, September 22, 2022

You can't beat a resonant dipole antenna

I'm a big fan of the Off Centre Fed Dipole. With a 4:1 balun and two lengths of wire you get multiple bands with good resonance. Recently I put up a dipole cut for 40m and could switch between the OCFD and the 40m dipole and it was clear that the dipole performed better.

The weather has been cold here but spring has arrived and I took down the OCFD and replaced it with a dipole cut for 80m. Resonance looks pretty good, if a bit narrow.


I used this dipole on the weekly Macedon Ranges Amateur Radio club net and other stations commented on how good, and improved, my signal was.

The antenna support tree has lots of space to hang baluns so I've now put up dipoles cut for 40m and 20m.


It's quite an effort tuning these antennas. Hoisting up, measuring, trimming, hoisting... but in the end I've got each of the antennas resonant in their bands. 

I use plastic egg insulators and fold the wire ends back and hold them in place with cable ties. This makes it easy to adjust the lengths as required for tuning.

The dead tree is a very handy support.


Getting lines over high branches can be a challenge. Dallas, VK3EB, was a great help with his big squid pole. I've also used a drone and most recently an arborist's throw weight.

Tonight I'm trying out 20m by running WSPR and performance seems excellent.


So far my antennas are all facing East-West and I think the next step is to have some dipoles facing North-South.

I was talking with Stephen, VK2BLQ, about all this and he said "you can't beat a resonant dipole".

Saturday, September 17, 2022

mcHF transceiver shown by David VK3DKR

David, VK3DKR, brought along the compact home built mcHF transceiver to the latest Macedon Ranges Amateur Radio club meeting today.


The radio is impressive and David reports excellent receiver performance and good reports of the transmissions when used on SOTA activations. Here's a brief snippet:


The amazingly good reception with just a clip lead antenna can be explained...

I used a HackRF to record a slab of the 40m band during the recent RD contest on my home antenna and then played back that recording into a whip antenna for David to receive.

Record:

hackrf_transfer -r capture  -f 7037000 -l 40

Play:

hackrf_transfer -t capture -f 7037000 -x 47 -R

On playback, the -x turns up the transmit power and the -R makes it loop when it reaches the end of the IQ recording. Note that the files get big quickly and my recording was over 3GB.

This is a terrific way to demonstrate a receiver when there isn't a good antenna available. 

Incidentally, my sincere thanks to David for thoughtfully bringing along a few J310 FETs which I mentioned on our club net I was waiting for. Very kind of you!

After 90 years who needs the ABC?

My view is that in this age of people getting their news from sites that optimise for engagement over facts, a source like the ABC is more vital than ever as part of a healthy democracy.

It was my pleasure to say a few words about the role of ABC Alumni at an event at Ballarat organised by ABC Friends Victoria.

We cut a beautiful cake, sang happy (90th) birthday and then heard from Matthew Ricketson the co-author if the excellent new book "Who needs the ABC?".

The ABC is under constant attack from the hard right, who think that the free market is the answer to everything and from some commercial media who think that the ABC prevents them from making larger profits.

Ricketson and Mullins' new book is a well researched defence of the ABC that knocks many of the oft-repeated arguments on the head with simple data and logic.

ABC Friends Victoria is a fantastic branch of ABC Friends. It is my pleasure to help them in any way I can.

Saturday, September 10, 2022

Dr Duino Explorer Arduino review

For prototyping new projects where an Arduino is to be connected with common peripherals, the Dr Duino Explorer board looks very useful. It's a good board with lots of useful components but the documentation is infuriating and there are attempts to up sell the purchaser at every step.


As you can see, there's LEDs, buttons, potentiometers, a light dependent resistor, a 128x64 OLED display, a bluetooth interface board, an ultrasonic range sensor (off board) and a row of eight NeoPixel RGB LEDs. Also there's a variable output power regulator.

In contrast to most other Arduino related products, visiting the DrDuino web site does not give you access to the construction or user manual. There is a link called Downloads but it tells you to go back and look in your spam folder for the instructions on how to log in to the site.


