Friday, July 23, 2021

The best digital mode for weak signal keyboard to keyboard QSOs?

Since moving from Sydney to Melbourne I've wanted to be able to chat with my Sydney friends but have wondered about the best mode to use for this from the huge list in fldigi.

Stephen, VK2BLQ, and I have been running WSPR and watching the signal to noise ratio for band openings on 40m. Today looked like this:

When WSPR shows an SNR of better than -10db we try for a contact. Until today I had thought that the best mode would be one of the wide modes such as Olivia 16/500 and we tried that for a while. We could hear each other but could not decode.

On a whim I suggested switching to good old BPSK31 and suddenly we were talking!

I find this rather puzzling and would welcome an explanation. Some commentators compare digital modes and rate BPSK31 very poorly compared to other modes. Local hero David Rowe has been doing some work on data modes for HF radio and I intend to try out what he's been working on.

K8JTK has quite a nice writeup of different modes here and we plan to test QPSK31 over BPSK31 soon.

The noise level here is distressingly high. A solid S9 of broadband noise. I've tried a loop antenna but it's similar.

Update: Good contact on Saturday

I received VK2BLQ at -10 on WSPR so we had a good contact using BPSK31 just now (local time 10:30).

For a while we had perfect copy (some errors are Stephen's typing) but then signals faded and I have a storm coming in.

We experimented with sending PSK carrier and measuring S/N and IMD. Stephen receives me with S/N 25db and IMD of -22dB which seems pretty good. I don't get him as well but we did determine that him reducing power a bit gave rise to a better IMD.

Noise levels for both of us are down today so that might be the explanation rather than just improved conditions on 40m.

Wednesday, July 21, 2021

Awesome Amateur Radio link list

Mirko Caserta has started a useful list of Amateur radio links. There's loads of these around the web but this one is on GitHub which means that contributors can fork and send pull requests to edit or add content. 

Mirko clearly favours alphabetical order.

The topic areas at the time of this blog post are:

  • Antenna
    • Analyzer
    • Balun
    • Tuner
  • Band Plan
    • CW
    • Digital Modes
    • Interface
    • Misc
    • Italy
  • Organizations
    • Global
    • by country
      • Australia
      • Canada
      • Germany
      • Italy
      • Japan
      • New Zealand
      • UK
      • USA
  • Propagation
  • Rig
  • Satellite
  • SDR
  • Shopping
So clearly there's lots more to add. I've contributed some Australian content and Mirko has granted me edit access so I'll keep going.

Sunday, July 11, 2021

Røde Wireless GO II microphone for iPhone review

Good audio with bad video is generally acceptable. Good video with bad audio is never OK.

In the past I’ve used the excellent Sennheiser radio mics but I’ve been tempted away by the prospect of digital output. My daughter uses the Røde Wireless Go kit and recently I purchased the Go II.

A third of the price of the Sennheiser but with superior features. Note that with the GO II you get two transmitters.

The GO II claims a range of 200m line of sight. I don't doubt this. Transmission is digital at 2.4GHz and seems highly resistant to interference. Compared to the analog Sennheiser system which needed an RF scan to avoid interference from other mics.

The GO transmitter and receiver are in a small 45.3mm square box with a clip that also conveniently slides in to a camera hot shoe.

The transmitter has a decent mic built in and comes with a fur wind shield. A lavaliere mic can also be used but is a separate product.

You can use just one transmitter and have it appear on both channels. Two transmitters can be used with one on left and the other on right (for later mixing). Transmitters can be muted.

Transmitters and receiver come paired although the instructions are rather brief.

Features I didn’t expect:

  • The two channels can be kept separate or mixed down to mono
  • The transmitters can record 40 hours of backup audio locally
  • You can record a second track at -20dB in case the level is so high that the main channel clips
  • The receiver has a USB-C port that, if plugged in to a computer, comes up as a sound card
  • Analog output from the receiver can be attenuated in three big steps or much smaller steps if desired.
  • There is an app, Rode Central, for iOS, macOS, Windows, & Android
  • When using digital output you can use a headphone to monitor reception

Connecting to an iPad pro is easy - a standard USB-C cable does the job and audio apps including Voice Memos and the Rode Reporter app switch input to use the device. Connecting to an iPhone does not work with standard USB-C to Lightning cables that you normally use to charge or sync. A special cable known as a Lightning Accessory cable is required and as far as I can find so far only Røde makes one called an SC15 cable.

Here's a little test recorded with an iPhone.

iOS is not great at showing use of external USB audio inputs. Generally, just plugging in an external audio device sets recording apps to use it but I read that in some cases you must launch the app first and then plug in the external audio input to get it to be used. I wish we could see all audio inputs and switch between them. In any case, test carefully before an important recording.

