May 25th 2008
Mode to try: Olivia

Description
===========

Olivia (invented by Pawel Jalocha SP9VRC and named after his daughter)
is an MFSK mode with a very strong FEC (Forward Error Correcting) code
based on Walsh functions.

In use it can provide very reliable copy even on very weak signals.
Many times you may not even see the trace in the waterfall but you still
get 100% copy.

The only trade-off for this is the overall speed which tends to be slower
than PSK31 and a wider bandwidth.


Specifications
==============

MultiPSK's help pages say this about Olivia....

Speed:           See below for specific examples
Modulation:      MFSK 32 tones (5 bits arranged in a Gray form)
Sideband:        USB recommended
Character set:   ASCII 7 bits (128 characters)
Interleaving:    Spreading of 5 bits "vertically" in the "block"
Scrambling:      yes, with a 64 bits sequence applied on each line
                 of the block but with a delay of 13 bits between
                 two successive lines.
Drift tolerance: 30 Hz/mn according to signal-to-noise ratio,
Pmean/Ppeak:     0.76
Lowest S/N:      See below

There are many bandwidth & tone combinations for this mode with the
most common ones being:-

1000Hz / 32 tones
speed=31.25 bauds, 24.4 wpm, lowest S/N =-13 dB

500Hz / 16 tones
speed=31.25 bauds, 19.5 wpm, lowest S/N =-13 dB

500Hz / 8 tones
speed=62.5 bauds, 29.3 wpm, lowest S/N =-11 dB

250Hz / 8 tones
speed=31.25 bauds, 14.6 wpm, lowest S/N=-14 dB

250Hz / 4 tones
speed=62,5 bauds, 19,5 wpm, lowest S/N =-12 dB


Operating guide
===============

In use Olivia is quite easy to tune. At the start of transmission there
are two brief carriers sent which indicate the left and right "edges" of
transmission. From this it is quite easy to guess the bandwidth used.

On 30m, you will usually only hear the 500Hz & 250Hz modes because of the
narrow data segment. Most of the time 500Hz/16 is used but when signals
are weak you will often hear people switching to 250Hz/8.

Regarding operating practice it is the same as using MFSK-16. Just make sure
your intended transmission is of the correct bandwidth and not likely to
transmit over the top of other stations.

Be aware that there can be very weak stations on frequency who are
already in QSO.

If you use MultiPSK or PocketDigi then use of the RS ID header and detection
can help you find these weaker signals.

There are several other modes which are similar (and sound similar) to Olivia,
notably Contestia and RTTYM however these are rarely used.

MultiPSK has a mode called "VOICE" which is directly based on Olivia and has 
only a 168Hz bandwidth using 8 tones. It's sensitivity should be very similar 
or better than the 250Hz Olivia modes and similar WPM.

The name "VOICE" comes from the fact that there is an option in the mode to
repeat every character received by a speech synthesizer, the idea being that
partially sighted amateurs might find this useful.

There is no need to enable the voice synthesizer however so you can treat it 
just like a normal Olivia QSO.

Because of the narrow data segment on 30m I think the "VOICE" mode is also 
worth a try this Sunday.


Recommended Frequencies
=======================

Most activity on 30m is around 10.134MHz to 10.138MHz USB dial
frequency. I suggest that this Last Sunday event also follow
these common frequencies. That will still leave room for the PSK31
folks, however if you are careful to avoid QRM then transmitting
above 10.141MHz may also yield QSOs.

Availability
============

Just about every multi-mode program out there has
Olivia.

Some recommended Windows software to try:

MultiPSK    http://f6cte.free.fr/
MixW        http://www.mixw.net/
DM780       http://hrd.ham-radio.ch/DM780/DM780.htm

And for Linux, you could try

FLDigi      http://www.w1hkj.com/Fldigi.html

Spotting is encouraged and you can use the spot page at 
http://www.projectsandparts.com/30m/


Sound Sample
============

Click here to listen to an Olivia 500Hz/16 tone signal (mp3 format)
Click here to listen to an Olivia 250Hz/8 tone signal (mp3 format)

Links
=====

Pawel's original webpage detailing Olivia is here:
http://homepage.sunrise.ch/mysunrise/jalocha/mfsk.html

73 es GL!
Sholto, KE7HPV
Republic, WA.

Comments or errata to: KE7HPV