To get this basic information you must log in to the "exclusive" portal. Everything is strangely slow. Have you ever seen this on a modern web site?


I had to log in twice and it turns out that the site (Powered by KARTRA) is not compatible with the standard settings in modern browsers including Chrome and Safari. They suggest changing the default settings to re-enable third party cookies.

To be fair, the instructions are very detailed. What I found frustrating is that you have to step through them on the web site, one screen at a time. You are prevented from, for example, accessing the schematic until you've gone through every page up to that point.

In the end I visited each page and copied the content into a document which I could read on a tablet while constructing.

At several points during the construction DrDuino tries to sell you things such as PCB holder and side cutters with:

And... because you're a Dr.Duino customer, NO FULL PRICE FOR YOU!

There is a library to go with the board but I couldn't find it. It's not in the downloads area. Dr Duino happily uses libraries made by Adafruit but declines to share any work they've done with others. This seems counter to the norms of open source.

Anyhow, I don't want to be too negative. The board is good quality and has handy features on it. Construction went well for me and the OLED display and NeoPixel strip worked with the Adafruit libraries' examples unmodified.

Incidentally, I notice that despite all the security theatre, the link to the schematic seems to work even if you aren't logged in. Duh. 

Nuts and Volts has a good review that is quite informative - better in fact that Dr Duino's own documentation.

Guido, if you're listening, here are my suggestions to improve this product:

  • Make a single document manual that people can freely download. 
  • Put your "library" code up on GitHub (I'm pretty sure open source licenses you're using require this anyhow).
  • Sack Kartra unless they can get their authentication to work with default settings in Chrome and Safari.
  • Sack Kartra for stuffing up basic security on things like access to the schematic.
  • Don't assume users are running Microsoft Windows.
  • Tone down the "NO FULL PRICE FOR YOU" stuff.
  • The Arduino UNO clone supplied does not work out of the box on Ubuntu 22.04 by the way but there are solutions out there to fix this. (The serial chip collides with a brail device).

Friday, September 02, 2022

WTF Adobe - so many processes!

My wife had to install Adobe Acrobat on a shared Mac for her Uni work and I'm astonished at all of the processes this has added to the system. 

Adobe CEF Helper (GPU)

Adobe CEF Helper (Renderer)

AdobelPCBroker

AdobeCRDaemon

AdobeCRDaemon

AdobeCRDaemon

AdobeCRDaemon

Adobe Desktop Service

Adobe CEF Helper (Renderer)

Adobe CEF Helper

com.adobe.acc.installer.v2

Adobe Desktop Service Networking

CCXProcess

CCLibrary

Creative Cloud

Creative Cloud Helper

Creative Cloud Helper

Creative Cloud Helper Networking

Creative Cloud Networking

Creative Cloud Helper Networking

Core Sync

Core Sync Helper

My guess is that there's even more that I didn't recognise in Activity Monitor. The processes seem mostly idle but it's hard to understand why they are all required for something that just views and does some proprietary editing of PDF documents.

Most annoying is that in my account I now have a menubar button (no, it's not a menu) that if clicked asks me to log in to Creative Cloud. I hate you Adobe.


Thursday, September 01, 2022

ESP32 with 2.8 inch LCD display

I wrote recently about a little ESP32 board with a tiny LCD display from Lilygo that worked "out of the box" for me.

Another board from AliExpress, with a larger 2.8 inch display, gave me a lot of trouble before I got it going.

Described as "ESP32 Arduino LVGL WIFI&Bluetooth Development Board 2.8" 240*320 Smart Display Screen 2.8inch LCD TFT Module With Touch WROOM"

The board has an ILI9341 display board bonded to the PCB and connected via an SPI interface.

After trying all sorts of combinations of pins for the SPI interface, and having the screen remain dark, I shone a torch obliquely at the screen and found that it was working fine but without the backlight was not visible.

