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Message-ID: <7C234838C15E4E18A6A7374FA2C5C592@JimPC>
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
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Date: Sat, 3 Jan 2009 01:36:17 -0000
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Subject: LF: Re: Olivia QSO
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Dear Graham, LF Group,

Thanks for our first QSO this evening. As keyboard-to-keyboard "chat" modes 
go, this has to be the best I have experienced so far at LF/MF. The 32 
tone/1kHz sub-mode produced almost 100% copy provided the signal was 
audible - the somewhat slower 4 tone/250Hz setting was better still, only 
producing errors during short periods at the fading minima when the signal 
was completely inaudible and invisible on the spectrogram as well. I have 
always struggled to copy G0NDB before, but on this occasion we had a fairly 
lengthy QSO without any great difficulty. I think the main practical 
difficulty for random QSOs would be knowing that there was a signal present 
to decode - it would be sensible to have a calling frequency for future 
tests.

I would agree that the 1kHz bandwidth sub-mode is too wide for routine use 
in the present 500kHz band. But it does not violate the present licence 
conditions, and I think it is an interesting experiment to see if a 
relatively wide-band mode is an advantage for selective fading conditions on 
this band. Looking at the various menus in Fldigi, I see that Olivia can be 
configured for any combination of bandwidth from 125Hz to 2kHz, and 2 - 256 
tones (I tried it - you can have 256 tones and 125Hz, or 2 tones in 2kHz, 
although how well it works is another matter...). It would be interesting to 
try back-to-back comparisons with varying parameters to test the 
possibilities of fast vs. slow, wide vs. narrow.

Cheers, Jim moritz
73 de M0BMU