Saturday, November 30, 2019

ABC celebrates 80 years of international broadcasting

80 years of international broadcasting by the ABC was celebrated this week at the headquarters in Ultimo, Sydney.

David Hua, ABC Head, International Strategy introduced the event.

Geraldine Doogue was the MC for the evening. She described the International division as “Taking Australian culture beyond its shores”. Doogue described ABC International as the very best of the ABC and said that the people who work in it have a sense of pride in Australia and work out how to present it to the world.

Ita Buttrose, ABC chair, said “The birth of Australia’s international broadcasting service came at a time of global upheaval, uncertainty and disruption. Australia seemed far removed from the epicentre of conflict in Europe, but the technology of cable and wireless brought the war in to living rooms across the country.”

As Ms Buttrose noted in her recent speech at the Lowy Institute, radio technology also gave Australia the opportunity to speak directly, for the first time, to its near neighbours, countering the propaganda and fake news of the day.

Buttrose referred to the book “This is the ABC”, a history by Ken Inglis, where the author noted that following World War II, when it looked like the ABC’s international service would be drastically cut, the government was warned that if Australia gave up its international frequencies, someone else, perhaps the Russians, would move right in. That was enough to change the Government’s mind and in the post war period, Radio Australia flourished as an integral part of the ABC and served as a vital and effective diplomatic tool.

“Just like the early days of international broadcasting, a disruptive world order, rapid technological change, the growing influence of super powers in our region, and the use of media as a geopolitical tool; are all still very familiar to us today.”

The ABC International service of today is quite different to its past. (Hint: much smaller, and lacking shortwave -editor). Some changes are a natural evolution due to technology and audience demographics, but the current form has primarily been brought about by necessity.

However, Ms Buttrose is optimistic about the future. “In recent weeks, both Prime Minister Morrison, and the Minister for the Pacific and international development, Alex Hawke, have spoken of the importance of marshalling resources to engage with and influence the region and the wider international community”.

“The Minister for Foreign Affairs, Marise Payne, has encouraged Australian communities and institutions to take Australian values to the world in the interests of promoting peaceful, open and inclusive international relations”.

Ita Buttrose went on to say “I believe the ABC has a fundamental role to play in achieving these objectives. We are Australia’s trusted voice in Asia and the Pacific. We have a proud record of achievement, telling Australian stories, reporting fairly and fearlessly, presenting Australian culture and education, and delivering valuable information in times of crisis, and we’ve done this for eighty years”.

“Crucially, our point of difference from state broadcasters and other international media is that the ABC has an independence from Government and the longevity to secure a foundation of mutual trust and respect. An unmatched expertise and understanding. We talk with, not to, our neighbours”.

Buttrose argued that if Australia is to step up in the region, the ABC is an existing platform from which to step up.

David Anderson, ABC Managing Director, has recently shown a commitment to international broadcasting by launching an international version of the iview video on demand platform last month.

“ABC’s international services are a national asset and they have been for a vast majority of the ABC’s history. They’ve been connecting with Australians overseas, sharing Australian stories with the world, and letting our neighbours in the Indo-Pacific region know that Australia is a trusted friend. We’ve done that over multiple generations”.

Anderson commented that the international TV service, “ABC Australia”, is available in 80 territories across the Indo-Pacific region. ABC Radio Australia is available via FM relays right across the Pacific. Digital stories published in four languages reach people all over the world through web sites, social media and apps.

“The importance and relevance of international media is as important now as it was on the 20th of December 1939 when Sir Robert Gordon Menzies’ voice echoed across the ionosphere. The more things change, the more they stay the same. Misinformation and fake news are a threat to the rules-based order that we have across the globe”.

Pressure on the ABC and public broadcasting continues.

“Let’s not forget our foreign correspondents who report to and from the region: from the legendary Sean Dorney, Jemima Garrett, Natalie Whiting, Melissa Clarke, and Liam Fox”.

Anderson said “I believe, with the right commitment the ABC can offer even more to the region than what we do now. The question shouldn’t be whether we can afford to have an international media service, but whether we can afford not to”.

My thanks to the organisers for inviting me.

Tuesday, November 26, 2019

Beware of macOS malware

I've always felt pretty safe from malware by running macOS but recently three people I know have found that they have unwanted software on their Macs. In each case, they were tricked into installing software that claimed to be an update to Adobe Flash. I saw this scam recently and I think it was launched from an ad on the page. Here's a screen shot: yeah right, that sounds legit.

This works I think because we've all been well trained to keep Flash up to date.

The most obvious symptom of the infections I've seen is that your default search engine is changed from Google to Bing. I've no idea why that might be done but perhaps the browser extensions it installs is able to intercept your searches to Bing to better target ads at you.

To check for, or get rid of, this unwanted software, I recommend Malwarebytes which will let you do a scan for free and only asks for money if you want it to remain and keep scanning. This seems very fair to me.

I ran it on my machine and am clean, my neighbour had 17 bad things.

If you choose not to purchase then you can remove it via the Uninstall item in the Help menu.

The malware I've personally seen is "Adware" which seems to install browser plugins to show you more or different ads. It's annoying but the terrifying thing is that once on your computer who knows what it might get a look at.

Apple's macOS is getting more secure with more limits on what applications, including browsers, can access and I support this, despite occasional pain with apps that have to ask for lots of permissions.

Be very skeptical of popups on web sites, or even emails, that ask you to authenticate to install anything.