Switching to MicroPython makes experimenting a bit easier. I used this ili9341 python library and with the generous help of the author rdagger, figured out that the backlight is connected to GPIO pin 21.

Here's how I set it up for drawing:

from ili9341 import Display

from machine import Pin, SPI

Pin(21, Pin.OUT).on()

spi = SPI(1, baudrate=40000000, sck=Pin(14), mosi=Pin(13))

display = Display(spi, dc=Pin(2), cs=Pin(15), rst=Pin(12))

display.draw_text8x8(0, 0, 'Built-in', color565(255, 0, 255))

As mentioned in other posts, I'm currently using these things to monitor solar power generation so I can time the use of high energy appliances with the sun hitting the panels here. A device like this, that can use internet services has all sorts of applications and a larger screen could be handy.

Monday, August 29, 2022

Creality Ender 3 v2 3D printer with just enough Blender

My sister Jane once asked for a horse because "everyone in her class has a horse". 

Sometimes it feels that way with 3D printers. Several people have recommended the Creality Ender-3 printer as a good starter model. I ordered the Ender-3 v2 and paid AU$360. (Excellent value).

What arrived was a well packed kit. The base is already put together but you need to do the rest.


They do supply everything including tools such as hex keys, screwdriver, spanners and even side-cutters (which are used to cut filament). I was a bit daunted by the process but took my time and it came together.

STL files can be loaded from a micro-SD card. They supply a card but my printer wouldn't read it for some reason. I formatted another card FAT32 and that worked fine. I was unsure that I'd got the base level enough but my first print, the Chinese cat you see below came out impressively well:

As you can see from my early prints here, my first use for a 3D printer is to make tuning knobs for radios. (Oh, and toys for the grandson).

There are many pre-made models ready to slice and print at Thingaverse, Thangs, Printables and others but I want to be able to design my own.

I scanned my face with the iOS app "3d Scanner App", exported to STL, imported in to Blender to tidy up and printed it:

Blender

Blender is open source software that works well on Linux, macOS, and yes, even Windows I hear.

It is amazing and capable of high quality 3D rendering and animation. Much more than I need.

Just enough Blender skills took a few days but now I can add objects, size them and punch holes in them with other objects. The trick here is to use a boolean between the main shape and the shape that will be the hole.


There are many videos on how to do things in Blender but I found the official tutorial from the BlenderFoundation YouTube channel was excellent.

The trick to making holes in objects is shown in this video on booleans.

Blender can export to STL or OBJ. I use the Creality slicer to produce gcode for the printer.

So far, my only failed print was a Millennium Falcon model that had a large overhang and ended up as a pile of hair. I have a great deal to learn but it is amazing technology.

Lilygo TTGO ESP32 board draws a graph of power from Enphase solar

Little "Arduino" projects around here often require a display and connection to the internet. ESP32 based boards are an obvious choice but which one? There are lots about but often the documentation is difficult to use and may be only available in Chinese.

I've found a board that has the features I need and has excellent documentation. Mine come from AliExpress stores and sell for about $15.

My latest project draws a nice graph of our solar generation and power consumption.


No credit is due to me, I'm just using the excellent work of others. My code is here.

Briefly, it pulls JSON data from the web server in the Enphase solar controller and keeps two arrays of past values which it plots.

The Arduino IDE version 2 is getting really good and I notice it now has a debugger but it only works with a few ARM based boards. I have ordered an Arduino Zero to try it out.

I had some errors in my maths (which is pretty terrible) and it takes a long time to debug if you have to print to serial, build and download, run to see what it says. The debugger allows setting breakpoints and inspecting variables.

One thing I find odd about the Arduino IDE is that it builds every time, even if I haven't edited a file. If I build to check syntax and then click Run it builds again. Surely they are using make or CMake which would compare the built binary's modification date with the source code and only compile the files that have changed?

