Lesser Known Digital Modes Part 1: Olivia

With the popular WSJT FT8 digital mode absolutely taking over the high frequency bands, some among us have been left looking for a return to something with little more… personality.

There’s something to be said about digital modes that offer the next generation of amateur radio operators a classic take on modern text-based communication. This series of blog posts is designed to showcase some of the interesting, but lesser known digital modes available.

Olivia: The Magical Mode

Olivia was first developed in 2003 by Paweł Jałocha with the intent to improve upon weak signal communications. It is a high duty cycle transmission mode which enhances the popular multi-shift frequency keying (MFSK) technique, providing an additional layer of forward error correction. It is this additional layer of error correction that allows Olivia to be a high signal-to-noise ratio champion.

The modulation layer of the Olivia transmission system in the default mode sends one of 32 tones at a time. Each tone thus constitutes a symbol that carries 5 bits of information. For the FEC code, 64 symbols are taken to form a block. Within each block one bit out of every symbol is taken and it forms a 64-bit vector coded as a Walsh function. Every 64-bit vector represents a 7-bit ASCII character, thus each block represents 5 ASCII characters.

This way, if one symbol (tone) becomes corrupted by the noise, only one bit of every 64-bit vector becomes corrupt, thus the transmission errors are spread uniformly across the characters within a block.

This all adds up to a mode that is capable of clear and readable ASCII text, while using weak signal transmissions up to 10-15 decibels below the noise floor. Not unlike the popular FT8 mode, Olivia shines in the worst of band conditions, enabling a rag chew style conversation.

A Word About Bandwidth

There are 40 Olivia bandwidth and tone combinations available. Each offers more or less bandwidth occupation in the spectrum, leading to faster or slower transmissions, depending on the bandwidth and number of tones. The most commonly used formats are 500/8, 500/16, 250/8, 1000/32, and 1000/16. You’ll find that the popular software offerings for this mode will allow users to easily switch between formats when desired, even mid-QSO.

Where Can I Find It?

Olivia signals can frequently be decoded by software even when the signal is so weak that it barely registers on a waterfall spectrum display. This means decoding is often possible even when you can’t hear the signals. As a result of this, the Olivia community has undergone voluntary channelization of communications. This means that Olivia can be found on very specific frequencies in each band; operators can easily find each other and relocate to another frequency.

Get Involved

Olivia can be found in all major digital HF software offerings including the commercial Ham Radio Deluxe and open source FLDigi. It’s as simple as running the software, connecting it to your transceiver, and calling CQ on one of the standard Olivia frequencies.

The Verdict

I recently experienced my first QSO in the Olivia mode for the first time and it was a lot of fun. Operating my Elecraft KX2 at 10 watts with an (indoor!) magnetic loop antenna, I sought out to make contact on the 40 meter band. Antenna pointed north / south I called CQ. Immediately after calling it once, I received a reply from Dan (VE9DAN) approximately 450 miles to the northeast of my station. Not bad considering how terrible the band conditions were and the nature of my compromised indoor antenna. I was able to clearly communicate with Dan (thanks to his patience) and had a nice chat. All in all, it was a great QSO and I will definitely be exploring this mode more.

If you’re looking for an easy to use, high noise tolerance digital mode, take a look at Olivia. Please let me know of your experiences with the Olivia mode in the comment section below.

References

Experimental 20-meter Raspberry Pi WSPR Beacon

If you’ve read my last post, you’ll be familiar with the WSPR digital mode and how incredibly impressive it can be even in the most awful band conditions. I’ve decided to start a long term project with this mode, centered around the Raspberry Pi mini computer.

Modernizing the Beacon Concept

Through the General Class licensing process, I learned about the traditional Morse code-based propagation beacons that are present on HF bands. Given my background in software and Linux-based platforms, the idea of a modern, WSPR-based digital beacon is attractive. The idea was that if I couple that knowledge with the reporting / mapping system behind WSPRnet, I could probably discover some very interesting long term trends regarding 20-meter propagation from my transmitter.

I dug around and found the WsspryPi GitHub page. The discovery that a stock RPi could be used as a 100mW transmitter with the addition of a simple low pass filter helped put the plan into action.

Raspberry Pi Shield

Not being terribly well versed in soldering (I’m working on it.), or building electronics in general I sought out an off the shelf solution. I discovered the excellent TAPR 20m WSPR-Pi TX shield and less than a week later, the beacon is up and running.

For the near term, it’s just using some basic 18 gauge stranded copper wire, cut to length for the 20-meter band, inside the house. I’m running the beacon periodically whenever I have the opportunity to turn it on and activate the program. The map screenshot at the top of this article is a collection of reports from some day-long testing of the beacon.

Long Term Plans

Long term, I plan to extract the reports of my individual call-sign beacon receptions on WSPRnet and add them to a custom database. From there, the possibilities are extensive including reporting, mapping, long term projections and statistics outside of the WSPRnet platform.

How You Can Help

Spot that beacon! If you’re receiving 20-meter WSPR, make sure you’re automatically reporting to WSPRnet and the system can do the rest. I’d love to hear your feedback, whether it be on this site, Twitter, or QRZ. Let me know what you think.

WSPR the Bands Back to Life

Since becoming licensed, I have spent some time evaluating the general state of HF band propagation conditions in mid-2017 through both pure scientific data and Twitter / Reddit anecdotes. Needless to say, the general consensus is grim!

The bands are dead.

That might be the most common quote I have read online. I have not had the luxury of transmitting during the peak of the solar cycle, so I have little to compare the current conditions to. None the less, I’m having a blast. I see weak band conditions as an opportunity to do the impossible – to chase the furthest DX with the absolute weakest power in the worst of conditions. I’m not sure what that says about my personality.

WSPR to The Rescue

I’ve discovered WSPR and have had a lot of fun with it. It’s pretty much completely hands off and fully automated, the type of thing I can do while multitasking. That’s right up my alley.

The featured image at the top of this post was achieved in a 20 minute period on the 20 meter band (14.095.60 to be specific) at 100 milliwatts with a piece of copper wire I hung up on the inside of the house on a window shade.

Sure, it’s no big time DX SSB phone contact, but in these times of dead bands I’m having a blast on weak signal digital modes. Get out there and WSPR!

Greetings!

Welcome to KD2NSP.com. This website explores my free time research into the radio frequency spectrum.

I’m a newly licensed amateur radio operator with a wide variety of interests including HF digital modes, QRP, APRS, CW and more.

Expect to see posts on an irregular basis covering my latest topics of interest. Thanks for checking it out!