One small usability irritation is that the power on button, obtusely marked with a “Ø” symbol, is on the opposite side to the other two buttons on the receiver which makes it a bit difficult to press without pressing other buttons. The square form factor is a bit strange, particularly for the transmitter which clips on to a shirt with the mic pointing sideways. 

I can see the digital transmission at 2.4GHz:

I haven't pulled mine apart but the FCC listing shows a nicely made board:

Since Apple has started seriously messing with ad tracking I notice this rather weird targeted ad for dog food as a result of buying the Lightning accessory cable.

LOL. I really like this wireless kit and if you get the lightning accessory cable it makes a very compact video recording setup with excellent audio. The kit comes with a nice cloth pouch, two USB-C to USB-A cables, and three wind socks. There's not much documentation with the product but the online learning hub is pretty good.

Røde is an Australian company and from what I can see they've done fantastically well around the world. 

Friday, July 02, 2021

XIEGU G1M portable SDR HF Radio review and notes

After my recent SOTA experience I've become interested in more compact and portable QRP gear. A radio that's getting good reviews is the Xiegu G1M

As you can see it's almost dwarfed by the SignaLink adapter.

I bought via eBay and paid AU$354 plus shipping. (Prices vary a bit I notice).

The radio comes with a rather muffled microphone, a power cable (to open wire), a serial USB cable (for CAT and software updates).

A printed manual was included but it's not as up to date as the one available from the manufacturer.

The G1M puts out 5W sideband or CW and can also receive AM. It's general coverage receive and transmits on 4 bands: 80m, 40m, 20m and 15m.

It runs on 12-15V and works fine on a 3S LiPo battery from my drone days. Running on 13V it draws 400mA on receive with no audio and peaks at 2A on transmit.

Here's a backyard SOTA practice with a simple vertical on a squid pole matched with a Z-Match.

There is an active community discussing the radio on

Mine came with firmware V1.06 but there is a new version 1.07 available. (For some reason it isn't yet on the Xiegu site here). Firmware is uploaded over a serial port using XModem. I used the go language uploader from Dale Farnsworth on macOS to upload the new firmware. 

You need to un-rar the file to get a .xgf file to upload.

The first two attempts stopped uploading before completion and I thought I might have bricked the radio but a third attempt worked.

As others have noted, the version still displays V1.06 Oct 22, 2019 but it's clear that the CW bandwidth is now narrower so it has changed.

There are several stickers to discourage disassembly but I couldn't resist. You need to take off the volume knob and remove the nut.

On the back, remove the nut from the BNC socket.

There are two thin co-ax links that need to be unplugged and two flat cables that can be released by flipping up the little plastic clip on the board end.

Interesting that there's space for another low pass filter on the board.

I've used the radio for WSPR reception and there is no reported drift. 

I'm quite impressed with this radio. It is an SDR and has a tiny little spectrum display that is actually handy for seeing signals. Reviews on eHam are generally good. There are a couple of reports of DOA units but mine works well and construction is of excellent quality.

Saturday, June 19, 2021

ATS-20 Si4732 receiver firmware update

I recently purchased a nifty shortwave and FM receiver from AliExpress built around an Arduino Nano and Si4732.

I pulled mine apart to try to see if there was a label that would provide a clue about which version to write it it - there isn't. A tip: you can just undo the top screws front and back to get the lid off. Watch the speaker connected by short wires

On power on, it displayed V1.1.5 of the library by PU2CLR. After upgrade it now shows 3.04.

I followed the instructions on but used Arduino 1.8.13 on macOS just fine.

Basically the steps are:

  • Select Arduino Nano
  • Select ATMega 328P (Old boot loader)
  • Install libraries:
    • SI4735
    • Tiny4kOLED
    • TinyOLED-Fonts (it's a dependent)
As well as plugging in to the Nano I had to power on the radio to program it.

The source code is available here. For my hardware, I found the version titled "SI473X_ALL_IN_ONE_OLED_RDS_CHINESE_V3" was the one that matched the buttons on my front panel.

In the source code of the sketch there are some settings to adjust if you like such as default volume.

Before upgrade here's the splash screen:

After the update it looks like this:

The display in operation is a bit different too.

It's quite a sensitive receiver and sideband works pretty well. Here's an example.

There is no bandpass filtering on the input so it would probably be overloaded if connected to a broadband antenna. It's wonderful to have the source code to play with - all credit to PU2CLR.

