Is FT-8 Mode on Amateur Radio the Way Forward?

 

It is easy to see why FT-8 has become such a popular mode on the amateur radio bands, especially in these times of poor HF propagation and high man-made noise levels in urban locations. I have used FT-8 myself and worked 16 countries in an evening with low power and indoor antennas. This would have been a challenge using SSB, CW or PSK-31 but it was really easy on FT-8.

This did not take any great skill on my part. I tuned the radio, connected it to my computer via my Signalink sound card, started the WJST programme and waited a few seconds for calls to appear. A station was calling ‘CQ’ so I clicked on his call sign and the computer did the rest.

I question whether a FT-8 exchange really is a ‘valid’ QSO.  So let us examine a typical ‘QSO’ in detail. Exchanges on FT-8 are limited to 13 characters:

·         I see a ‘CQ’ call on the WSJT ‘Band Activity’ window from HA7xx. This tells me the station’s call sign and 4-charater Maidenhead grid (JN97). I click on his call and my computer automatically send a reply with my 4-charater Maidenhead locator (JO01).

·         He replies and sends me a signal-to-noise report (SNR). I automatically reply to this with his SNR report.

·         He acknowledges and the QSO ends, automatically. All that is left for me to do is to click ‘OK’ to conform the log entry that WJST has generated, automatically.

The information we have exchanges is:

• ·         Call signs
• ·         4-Charater maidenhead locator
• ·         Signal-to-nose ratios.

From this QSO, I know nothing about the other guy, name, where he is, type of equipment etc.  The 4-charater locator puts him (I don’t know if it’s him or her, but I will guess for the purposes of this post) somewhere in north-central Hungary. I only know he is in Hungary because I am familiar with the ‘HA’ prefix. Without this inference he could also be in southern Slovakia. FT8 does include a 'Free text' field of 13 characters so it is possible to send additional information during an exchange but I have seldom seen this feature used on the air. 

Surely, the Signal-to-Noise ratio is useful information as it is a very important property of any communications link? Actually it tells me very little about how my equipment is performing. For example, if a station tells me my SNR is +10db I know we have a good link and my equipment is performing OK. However, if a noise source, local to him, starts and raises his noise floor by 20db my SNR will degrade to -10db even though nothing at my end has changed.

SNR is only useful if it is used to manage a communications link, for example I could adjust my power, or bit rate to optimise use of the link. Unfortunately in standard FT-8 QSOs, SNR is sent right at the end of the QSO, just before ‘73’, so there is no opportunity, or reason, to adjust my equipment settings to optimise use of the link.

One thing that I am concerned about with FT-8 QSOs is: what would I say to a curious friend to whom I was demonstrating Amateur Radio? The friend might ask, where in Hungary is he? What’s his name? Etc.  and I would be unable to answer these or other reasonable questions, about the station I have just ‘worked’, and from this my friend might conclude that amateur radio is a waste of time.

It can be argued that FT-8, because of its increased sensitivity, identifies propagation modes that otherwise would not be seen (see Radcom March 2021). My QSO, which was automatically uploaded to 'PSKReporter', might provide a data point for academic research into propagation, but I doubt if anyone would be surprised that there is a path on 40m between UK and Hungary on a summer's evening.

I am not resistant to change in Amateur Radio, which must innovate to survive. I enjoy many older modes, particularly is they require a degree of skill, such as CW, PSK-31 etc, but I also enjoy innovative digi-modes, though not FT-8, as you will have gathered by now. I am not opposed to automatic quick-fire QSOs in appropriate circumstances. They have a place when transmission paths are short-lived or highly unstable, examples are EME or meteor scatter, but I see no useful place for these modes in main-stream HF communications.

I particularly like JS-8 mode. This uses a similar coding scheme to FT-8 and has some automatic click-and-work features. However it is not tied to FT-8’s 13-charater exchanges and so can do more; much more:

• ·         Unlimited QSO length so you can simply exchange reports or have a long chat
• ·         Work stations via intermediate stations (Relay)
• ·         Send, store and forward messages.
• ·         Adjust bit rate, transmit power etc. so you can actually make use of SNR information.
• ·         Beacon mode so you can see propagation changes in near real time.

