Digital Modes Meanderings
Digital Modes Exploration – Olivia and Contestia
Popular OLIVIA modes
I have heard a few hams say that any mode that is wider than PSK63 (125 Hz bandwidth, that is not a typo) is “too wide of bandwidth and uses too much band space”. This view is complete nonsense. RTTY is 270 Hz wide when being run in its typical mode configuration of 45.45 baud and 170 Hz shift. Does anyone say that RTTY is “too wide”? No, so why say it about any digital mode running a similar bandwidth? This “using too much band space” argument is ridicules. There is plenty of band space available on all the traditional HF bands (160, 80, 40, 20, 15, and 10 meters). Of course, one should be considerate of others and not run wide bandwidth modes, for example, in the middle of PSK31 territory (e.g. 14.071 MHz). The argument should be “do not use wide bandwidth modes in an inappropriate place on the band”. The digital mode bands are not crowded wall to wall with signals every night. Even if they were, hams need to learn to move around. We are not bound by fixed frequency crystals. We have VFOs (variable frequency oscillators), so use them! Get familiar with and use that main tuning knob. I have heard this argument used for several modes, one being Olivia, which is sometimes run with very wide bandwidths (up to 1000 Hz wide). But even at 1000Hz bandwidth, that is only 1/3 the width of a SSB signal. Three 1000 Hz wide Olivia mode stations can operate where one SSB station operates. Does that make SSB “too wide” of a mode? The answer would be “yes” if you used it down in the CW section of the band! So mode bandwidth and band usage go hand in hand along with common sense (which is nowhere near common enough, IMO).
Because of its immense popularity, some consider PSK the King of the digital soundcard modes. If PSK is the King of the digital soundcard modes then Olivia is surely the Queen of the digital soundcard modes. While MFSK16 was an exponential increase in copy error reduction over PSK, Olivia went miles above and beyond that bench mark. Not only is it extremely remarkable in its ability to decode nearly error free, it does it in the most horrible of band conditions. QSB, QRN, QRM, doesn’t matter; Olivia gets through it all with near solid copy perfection. Now, there are always limits to anything and Olivia is no exception. As good as it is there still has to be some propagation to support the RF transmission. Olivia will continually amaze you as to how much and how well you can copy with poor band conditions. It is not unheard of to copy Olivia signals that are undiscernible to the eye or ear! These are the legendary “ghost QSOs”. I have experienced this phenomenon myself and it is very eerie the first time you encounter it. I was calling CQ on 30 meters using 16/500 (16 tones and 500 Hz bandwidth) mode Olivia. After a couple of CQ cycles I found myself staring at the receive screen. I suddenly realized that amid the random noise garbage copy my call sign was slowly and methodically being printed on the screen followed by another call sign with the prefix OZ (Denmark)! There was almost no evidence of a waterfall trace and no audible tones coming from the speaker. I was completely dumbfounded. After recovering from the initial shock, a complete series of QSO exchanges ensued and the “ghost QSO” was in the logbook. My admiration for the abilities of Olivia was forever sealed by the experience. My new favorite digital mode was here.
It has been said that there is always a price to pay for anything. Olivia does have one drawback for a few digital operators (not me!). The penalty (if you choose to call it that) for Olivia’s fantastic copying abilities is speed, or lack thereof, for most of the better decode mode selections (e.g. 8/250, 16/500). It is a mode that uses error correction techniques and it takes time to send and receive the transmitted message. I don’t think of it as being all that slow but compared to PSK it definitely is slower and some folks just can’t make the transition very well. But as I have told many hams in my Olivia QSOs, “I would rather send it slow once than fast multiple times”. There is a saving grace for Olivia in respect to the speed issue. Since it supports 40 (!) different mode configurations, there is always a combination that balances good copy verses speed. There is one that will suit you too! However, you better use some form of mode identification if you use an “exotic” seldom used Olivia mode. It can be hard enough to find contacts at times even with the more commonly used mode configurations. I will cover mode identification methods later.
Because of its immense popularity, some consider PSK the King of the digital soundcard modes. If PSK is the King of the digital soundcard modes then Olivia is surely the Queen of the digital soundcard modes. While MFSK16 was an exponential increase in copy error reduction over PSK, Olivia went miles above and beyond that bench mark. Not only is it extremely remarkable in its ability to decode nearly error free, it does it in the most horrible of band conditions. QSB, QRN, QRM, doesn’t matter; Olivia gets through it all with near solid copy perfection. Now, there are always limits to anything and Olivia is no exception. As good as it is there still has to be some propagation to support the RF transmission. Olivia will continually amaze you as to how much and how well you can copy with poor band conditions. It is not unheard of to copy Olivia signals that are undiscernible to the eye or ear! These are the legendary “ghost QSOs”. I have experienced this phenomenon myself and it is very eerie the first time you encounter it. I was calling CQ on 30 meters using 16/500 (16 tones and 500 Hz bandwidth) mode Olivia. After a couple of CQ cycles I found myself staring at the receive screen. I suddenly realized that amid the random noise garbage copy my call sign was slowly and methodically being printed on the screen followed by another call sign with the prefix OZ (Denmark)! There was almost no evidence of a waterfall trace and no audible tones coming from the speaker. I was completely dumbfounded. After recovering from the initial shock, a complete series of QSO exchanges ensued and the “ghost QSO” was in the logbook. My admiration for the abilities of Olivia was forever sealed by the experience. My new favorite digital mode was here.
It has been said that there is always a price to pay for anything. Olivia does have one drawback for a few digital operators (not me!). The penalty (if you choose to call it that) for Olivia’s fantastic copying abilities is speed, or lack thereof, for most of the better decode mode selections (e.g. 8/250, 16/500). It is a mode that uses error correction techniques and it takes time to send and receive the transmitted message. I don’t think of it as being all that slow but compared to PSK it definitely is slower and some folks just can’t make the transition very well. But as I have told many hams in my Olivia QSOs, “I would rather send it slow once than fast multiple times”. There is a saving grace for Olivia in respect to the speed issue. Since it supports 40 (!) different mode configurations, there is always a combination that balances good copy verses speed. There is one that will suit you too! However, you better use some form of mode identification if you use an “exotic” seldom used Olivia mode. It can be hard enough to find contacts at times even with the more commonly used mode configurations. I will cover mode identification methods later.
Which is OLIVIA and which is CONTESTIA?
In response to the slow speed issue, the Olivia variant called Contestia was created. It is a bit faster by limiting the character set that can be sent. It only sends in upper case letters. Contestia is slightly faster but also is slightly less robust in its poor band conditions copying ability. Not a lot of difference, but it is noticeable to the veteran Olivia mode operator. So if the speed is an issue for you then Contestia is an option. Be forewarned, Contestia looks and sounds exactly like Olivia. It can be difficult for even seasoned digital operators to identify the mode you are running (Olivia or Contestia) unless you utilize some form of mode identification. So if someone calls on your frequency and you cannot decode their transmission, he may be guessing (incorrectly) what mode you are using. So without usage of a mode identifying method, odds are both you and the other digital operator will be muttering unflattering things about each other!