Thursday, June 17, 2021

My first SOTA - cold and wet but not disappointing

Paul, VK3HN, kindly invited me along to a Summits On The Air (SOTA) activation today at Mount Disappointment close to Melbourne.  

The weather did not look promising but we decided to risk it and while it was rather damp and cool, it could have been worse. 

David, VK3KR, generously drove and Owen, VK3EAR cleverly opted not to come and stayed at home to monitor.

I took a loop antenna and an IC-705 with external battery. Paul had two home brew rigs and used an end fed antenna. David was on 2m with a home built beam.

Paul has created a video that captures the day very well:

Here is Paul's latest home brew rig. It is a crystal locked CW transceiver. I really admire his construction and recommend his video about how he hand makes printed circuit boards.

The mountain was beautiful but there was intermittent rain and the temperature fell to about 7C. We were all soaked through by the end of the outing.

SOTA is a great idea in that it encourages bush walks to mountain peaks with a bit of ham radio activity. David was the most successful and even had a contact with Peter, VK3YE on 2m.

Things I learned:
  • Use pencil for the log - my ink ran in the rain
  • Less weight is good - even though the loop was pretty light an end fed wire would be better
  • Don't take a chair - I thought I was being clever by bringing a folding chair but it turned out that there was a picnic table there anyway so that was unwanted extra weight to carry.
I'm looking forward to trying this again in better conditions.

Monday, June 14, 2021

Games on Netflix? My comments on ABC Download this show

Topics on ABC Marc Fennell's Download This Show were the Apple Developer Conference announcements, Facebook's ban on Trump, paying for extra Twitter features and the prospect of renting games on Netflix. Here's a video segment:

The full radio version of the show is available here. I enjoyed meeting Dr Emily van der Nagel who has done some very interesting research into social media platforms.

A book I mentioned in the radio show is Influence by Robert Cialdini.

Saturday, May 29, 2021

Wonderful new SDR design described by Ashhar Farhan

A video of a presentation by Ashhar Farhan, VU2ESE, has been posted and I can't recommend it highly enough. He describes a new design for what looks to be an easy to build SDR based around a Raspberry Pi. Along the way, Ashhar also clearly explains many of the key parts of how a Software Defined Radio works.

The paper that goes with it can be viewed here. Thanks to Stephen, VK2BLQ, for drawing my attention to this and for Bill at Soldersmoke for the link.

Today is a bit sad for me as I'd hoped to be going to MayHam at Wyong but due to a pandemic lockdown in Melbourne I'm unable to leave my home.

Thursday, May 20, 2021

A visit to Paul Taylor, VK3HN.

I have been a fan of Melbourne ham radio home brewer Paul, VK3HN's blog and YouTube channel for some time. We met a few years ago at Peter, VK3YE's QRP by the Bay but I discovered that he lives not too far from my new home in Thornbury so I invited myself over for a visit.

Paul's blog is of a very high standard, well written, with extensive technical information about his projects. In recent years, projects have been demonstrated and explained with well made videos as well.

Projects cover the spectrum from small portable CW rigs all the way to a high power AM transmitter using the efficient Class E mode.

There's a few things that stand out to my eye - Paul tackles complex projects with a logical modular approach, often building on tried and tested standard designs but without fear of trying more challenging designs. 

Circuit boards are manually etched using the resist pen method.

Most striking of all are the cases which are custom fabricated from aluminium angle stock and sized to snugly fit the enclosed circuitry.

Thanks Paul for an entertaining and educational evening tour of the shack.

Incidentally, you can hear more from Paul at HRDX via SolderSmoke and a terrific interview on QSO Today episode 298.

Sunday, May 16, 2021

Low cost loop antenna for 40m from VK2BLQ

Stephen, VK2BLQ, and I test the Sydney - Melbourne path using WSPR and we have been comparing our noisy external antennas with loops in various positions. 

Today he sent details of his latest loop made mostly with bits of Bunnings.

He writes: "The loop is approx. 900 mm diameter as it was a 3m coil of copper from Bunnings, when it was cheap.

I let it run on 40 m wspr yesterday and this morning and pretty much was only received along the east coast but not by Peter. Only the wire antenna which is 3 m above the loop reached USA Canada and all over other places.

WSPR is ok but the only real test is for two way communications; I could hear VK3XU at good  level this morning and VK2ARZ a bit later. I need a small changeover switch between keyer and key.

The tuning capacitance is the double sided pcb, the actual value of capacitance depends on the thickness and type of the fibreglass, so it was a case of measuring a piece and cutting off small pieces until I can see the minimum swr on a Nano VNA. The PCB has a coat of lacquer and soldered to the loop, it probably is not too resilient outside.