Friday, November 22, 2019

ESP32-CAM notes to self

Recently I purchased two ESP32-CAM modules from Banggood for under AU$10 each. There is lots of help on line including the excellent Random Nerd Tutorials site but I ran into a couple of problems. Here's the module I received:

I used the "video streaming face recognition" sample code but it reported that the camera found was not supported until I finally chose the CAMERA_MODEL_AI_THINKER.

Programming was done with an FDTI board running at 3.3V and powering the ESP32 board at 3.3V. When I disconnected the programming link and re-booted it would show "brownout detected". The solution was to set the USB serial board to 5V and power the board from the 5V line.

Finally I was up and running but the image was a terrible blur. Both boards were similarly bad. Close inspection showed that the lens is screwed into the sensor housing. In one case it was fully screwed in and glued. In the other case it was cross threaded and glued. Both were fixed with the help of some pliers.

The image quality is surprisingly good.

Face detection and recognition is pretty useless but amazing that it works at all on a tiny computer. The board also has a microSD socket and there's sample code to detect movement and save images to that card.

ESP32 is a great platform and is supported with the Arduino IDE or platformIO. I tend to get things going with straight Arduino and then move over to platformIO for better editing and features like code completion.

Sunday, November 10, 2019

MLA-30 active receive loop antenna

After reading a glowing review of the low cost MLA-30 active receive loop antenna, I ordered one from Aliexpress for just AU$55. Here are my initial impressions.

The components are of good quality and you get a generous run of coax.

The phantom power box is good (although the power LED is very bright). It's powered from a micro USB socket which might add to the noise floor.

I installed it on the balcony on a PVC pipe. I haven't done a good job of getting the steel wire to be circular but it's a good start. At least it has a low wind profile.

Comparison here is rather unfair on 40m as I have an excellent dipole. Here's reception on the dipole.

Here's reception on the loop. The noise floor is certainly higher.

Of course, the benefit of the loop is that it covers all of HF so beats the dipole on bands like 80m.

Here's a snippet of the ARNSW Sunday broadcast received on 80m using the loop.

Connectors are SMA which works well with SDR receivers. Here is a recording of 9MHz shortwave using the loop. It's not as good as my big dipole but I'm really impressed with what you can hear with a small loop on the balcony.

I'm impressed with this receive loop. If you have space for a full size dipole then that's the way to go but if you only have a balcony then this is a great way to listen.

G8jnj has reverse engineered the circuit of the MLA-30 here.

Check out this comparison from "Scanner and SDR Radio" between several receive loops, some much more expensive.

The author has replaced the co-ax with better stuff and used a larger loop.

Wednesday, November 06, 2019

13 Minutes to the Moon - interesting podcast

Thanks to talented friend Aidan Roberts, I've just listened to a fascinating podcast series from the BBC World Service called "13 Minutes to the Moon". You can get it by searching in your podcast player or downloading here.

The series tells the story of Apollo 11 but in particular examines the final descent to the moon and the things that went wrong, including communications failure and the 1202 (and 1201) overflow alarms from the flight computer.

As well as different versions of the audio from the mission, there are original interviews with some of those involved. I've read several books about the Apollo program and there was new material for me in this.

The music for the podcast is by Hans Zimmer and he's even interviewed about his memory of the landing. You've got to take podcasts seriously now that they have music composed by the guy who wrote themes for Interstellar and many others.

Friday, November 01, 2019

First experiment with LoRa transceivers

LoRa is a fascinating radio system for low power but long range digital data communications. Low cost transceivers claim a range of 15km. John, VK2ASU, has been working with these for a few months with an application involving reporting activity at a remote site.

I also came across LoRa when talking with the City of Ballarat for a GovHack story. They put a LoRa Gateway up on the town hall and are using it to collect data from all over town including things like rubbish bins reporting their fullness.

Here's my hardware setup. (Receive and transmit sides look the same).

I'm using cheap Arduino Nano Pros. They need to be 3.3V to talk to the LoRa Module.

The modules I purchased are RA-01 SX1278 on 433MHz. They were AU$8.67 each (but cheaper if you buy 2 or more). For starters I'm using ones with the little spring antennas and obviously better antennas help them go further.

With one at the extreme end of the house to the other here's the received packets.

So none are being lost. I'm not sure if the protocol re-sends if there's no ACK.

The Arduino library is one of the ones available right in the IDE. It is by Sandeep Mistry and the source code and documentation is here. To get started I wired up to Arduino Nano Pros using the wiring diagram from this excellent tutorial. The examples titled "LoRaSender" and "LoRaReceiver" work well and the only change is to set the frequency to 433E6 (meaning 433MHz) on each end.

There are many levers to adjust with LoRa and you can trade of data rate for range. John ASU advises that he uses these settings:

TxPower (20,20);
Spreadfactor (12);
Bandwidth (62.5E3);

I'm just using the defaults for now.

The tutorial mentioned that the 3.3V supply from the Arduino wasn't sufficient and that may be the case at higher transmit power levels, but for me it's working from the VCC line on the board which is powered by the USB Serial board I use.

The LoRa physical protocol

LoRa is a proprietary protocol but, naturally, this puzzle has led to some excellent work to figure out how it works.

On a waterfall, the spectrum shows what people call "chirps", that is the frequency sweeps rapidly up or down. Here's a picture from the GRCon16 video above by Matt Knight.

The receiver looks for the regular header at the top and uses that to sync up with the transmitter before the data packet begins. Note that the image above is vastly expanded. I've tried to view this with an RTL-SDR dongle in SDR# and all you see is very brief signals for each packet.