Data Modes
Mike Richards G4WNC reminds us that the hobby provides opportunities for us to self-train, make friends, share knowledge, help in disasters and more.
Mike Richards G4WNC reminds us that the hobby provides opportunities for us to self-train, make friends, share knowledge, help in disasters and more.
During my recent club talks, there have been several discussions about FT8 and its role in amateur radio. One experienced operator summed it up rather well as “A great way to fill up your logbook!” This is not a criticism of Joe Taylor’s development team or the performance of the mode, it is just a reflection of the way it is used. FT8, like all the WSJT-X modes, is primarily designed to support weak signal operation. In addition, FT8 and FT4 have been further extended to provide improved performance for rare DX stations and contest work. However, when I tune around the HF bands, the FT8 signals are usually the strongest on the band! While the popular FT8, FT4 and WSPR modes provide an excellent indication of the propagation from your station, there is no real communication or knowledge sharing taking place. The net result is that operators are mainly working in isolation. No new friendships are being formed to help us understand and integrate with other cultures or expand our technical knowledge. I recently extracted some QSO data from PSK Reporter and discovered that, out of a sample of nearly 1.3 million contacts, 99.66% were using minimum information systems like FT8. That leaves just 0.34% using open systems such as PSK31, RTTY, etc. I fear that many of those were also rubber-stamp QSOs.
That brings me on to my next point. Although not often required in the UK, one valuable role for amateur radio is to provide communications in times of emergency. In the UK, emergency support is coordinated by the Raynet organisation: www.raynet-uk-org
While we don’t have the number of natural disasters experienced in many countries, we should still be ready. There is one huge vulnerability that could strike at any point, and that is the internet. Our lives are becoming inextricably linked with the internet. Our money is online, as are our health records, our phone systems, TV and even our logbooks. So far, there have only been a few relatively minor glitches in the internet, typically where a bank system falls victim to a bug and goes down for a while. However, there are industrial scale, state-sponsored, hackers out there who are constantly looking for ways to hack into our networked systems. These hackers are extremely clever and do not advertise their presence in a system. A good example can be found in what’s known as the Lazarus Heist. This was a state sponsored hack of Sony Pictures that happened a few years ago. When triggered, that attack launched unreleased films on the internet and exposed thousands of sensitive internal emails. These had a damaging effect on both executives and employees.
When infiltrating a large system like Sony, the hackers only need to find a route into one computer or device. Once in, they will silently probe around the network to find more important computer systems to hack. As they move from computer to computer, they often clean up behind, leaving little trace of the previous infection. The same group has
carried out other high-profile attacks, such as the attempted theft of £1billion dollars from the National Bank of Bangladesh. They very nearly got clean away with that one. If you want to learn more about these organised attacks, BBC Sounds have an excellent podcast running called the Lazarus Heist.
While I’ve reported a couple of specific examples here, you can be certain that all developed countries have teams that are finding ways to infiltrate each other’s systems. The point here is that the internet is vulnerable, but we have yet to experience how disruptive an attack could be. It may be that our national defences are up to the job and we don’t need to worry. However, amateur radio could have a significant role by providing an alternative digital network. We won’t be able to match the capacity of the current network, but we could still provide useful capacity.
However, we need to be prepared. That preparation could be experimenting with microwave equipment to provide high speed data links via hill tops. We could also be looking at text messaging systems using adapted data modes like FLMSG. By tackling these projects, you will extend your technical knowledge while collaborating with others to provide a useful service. Radio clubs are an ideal catalyst for this type of development work and it would be great if a few of the more active clubs could get the ball rolling. As an individual, you can help by giving FT8 a break and using more free-form modes such as PSK31 and MFSK. One thing is for sure, if we suffer an attack, FT8 won’t be much use!
Practical Ideas
If you want to build a wide bandwidth digital link, you need to be working with microwave or optical links. The best place to start looking for guidance is the UK Microwave Group (URL below). The UKuG have all the knowledge and contacts you will need to get started with Microwave work. Membership is just £6 a year and they even have loan systems and hard-to-find components available for members. http://microwavers.org
For text messaging, try experimenting with FLMSG, Fig. 1. This is a messaging system that works with FLDIGI and is used by US amateurs to support their emergency communications systems. Also included in FLDIGI are a range of MFSK modes. Another popular and versatile messaging system is WinLink as it provides a Global email service that can operate without the internet, Fig. 2. Full details can be found here: http://winlink.org
Don’t forget about PSK-31, 63, etc. as the PSK mode makes for an excellent free-form messaging system and is remarkably resil
ient. JS8CALL is also worth a look as this is an adaptation of FT8 that enables free mode messaging, Fig. 3. It’s a slow system but can get through very poor conditions.