Prior to FT-8, I was concerned about the move towards ‘Rubber Stamp’ QSOs, where we simply exchange fictitious ‘59’ signal reports and move on to the next QSO, started amateur radio down the road of irrelevance and FT-8 continues on that path. I would not go as far as to say it should be banned, but regular users might think about using other modes that permit substantive QSOs, require a higher skill level and are useful for exchanging real information such as could be used for emergency communications should the need ever arise.

As always, comments are more than welcome.    

SignaLink USB Digi-mode Interface

Digi-modes are attractive to me as they enable long-distance contacts with my low power and limited antennas. There are numerous computer programmes for the different modes and many multi-mode programmes. They all have one thing in common, it is necessary to make multiple connections from your computer to your radio

.

• Audio out of the computer,
•  Audio into your computer,
• ‘Press to talk’ to control when the radio listens or transmits.

This would require several cables and level settings to get satisfactory operation. To make matters worse, my old computer gave up the ghost and my new computer has no microphone socket, so I have to use an external sound card – more wires and more things to configure.

I use my computer for many things, not just amateur radio, so I cannot leave the amateur setup permanently configured. This meant the setup time was too long and too error prone for a quick go on digmodes. Then, my life changed! I came across the ‘SignaLink USB’ interface unit which has its own internal sound card and only requires two cables. (plus a couple of optional connections that I don’t use).

      

                  

Signalink Front and Back

First thing to say is that it’s small 80w X 100d X 40h (mm, in case you are wondering) which is entirely consistent with my station design philosophy. It only requires two cables:

• ·         From the unit to a computer USB port (supplied with the unit)
• ·         From the unit to your radio. These are bespoke cables that you buy when you order the unit if you do not want to make your own.

The SignaLink USB comes with comprehensive instructions and more help is available on the www.tigertronics.com web site if you need it. Documentation is good.

Setup is very easy. Internal adjustments are necessary to match the SignLink unit to your radio. This requires the unit to be opened by removing the four Allen bolts on the front of the unit and sliding the innards out. There are two ways to configure the unit:

• ·         Use the supplied jumper wires using the diagrams available on the supplied CD or from the www.tigertronics.com web site. This is the best option if you will want  to change radios often.
• ·         Fit a ‘plug and play’ jumper module for your radio that can be bought as an extra. This is the best option if you only want to use the SignaLink with one radio.

The process is very straight forward, but do read the instructions before you start.

This brings me to the only criticism I have – the Allen bolts are not metric size. If you are in Europe, this is a real pain because the old Imperial size Allen Keys (Wrench) are very hard to find here. One is supplied so don’t lose it! In my professional life, I would never buy equipment that used non-metric bolts etc. for use outside USA.  This would cause maintenance issues because the imperial tools, which were usually supplied, would invariably get lost or stolen.

Signalink Inside

Once the internal unit is back in the case and the Allen bolts fitted you can begin setup. This is very clearly described in the supplied documentation. This does involve messing around with the Windows sound controls, to set up the SignaLink internal sound card, but once this is done you seldom need to go there again. This is because the SignaLink has analogue volume control knobs on the front for transmit and receive so adjusting levels while operating is very easy.  

That’s it, you are almost ready to go. I leave the SignaLink connected to my radio so all I have to do is connect the SignaLink to my computer and switch it on. The SignaLink is powered from the USB port so no need for an external sound card or power supply.

Start your digi programme and select “USB Audio Codec” for the input and output. Check the receive signal level and adjust the RX control on the front of the SignaLink. Send a tune signal and adjust the TX control on the front of the SignaLink for the correct level (then back it off a fraction of a turn!).

I have tested the Signalink with the following software:

• ·         MultiPSK – the Swiss Army knife of digimodes.
• ·         WSJT (FT-8, WSPR etc.).
• ·         SeaTTY – for receiving weather reports etc.
• ·         WinWabler.

It works fine with these applications, and I don’t doubt, with many others as well. It is now very easy to get on the air and so I am able to do digital sessions even when time is limited.

As the Signalink unit is small and simple to set up, portable digital operation such as a SOTA expedition, with a tablet for example, is quite feasible. Unfortunately, at the time of writing, UK is in lockdown for the CV-19 pandemic so I have not tried this yet.