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 usage 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
ragchew
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 500/8, 500/16, 250/8, 1000/32, 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 HF activity is one of the 7 following
configurations : 1000/32, 1000/16, 500/16, 500/8, 250/8, 250/4,
and 125/4.