In my next column I’ll go into more detail and show you how to use some of the other data modes.
ClubTalks Available
One of the great things to come out of the pandemic has been the widespread adoption of Zoom conferencing. Although originally started to help clubs keep running, many have realised that Zoom opens the possibility to invite speakers from far and wide at little or no additional cost. Under normal circumstances, the range of available speakers is limited by travel distance but Zoom has cleared away that barrier. Several clubs have asked me to give talks over the past year, so I’ve created a range of talks that are now available for other radio clubs to call on. I make no charge for these talks and you can contact me via mike@ g4wnc.com. Here’s a summary of my current talks:
Pictorial Introduction to Data Modes: This talk is designed for those who are either new to data modes or are considering starting data modes. Topics include: What are data modes, Why bother, How they work, What do you need and Connections. The talk concludes with some FT8 operating techniques and a look at the future of data modes.
SDR Technology without Maths!: This is a look under the bonnet of SDR transceivers where I show you why IQ signals are important and explain how they work. The talk uses illustrations to show how SDR systems operate and avoids maths where possible. I cover a variety of SDR techniques and conclude with a look into the next generation of SDRs.
Raspberry Pi in the Shack: A run through the Raspberry Pi range, including the new Pico microcontroller. I cover several amateur radio orientated projects, including the RadioBerry direct sampling transceiver.
Introduction to Digital Mobile Radio: Intended for those new to digital voice. This talk explains the challenges of digitising speech and shows how the popular systems work. I also provide some jargon-busting explanations to help you make sense of digital mobile radio operation.
Affordable RadioBerry
Regular readers will know that I’ve been a keen follower of the HermesLite 2 and RadioBerry projects for some time. The RadioBerry is a small SDR transceiver board that mounts on top of a standard Raspberry Pi computer.
The RadioBerry has a great pedigree because it’s derived from the HPSDR project that was the foundation for the Apache ANAN line of transceivers. The key difference between the Hermes and the Hermes Lite is the repurposing of a cable network transceiver chip to replace the 16bit ADC (Analogue to Digital Converters) in the original design. The result has been an excellent, direct sampling, SDR transceiver (12-bit ADC) with continuous coverage from LF to 30MHz.
The Hermes Lite design is available as a fully assembled module from Makerfabs. There are three parts to the transceiver. The first is the main Hermes Lite 2 module at $225.70, then you need the Hermes Lite 2 N2ADR filter board at £52.70.
There is also a sign-written case available for just $16.90. When assembled and connected to one of the popular SDR software packages like SDR-Console, you have an all-band 5W SDR transceiver that can run two or more receivers anywhere in the LF-HF bands. The Hermes Lite 2 has been used as my main transceiver for the past couple of years.
The RadioBerry is an adaptation of the Hermes Lite 2 that uses a Raspberry Pi 4 to provide the networking and processing power, Fig. 4. Although the full design files and PCB layouts have been shared via Github, home construction has been the only way to get a working transceiver. I have a hand-built version, but it was not an easy task because most of the discrete components are 0603 size (1.6mm x 0.8mm) and then there’s that large FPGA to solder!
The construction problem is now solved because one of the Chinese manufacturers has started producing ready assembled and tested RadioBerry boards. You can find them on AliExpress (URL below) and the cost is around £72 with free postage. http://bit.ly/radioberry
I purchased one to check out the quality and It’s performing well. I’ve shown a photo of the new board in Fig. 5. The designer of the RadioBerry project and several people on the user group have purchased the assembled version and all have reported good results. The designer has also developed what he’s calling a pre-amplifier module, which adds a 5W PA plus transmit/ receive switching and mounts on top of the RadioBerry, Fig. 6. This module is currently only available for self-build from Github files but, hopefully, it will go into production soon.