Different flavors of Olivia

It would appear that most nets have standardized on Olivia 8-500, which has a decent tradeoff in terms of speed vs. reliability.

However, Olivia is not limited strictly to 8-500 (which stands for 8 carrier/500 Hz).

Was having problems copying a station last night on our net on 80m.  I was able to switch from Olivia 8-500 to Olivia 8-250.  That reduced the required s/n from -11 dB to -14 dB.  Suddenly we went from 35-50% copy to 100% copy, as the other station's signal was fluctuating between -9 and -12 dB.  Of course, we also took a 50% cut in data throughput when we reduced the bandwidth from 500 Hz to 250 Hz.  However, 100% copy at 50% speed beats 35% copy at full speed any time!

Here is a sort summary of how the different types of Olivia compare (courtesy of the W1HKJ web site for FLDIGI):

Mode	Baud	WPM	Duty Cycle	BW (Hz)	Modulation	S/N	ITU	RSID-1	RSID-2
OLIVIA-4-250	63	20	100.00%	250	4-FSK	-12 dB	250HF1B	75
OLIVIA-8-250	31	15	100.00%	250	8-FSK	-14 dB	250HF1B	69
OLIVIA-4-500	125	40	100.00%	500	4-FSK	-10 dB	500HF1B	74
OLIVIA-8-500	63	30	100.00%	500	8-FSK	-11 dB	500HF1B	72
OLIVIA-16-500	31	20	100.00%	500	16-FSK	-13 dB	500HF1B	70
OLIVIA-8-1000	125	58	100.00%	1000	8-FSK	- 7 dB	1K00F1B	116
OLIVIA-16-1000	63	40	100.00%	1000	16-FSK	-10 dB	1K00F1B	73
OLIVIA-32-1000	31	24	100.00%	1000	32-FSK	-12 dB	1K00F1B	71