Monday, August 15, 2022

Experimental remote operation of an IC-705

I founds some wonderful macOS SwiftUI code by Mark Erbaugh that implements the Icom remote access code. He's got the basics going and I've enhanced it just a bit with tuning controls and mode buttons. Today I managed to port it to iOS. Here's a video showing the basics.


My enhancements to the macOS version are here.

Mark's version is here.

He builds on top of Kappanhang here and WFView here.

Open source software is a wonderful thing.


Thursday, July 28, 2022

New open source SDR available from HFSignals - sBitx

I've been following the progress of an open source SDR transceiver, the T41-EP, from Albert Peter and Jack Purdum for some time. It's a great contribution but the author's understanding of how open source normally works is a little unusual.

By contrast, Ashhar Farhan, VU2ESE, of HFSignals, exemplifies best practice. 

HFSignals new SDR transceiver, the sBitx, is available to early adopters. The radio has a large graphical touch screen that shows a waterfall. Inside there is a standard Raspberry Pi which is set up as the software development environment - great idea!

Here's my video of unboxing the sBitx, tuning around and having a not great first contact.


Later, on a different (more resonant) antenna, I did not have RF feedback trouble. It might be that the SWR is quite critical. The operation manual says "At times, with high enough gain and high SWR, RF can get into the mic and cause self-oscillations. Monitor the modulation on the display if you are setting the mic above 50 to be sure that it doesn’t happen."

"The sBitx is a 40 watts, fully open source, high performance HF SDR transceiver with in-built popular modes like the FT8, RTTY, PSK31, etc."

Design paper.

The source code and circuit diagrams are here on GitHub.

Operating manual.

Assembly manual.





There is discussion about the sBitx in the Bitx20 group (which should probably be re-named).

Having a computer inside that can be internet connected opens up all sorts of interesting possibilities for this platform.

Update

Since the original unboxing video, where audio stopped, I have updated the software to 1.1 and that problem hasn't re-occurred.

On the RF feedback... I was using my off centre fed dipole. Reading the ARRL Handbook I saw that command mode suppression on the feed line is "essential". This has now been added. I guess my normal (commercial) radio is more forgiving.

Tuesday, July 26, 2022

QDX with Fldigi on Ubuntu 22.04

The QDX works brilliantly with WSJT-X but I have struggled to get it working with Fldigi on Linux.

I'm pleased to report that I just had an Olivia 8/250 contact over a distance of 732km with VK2BLQ using Fldigi on Ubuntu 22.04.

Thanks to KJ7LVZ for the tip to install Pulse Audio Volume Control (from the Ubuntu App Store). That let me adjust and monitor send and receive audio levels.

In Fldigi I set the audio devices both to "pulse".

In the QDX settings I set the audio cycles to 1 (down from 480) as suggested by G3SPL. The larger number of samples is fine for slow changing modes like WSPR or FT8 but not good for fast modes like Olivia. Also I increased the receive gain to 75, up from 60 (I think), so I could see something on the waterfall in Fldigi.


Here's the Pulse Audio Volume Control window:


While I'm here, I've been using `screen /dev/ttyACM0` to configure the QDX but it's difficult to send ^Q as that's used for XON/XOFF. The trick is to type ^AQ. Hans, it might be good if there was another key to exit a menu than ^Q as I think many serial terminals might use ^Q for flow control.

Thursday, July 21, 2022

Updated QDX Firmware to 1.04 - working very well on WSPR

The QDX is a tiny FSK mode transceiver from QRP Labs which works amazingly well. This week, new firmware was released which improves transmit a little. I've been running it on 40m here and results are very good.

My friend Stephen, VK2BLQ, is 800km away in Sydney and he received my 3W at +18dB last evening.

I have a theory that direct generation of RF for digital modes in rigs like the QDX produces a cleaner signal than you get by mixing audio up to RF in a sideband radio and so decodes are better.

At a similar time I had a transmit cycle that was spotted by 45 stations around the world.


