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The Rise of Digital Modes: The Changing Face of Ham Radio

Change in Amateur Radio operation modes often comes slowly due to the need to change equipment. Two major changes in the history of Amateur Radio that vividly illustrate this include the transition from spark to CW and the move from AM to SSB (single sideband). Both required a fundamental change in the radio equipment that Hams used.

These types of hardware changes usually happen more gradually due to the costs of acquiring new equipment or modifying existing equipment through the use of add-on devices. If we take a look at changes/trends that have occurred rather quickly, we see many of these required the addition of simple accessories rather than major equipment. A good example is the rapid explosion of Packet Radio in the early 1980s. Most Hams already had 2-meter FM transceivers; the addition of the TNC (Terminal Node Controller) and a personal computer allowed for quick adoption. From a few experimenters in 1978 to “almost everyone,” Packet Radio adoption was almost an overnight phenomenon.

Although the use of Packet Radio dropped off dramatically, the personal computer that snuck into the radio shack as part of the process stayed around and got much more sophisticated and powerful. The shack computer was soon integrated into rig control as well as logging and contesting software. We take these things for granted in today’s shack, and even though they have changed how we do many things, they have also fundamentally changed many of the modes we use to make Amateur Radio contacts. No longer did big changes in modes require hardware retrofits as new mode after new mode has been developed utilizing the PC and so-called “Digital Sound Card Modes” (DSM). Some DSMs are very different, but some are simply software replacements for historical hardware modes. RTTY is a great example. During the pre-computer years, RTTY was accomplished through the use of big, heavy and loud electromechanical teleprinters. This made RTTY a rather esoteric mode practiced by a minority of Hams willing to make the investment in these machines. Today, RTTY is available via simple software programs or even built directly into modern radios like the ICOM IC-7300, Yaesu FTDX-3000, or Elecraft K3S.

Weak Signal Modes Come on Strong

The “Digital Sound Card Modes Revolution” is seen in the proliferation of new modes over the last few decades, including PSK, Olivia, Throb, Hellschreiber, and many others. Currently, the combined activity on all these modes is dwarfed by a group of three modes (JT65, FT8 and FT4) that make up the WSJT weak signal modes software package by Joe Taylor, K1JT*.

Many people have debated the positive and negative effects of WSJT (Weak Signal/Joe Taylor) modes, but few would disagree that the effect has been a seismic and almost an overnight phenomenon. The switch from majority AM to majority SSB took over a decade, but the wide use of FT8 took less than a year! Looking at my own log, I can draw a few conclusions on changes in my HF operation modes that I think also apply to many other Hams.

The two charts below show the results from Clublog.org where the sample size is a little larger (over 500,000 QSOs)! If you are interested in taking a deeper look at Clublog mode data, G7VJR and LA8AJA have very informative websites.

I first started using JT65 in March of 2016. By the end of the year, it accounted for 26% (1,109 of 4,168) of my QSOs. I started using FT8 the week K1JT released it to the public in July 2017. With only six months of FT8 operation, it still made up almost 39% of my year’s total QSOs (2,085 of 5,376). In 2018, FT8 accounted for over half of my QSOs (4,417 of 8,722). FT4 was released in April 2019 and has accounted for almost 19% of this year’s QSOs as of September 2019 (1,362 of 7,189).

When I started using JT65 in 2016, it had already been in use for a few years. Released in 2003, JT65 was intended for extremely weak but slowly varying signals, such as those found on troposcatter or Earth-Moon-Earth (EME, or moonbounce) paths. It can decode signals many decibels below the noise floor, often allowing amateurs to successfully exchange contact information without signals being audible to the human ear.

Like the other WSJT modes, multiple-frequency shift keying is employed; unlike most other Ham Radio modes, messages are transmitted as atomic units after being compressed and then encoded with a process known as forward error correction, or FEC. The FEC adds redundancy to the data, such that all of a message may be successfully recovered even if some bits are not received. Because of this FEC process, messages are either decoded correctly or not decoded at all, with very high probability. After messages are encoded, they are transmitted using MFSK with 65 tones (hence the name JT65).[1] The big change came when more and more Hams began using JT65 on the HF bands.

The general Ham population soon learned that if they could be patient (patience was required as typical QSOs took four minutes to complete), they could make long-distance contacts even with moderate to poor conditions and low to modest power. QRP operators like myself found ourselves calling CQ and getting multiple replies from DX stations!

There were still three big problems. First, it took a long time to make contacts. Second, it required more than a little computer knowledge. Third, it took some tinkering to set up the software and sound interface. The first issue (long QSO time requirement) was not a problem for me since I was doing a lot of writing, spreadsheets, and other computer work so I was able to run JT65 in the background while I multitasked on the computer. The second problem was mostly solved by many Hams being proficient with computers and software. Fortunately, their willingness to assist Hams who were not as computer proficient got others on the mode in the true Amateur Radio Elmer tradition. To solve the third issue, most Hams went one of two routes: adding a rig interface accessory or using radios with built-in sound card interfaces. The two major rig interfaces available are the Tigertronics SignaLink™ USB Digital Communications Interface and MFJ 1204 Series USB Digital Mode Interfaces. They allow plug-and-play interfacing for most modern radios.

Although you can operate FT8 with older transceivers, the best experience will come by using a transceiver capable of both computer control and dedicated data mode. Fortunately, most modern radios have both of these. The extra feature that many of today’s radios have is a built-in sound card which eliminates the need for the external sound card interface. Many reasonably priced popular radios have this feature, including the ICOM IC-7300, Yaesu FT-991A, and Kenwood TS-590SG. If you are looking for a mobile/base radio, the ICOM IC-7100 HF/VHF/UHF also has these features and at a bargain price.

The release of FT8 reduced the time of a typical QSO by half, opening the floodgates as more and more Hams tried out this mode. The results: More Hams on the mode mean the more chances for QSOs, and the increased chance of a QSO—especially with rare DX stations— means the greater the number of Hams who want to get on the mode. Consequently, there is more demand to include the mode in contests. FT4 has been developed to allow better integration with exchanges used in contesting. It is also faster, again cutting QSO time in half.

One interesting fact confirmed by my own experience is that FT8 and FT4 are not just becoming a bigger part of Hams’ yearly QSOs—they are also increasing dramatically the activity on the post-WARC bands (60, 30, 17, and 12 meters). Activity is increasing in both sheer numbers as well as interest in WAS (Work All States) and DXCC on these bands. The second interesting fact, especially during this low sunspot period, is that we are seeing that bands we assumed were dead are actually supporting almost daily QSOs (see “Want to Work 6, 10 or 12 Meters But No Sunspots? Use Summer E Skip and FT8!”).

As for future trends, I think there will be more use of FT4 and a big increase in use of FT4 in contesting. One major move in this direction occurred during the last week of August with the first running of the WW Digi Contest. If this contest continues to grow, it may eventually rival the corresponding WW RTTY, WW Phone and WW CW contests.

*Along with being an Amateur Radio pioneer, astrophysicist and professor Joe Taylor, K1JT, won the Nobel Prize in Physics in 1993—one of many honors he has received during his illustrious career. Read more about his groundbreaking Weak Signal Communications Software at his official site.


[1]  Joe Taylor, K1JT (September–October 2005). “The JT65 Communications Protocol” (PDF). QEX: A Forum for Communications Experimenters: 3–12.

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