Technical Articles

Ham Radio Digital Modes: There’s Something About Olivia

FT8 has taken over ham radio by storm in recent years, especially in the digital mode category. Just look at any spotting site, like DX Summit, and you’ll see an abundance of ops using FT8. It allows for quick exchanges and the ability to make contacts even in difficult propagation conditions.

But FT8 lacks the personal touch, like a quick handshake with no personality. Some argue that FT8 doesn’t allow for much human interaction. The computer is doing it all—QSOs are mostly automated, and racking up contacts is easy. As Ron Popeil used to say in his rotisserie commercials, “Set it and forget it.”

In the ham world, where rag chewing is slowly becoming an endangered art, many ops still look forward to chatting with other amateurs. If you are interested in more than a logbook QSO and want to converse with other hams around the world using digital modes, consider Olivia as one option.

Meet Olivia

Twenty-year-old Olivia is similar to RTTY. It uses multiple frequency-shift keying (MFSK) and is designed to work in difficult conditions on the HF bands. The signal can be accurately received even if the surrounding noise is 10 dB stronger. Olivia is commonly used by amateur radio operators to reliably transmit ASCII characters over noisy channels.

The first on-the-air tests were performed by two radio amateurs, Fred, OH/DK4ZC and Les, VK2DSG, on the Europe-Australia propagation path in the 20-meter amateur band. The tests proved that Olivia works well and can allow regular intercontinental radio contacts with as little as one-watt RF power when propagation is favorable.

Olivia decodes well under conditions that are a complex mix of atmospheric noise, signal fading (QSB), interference (QRM), and polar path flutter. Olivia is even useable when the signal is affected by auroral conditions, including the sporadic-E auroral mode.

Modes are commonly referred to as Olivia X/Y (or, alternatively, Olivia Y/X), where X refers to the number of different audio tones transmitted and Y refers to the bandwidth in Hertz over which these signals are spread. Examples of common Olivia modes are 16/500, 32/1000, and 8/250. Olivia’s transmission system is constructed of two layers. The lower modulation layer is MFSK and the higher layer is a Forward Error-Correcting (FEC) code.

Olivia on the Air

Currently, the only other digital modes that meet or beat Olivia in sensitivity are some of the modes designed by Joe Taylor as implemented in the WSJT programs, including FT8, JT65A, and JT65-HF, which aren’t able to provide true conversation capabilities. Unlike JT65A or FT8, Olivia is useful for emergency communications.

While it can decode weak signals, it’s not a weak-signal mode like JT65 or FT8. The Olivia mode was not primarily designed for weak-signal decoding but to overcome propagation-path phase issues and transpolar-region propagation issues on HF.

Given the many digital modes out there, it can be difficult to figure out which mode you are seeing and hearing. After getting used to the sound and look of Olivia in the waterfall, it becomes easier to identify the format. To help detect which mode is being used, many digital-mode software implementation suites have RSID (Reed-Solomon Identification). In Fldigi, RSID is identified as TXID and RXID. Be sure to activate this feature—it will help you make more contacts.

Since Olivia signals can be decoded even when received signals are extremely weak (signal-to-noise ratio of −14 dB), signals strong enough to be decoded are sometimes below the noise floor. As a result, amateur operators have voluntarily adopted channelization for this mode. This channelization allows even extremely weak signals to be properly tuned for reception and decoding.

Stations start contacts utilizing either the 16/500 or 32/1000 modes, then switch to other modes to continue the conversation. Table 1 lists the common center frequencies used in the amateur radio bands. It’s based on community collaboration after the introduction of new digital modes and the overlapping of Olivia calling frequencies on some amateur bands. Table 2 lists common Olivia modes, speed, and bandwidth.

When you call CQ, be patient and wait at least 45 to 60 seconds before you put out another call. When the other person who hears your CQ clicks on the waterfall, it may take four to 20 seconds (or even longer) before they might actually start decoding your signal. That varies a lot depending on the software they are using and Sync Integration Period settings.


In response to Olivia’s slower speed, a variant called Contestia was created by Nick Fedoseev, UT2UZ, in 2005. It’s a bit faster because it limits the character set by sending only in uppercase letters. Contestia is slightly less robust in its copying ability in marginal conditions. But if speed is important to you, it is an option.

Contestia is twice as fast as Olivia in each of its configurations, providing excellent weak-signal performance, rag chewing, and QRP and DX digital mode operation. When rag chewing under fair or better conditions it can be more useful to many hams than Olivia because of the faster speed. For contests it might also be a good mode if faster configurations such as 1000/8 or 500/4 are used.

Contestia looks and sounds just like Olivia. It can be difficult for even seasoned digital operators to identify which you are running unless you use some form of mode identification like RSID. Avoid the frustration of guessing what mode is in play.

More Choices

I’ve heard some statistics that claim more than half of all contacts on HF are now made using FT8. Though many are engaged in hello-goodbye digital QSOs, it’s also true that some of us still want to do more than exchange call sign, grid location, and signal strength wrapped up with a 73.

Digital program developers realize this and are building new keyboard-to-keyboard modes based on existing ones. One example is JS8Call, a derivative of WSJT-X (the FT8 family), adding chat and directed message capabilities. It’s a digital mode with the robustness of FT8, combined with a messaging and network protocol layer for weak-signal communication on HF.

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