The Coupling loop is a 1 m length of RG 11 75 ohm TV cable with only the braid and foil shield being used. It is longer than the customary 20 %, and perhaps that is why the Q is low.

Some heat shrink to cover the joints and definitely only temporary.

Next version will be a 6 m perimeter octagon as I have four 1.5 m lengths of copper. I read somewhere that the capacitor should be at the bottom with the feedpoint at the top for a better angle of radiation. This is possible if I re-solder the PCB capacitor".

Stephen is certainly covering Australia on 40m WSPR but oddly missing the bit of Melbourne where I am located.

We are travelling to MayHam at the end of the month and if it fits in the car we'll bring it along for the Home Brew display.

Saturday, May 08, 2021

Attended a rally in support of the ABC

Josh Frydenberg, Federal Treasurer, did not attend the meeting at Hawthorn Town Hall - despite a respectful invitation - but about 450 people did. A letter from Mr Frydenberg was read in full to the assembled audience prompting some laughter and astonishment as he repeated the Coalition’s position that there have been no cuts to the ABC while also arguing that all media hurting and so should the ABC.

Speakers at the evening included ABC Friends’ President Michael Henry; past Chair of the ABC Advisory Council and Director of the Victorian College of the Arts, Professor Andrea Hull; Professor Ed Davis AM; Vice President of the Media Entertainment and Arts Alliance, former ABC journalist, Karen Percy; and Former ABC journalist and ABC Alumni member Jim Middleton.

Tosca Lloyd showed a film produced by GetUp titled “Murdoch and Morrison vs the ABC” which drew together the broad community support for the ABC and illustrated the concerted campaign by Murdoch media and the Institute of Public Affairs (IPA) to weaken or even privatise the ABC.

The panel discussed the impact of cuts to the ABC experienced so far including cuts to key programs and staff levels during the government’s time in office. More subtle attacks on the ABC including efficiency reviews and frequent criticism of program makers in Murdoch media were also discussed.

A video of the event is available.

It was a very professional, focussed and well-run event. It was my pleasure to work in a small way with Michael Henry and in particular key organiser Marcus May in the preparation of the event. My thanks to Jim Middleton for stepping up to speak and be on the panel.

Thursday, May 06, 2021

Talking crypto on the Vertical Hold podcast

It was my pleasure to be a guest again on the Vertical Hold podcast this week. 

In this week's episode: "What’s the tech behind BitCoin’s booming rivals like Ethereum? What are ‘smart contracts’? Why would you build an AI bot and give it dementia? Guests Access Informatics’ Peter Marks and Dementia Australia CEO Maree McCabe".

Hosts Adam Turner and Alex Kidman run a tight ship and it was fun for me to experience Zencastr for the recording which records each guest locally in high fidelity and then uploads their audio. 

Sunday, May 02, 2021

Got the first AstraZeneca Vaccine at Melbourne Exhibition Centre

Today I became eligible for a COVID vaccine so I was keen to get it done. The web site indicated that my closes mass vaccination centre is the Melbourne Exhibition centre. The site said I could book an appointment or just turn up and there was a 15 minute wait. I decided to be a "walk-in".

Arriving at the address, I could see the building but no visible signs or people. There are some signs but they are on the ground.

It turned out that the entrance was on the side opposite the Museum.

The queue was short but slow moving. There was no sign to confirm what the queue actually was. A bloke in the queue before me joked that he was here for the beer festival (which was on the last time he was here). After a while staff came out and asked for people who had booked to come out and go straight in, even if their appointment was hours in the future. 

At the door we were temperature checked and given masks.

Once inside, there are more queues. We were advised to have our Medicare card handy.

At the desk we were also asked for photo ID so people had to dig through their purses and wallets.

After the interview we were then directed to a mysterious system of rows of spaced chairs, then on to a single row of chairs and finally to a booth with a person to give the "jab". 

The injection was completely painless for me. Next jab is due in 12 weeks, you can go as early as 4 weeks but 12 weeks is better.

After the jab you sit for 15 minutes before leaving. All staff I interacted with were efficient and professional.

Lessons for consumers:

  • Booking is a fast track to the door
  • Bring your Medicare card and photo ID
  • Bring information on any medications you might be on such as blood thinners
Suggestions for the vaccination centre:
  • Put up a big sign at the address you give directing people to the queues
  • Have signs on the queues saying what they are: "walk-in" vs "appointment"
  • Tell people they need to have Medicare and photo ID ready
Side effects

My arm started feeling warm almost immediately. A few hours later it's a little sore and I have soreness under my arm. One day after the first jab I felt general muscle soreness. Took paracetamol. Felt very tired and had a sleep for a few hours in the afternoon. Day two, arm still sore but no other discomfort.