 Changes in 1.04:

  • Resolution to the Rev3 PCB "popping" issue (RF discontinuities during TX).
  • Audio streamed to the PC during Transmit is now set to zero (silence).
  • 50 millisecond transmit timeout on cessation of audio from PC (protects QDX e.g. if PC crashes).
  • No CAT command TX timeout (configurable enable and timeout duration).
  • Removed unnecessary 48ksps clock domain sync PC vs QDX.
  • Enables PTT output connector, with grounded and +5V outputs individually controllable by band.
  • 12kHz IF offset is removed when you enable IQ Mode.
  • Transmit is disabled when you are in IQ mode. 
  • Gain is now in dB.
  • Gain is now configurable per band.
  • New "Band Configuration" screen where you can configure the list of supported bands.

The firmware upgrade process couldn't be easier. You interrupt the power up cycle and then re-plug the device. It mounts as a disk drive and you drag over the firmware.

After running for a few days on 40m I see I'm #3 on the WSPR Challenge for receiving. 


Hard to beat Phil, VK7JJ though!

Thursday, July 07, 2022

Live PV solar monitor

If you have solar photo voltaic panels it's good to know how much is being generated so you can choose when to use power such as the tumble dryer. Using power locally, from the panels, is much more economical than receiving the feed-in tariff and buying power back at other times.

In a previous home we installed a PV solar system that had a Fronius inverter. I was impressed with the low RF noise emitted by this product and pleased to find that it had a JSON producing web service endpoint that I could poll to see how much power was being generated.

At our new home there is a system with micro-inverters and an Envoy controller. The micro-inverters do produce noticeable RF noise but bear in mind that this is a very low noise location so I might be a little sensitive to it.

It turns out that this system also has JSON producing web services. The system, once I figured out how to connect to our Wifi, has a web interface at http://envoy.local 

By enabling Developer mode in the browser I was able to see that the web page calls back to endpoints including:

  • home.json
  • production.json
  • Inventory.json
  • info.xml
  • dba.json
I haven't explored them all, but production.json gives me the data I need.

Here's a snippet showing how I get the generated power and the used power from the content returned from production.json

DynamicJsonDocument doc(3072);
DeserializationError error = deserializeJson(doc, payload);

if (error) {
USE_SERIAL.printf("Json error");
return;

}

// Extract current power generated from the Envoy controller JSON

long genWattsNow = doc["production"][1]["wNow"];
long useWattsNow = doc["consumption"][0]["wNow"];

Using a nifty M5StickC device, which has an ESP32 and a little LCD display, I've stuck together sample code for an http client and Json parser to display the currently generated power and the currently used power. I'm happy to share the code but honestly, there's not much to it beyond the HTTP sample code.

Thursday, June 30, 2022

DMR in Australia - what I've learned

DMR digital radio is intriguing but confusing. I live at a location where I can't reach any DMR repeaters so I'm using a pi-star hotspot to access global talk groups.

The hot spot provides a local radio link to my TYT MD380 handheld and connects to the DMR network. There are several networks available in Australia:

  • VKDMR - the official network that includes most repeaters
  • FreeDMR - an alternative network apparently objecting to the control by repeater operators
  • Brandmeister - this seems more global than the others
  • VKMultnet - VK2 based connects to VKDMR, Brandmeister, C4FM and P25
After trying the first three, I've settled on Brandmeister. I like the way talk groups are configured through a web interface on the site rather than a rather cryptic "options" string in pi-star. You do need to register and set a password but this was all pretty easy.

Brandmeister including many active track groups such as 91 which has traffic pretty much 24/7.

The radio's programming is done by editing its "code plug". There's no real code, it's just configuration settings. Initially, I downloaded a code plug which had every repeater in Australia in it but I found the number of settings in there overwhelming and so I started from scratch with a minimum setup for my needs through a hotspot.

DMR is designed for commercial use and many of the features are not used for ham radio and many of the terms are alien. 

On the MD380 you choose a "zone" which is typically a set of channels for a repeater or a hot spot.

