Olivia is a ham radio digital mode designed to work in
difficult (low s/n ratios plus multipath propagation) conditions on HF
bands (though it also works as well on VHF/UHF). The signal can be
decoded even when it is 10-14 db below the noise floor (i.e. when the
amplitude of the noise is slightly over 3 times that of the signal).
It can also decode well under other noise, QSB, QRM, flutter (polar
path) and auroral conditions. Currently the only other digital
modes that
match or exceed Olivia in sensitivity are some of the WSJT program
modes that include JT65A which are certainly limited in usuage and
definitely NOT ragchew capable.
It was developed at the end of 2003 by Pawel Jalocha. The
first on-the-air tests were performed by two radio amateurs, Fred
OH/DK4ZC and Les VK2DSG on the Europe-Australia path in the 20-meter
amateur band. The tests proved that the protocol works well and can
allow regular intercontinental radio contacts at very low power levels.
It therefore lends itself to be an excellent QRP and rachew mode.
Olivia has many formats some of which are considered
standard and they all have different characteristics. The
formats vary in bandwidth (125,250,500,1000, and 2000hz) and number of tones
used (2,4,8,16,32,64,128, or 256). This makes it possible to have 40
different Olivia formats which have different characteristics, speeds,
and capabilities. Luckily only a relatively few are commonly used.
The standard Olivia formats
(bandwidth/tones) are 125/4,
250/8, 500/16, 1000/32, and 2000/64. However the most commonly
used formats in order of use are 500/16, 500/8, 1000/32, 250/8,
and 1000/16. This can cause some confusion and problems with so many
formats and so many other digital modes. After getting used to the
sound and look of Olivia in the waterfall, though, it becomes easier to
identify the format when you encounter it. About 98% of all
current Olivia activity on the air is one of the 7 following
configurations : 1000/32, 1000/16, 500/16, 500/8, 250/8, 250/4, and
125/4.