Friday, April 30, 2021

Forced to wait over four hours to get through to Qantas to use a credit

A flight I booked last year with Qantas was cancelled by them due to pandemic lock-down and so I have a credit. Now that things are open again I wish to use that credit. It's not easy... The web site told me I had to ring them.

I've rung a few times in recent months and been informed that the wait time was over two hours so I gave up. Today I decided to stick it out as it didn't give any information about the wait time. I interpreted this lack of estimate as a sign that it was going to be quick.

After more than two hours I started trying to contact them via Twitter as this seems to have worked for some other people in my situation.

Facebook looked like it might be a more efficient way to contact them as they say this:

Alas, "7 days" doesn't seem to include today.

I tweeted a thread of comments but didn't get a response. 

This is what you have to listen to:

Finally, after more than four hours I got to Eric. A very nice operator who was able to fix me up.

I value my time and this punched a big hole in my day. My guess is that many people are not able to invest this much time in redeeming their flight credit so Qantas gets to keep it. This reeks of being a "dark pattern".

Wednesday, April 28, 2021

Talked about monetising Podcasts on ABC Download This Show

Great to get back to a studio for these shows at last.. Although I look like I'm coming from a black void compared to my co-guest Meg Coffee.

On the TV bit we talk about Apple's announcement of support for Podcast subscriptions.

The podcast version is out (and it's free!) The radio version is available here. I had a question from someone asking why my video quality was better than the others. This episode was the first time I've appeared from the ABC Melbourne radio studio where they have a Sony AX53 camera in HD mode.

Here's the view from my perspective.

Tuesday, April 20, 2021

Appeared as a guest on ABC Sydney Focus talking about 5G and the 6G controversy

This week it was my pleasure to be a guest again on Cassie McCullagh's ABC Sydney show called Focus. It's always easy to work with these folks.

The discussion ranged over a variety of topics including my skepticism about the consumer benefits of 5G, the controversy about the early specifications of 6G (don't panic, it's not due until 2030). We also talked about how much we all value a fast and reliable NBN after our shared experience over the past year.

You can hear the program here.

Thursday, April 15, 2021

Monitor multiple digital modes simultaneously with Hermes-Lite and SparkSDR

The Hermes-Lite 2 continues to impress. I've now been turned on to the wonders of the cross platform SparkSDR software which open up multiple receivers, running different modes, and (if you have WSJT-X installed in the normal place), it decodes. Here is my setup under Ubuntu with receivers for WSPR, FT8 and JT9.

My thanks to Robin, G7VKQ, for bringing this to my attention! 

Tuesday, April 06, 2021

Farewell to the van

The van has been an entertaining project over the last few years. A 2000 Toyota Hiace with 411,000km on the clock.

We have travelled up and down NSW many times and made the big trip across Australia to Perth.

Despite a few mechanical problems it has never let me down. 

Now though, each time I register it expensive repairs are needed. The time has come.

Highlights for me have been listening to ham radio in remote, and quiet, locations and just sleeping in the van - particularly when it's raining.

Farewell Morrison.

Tuesday, March 30, 2021

RAAF 100 year flypast in Canberra

I'm not a plane geek but Kevin, VK2KB, talked me in to a trip to Canberra to watch a spectacular flypast by the RAAF to celebrate 100 years. Here's what I saw:

Apologies for some wobbly framing. I think I got better as it went along.

Thursday, March 25, 2021

Officially an "old timer"

Old friend Nigel, VK3DZ, kindly invited me along to a meeting of the Radio Amateurs Old Timers Club. To be eligible for membership one must have held a license for 25 years. As I got my license in 1978 I'm well within the range so I applied to join and, after careful reference checks, was accepted.

Bill Roper, VK3BR, efficiently processed my membership and sent a nice welcome letter, an impressive certificate and a recent copy of "Old Timers' News" which is a very professionally produced magazine.

Today's meeting was a catered lunch at the Bentleigh Club followed by an excellent talk about Summits on the Air (SOTA) presented by Peter, VK3PF. 

I was surprised by the number of attendees that I already knew from the past and we had a wonderful chat over a hearty lunch. Chatting with Dave, VK3ASE, about being "old timers" he commented that inside he feels about 17 years old.

Also in attendance was prolific home brew author Drew, VK3XU, who I had the pleasure of visiting recently. He called me out on the picture of his home repaired glasses - I explained that it's one of my favourite photos from that day.

Great to catch up with Peter, VK3YPG and John, VK3EGG. Thanks to the organisers and all involved.