Here's my process to add a talk group or contact to a zone for my radio.

I'm using the excellent editcp (edit code plug) on Linux.

First I add a group or personal Contact.


Next I add an "RX group". I'm not sure if this is necessary.


Now I create a Channel that combines the contact and RX group.


Finally I create a zone and add the Channels to it.


Then upload the code plug to the radio.

The Zone, in my case "HomeSp" is chosen via the menu and then the knob on top selects between talk group or contacts.

I'm using the third party MD380 Utils firmware so I have some extra features such as showing more information about who's talking and promiscuous mode where I hear everyone even if not on that talk group.

Private calls

Adding another station's DMR ID as a contact and (via the steps above) adding it to a zone gives me the ability to call that station privately. I think this only works if we're both on the same DMR network. Ross EX0AA and I have been able to speak using this mechanism with good success.

Activity

You can get s sense of the activity on Brandmeister via the LastHeard page. You can listen in via the Brandmeister Hoseline. (Click on a box with a red outline).

Finally

I am really just starting to figure this stuff out. Please comment with corrections or clarifications - I'm sure to be mis-understanding this rather confusing world.

Thursday, June 23, 2022

Guest on ABC RN's Download This Show

Facebook pointed out that I've been appearing on Marc Fennell's Download This Show for over ten years. Since COVID and my move to country Victoria, I'm a remote guest but you probably wouldn't know as a listener.

This week:

"After 27 years Microsoft has retired Internet Explorer, a product which transformed the way people engaged with the web. A timely end, or gone to soon?

Plus, new data reveals that Australian border force searched more than 40,000 mobile devices in five years. Can they all be justified?

And, Instagram introduces parental controls to a curb mental health crisis."

The show airs a few times on ABC Radio National or you can listen here.

Tuesday, June 07, 2022

Built the QDX from QRP Labs

The QDX v3 kit arrived yesterday and today I've finished the build.


This transceiver is tiny, about the size of a playing card deck. It does FSK modes on four bands: 80, 40, 30 & 20m. Five watt output and a great receiver from what I can see so far.

The QDX connects to a computer with a single USB cable that comes up as a sound card and does TS-440 compatible CAT control - so very convenient for possible field use.

It can be built for 9 or 12V operation - I went with 12V as I have it more available.



The assembly manual is the best I've ever followed. Clarity and detail with lots of handy tips from Hans. The board comes with all the surface mount components already soldered in place so the main job for the constructor is a few diodes, capacitors, transistors and winding the toroids. 

Page 34-76 of the assembly manual describes the design and could be a book on its own rivalling the recent Software Defined Radio Transceiver Book by Peter & Purdum.

I took my time and had a break after a few toroids. One of the joints didn't connect but following Hans' advice to check continuity found this problem at the time. On initial power up I blew a 25A fuse - which was a bit alarming - but I think it was my DC connector shorting. All was fine with another connector.

Running with wsjt-x on Ubuntu Linux 22.04 got immediate spots on each of the bands (shown here in WSPR Watch).



There is diagnostic software built-in that can be operated via a serial (over USB) terminal. Here is the low pass filter band sweeps on my unit. I'm interested to know if this looks normal or should I perhaps remove a turn from the 80m low pass filter for example?





Here's my portable operations configuration. The QDX is the smallest part:



I can't recommend this kit too highly.

Tuesday, May 31, 2022

Slow scan TV activity on 40m

Stephen, VK2BLQ, alterted me to SSTV activity on 7.171Mhz. I ran qsstv on Linux and easily had some contacts. Leaving it running means that it gathers images decoded for later view.

Hooked up to the IC-7300 via USB audio worked fine but I'm having trouble with CAT control of transmit - the app runs incredibly slowly for some reason. I had a voice contact with VK3HK who mentioned that he had the same issue.

QSSTV has many modes, the first one in the list is Martin 1 so I used that. Happily the receive software figures out which mode is being used automatically.



Stephen, VK2BLQ keeping warm.