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Message-ID: <65043EEC8A5C4D34B73EA8F5EA9A1771@JimPC>
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
References: <4F1BE531.7370.A577295@mike.dennison.ntlworld.com>
In-Reply-To: <4F1BE531.7370.A577295@mike.dennison.ntlworld.com>
Date: Sun, 22 Jan 2012 12:58:31 -0000
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Subject: LF: Re: Opera - initial thoughts
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Dear Mike, LF Group,
>
> Is it better than QRSS?

It *is* QRSS8 (in Op32 mode), only instead of morse code, it uses an 
error-correcting code of some sort, details closely guarded by Mr. Ros.

> However, I have not yet seen any evidence that it can beat QRSS at
> the most marginal level.

Op32 sends a callsign in 32 minutes, which for throughput is about the same 
as QRSS30 or DFCW60. I guess under marginal conditions, it is very roughly 
comparable with those modes. The difference is that Opera gives you a 
"binary" result - either perfect copy / positive ID, or nothing at all, 
while QRSS gives you a result varying from "traces of signal" through "some 
bits missing but very likely your signal" to "solid O copy". So a marginal 
QRSS beacon signal might give you at least a partial result under conditions 
where Opera yields nothing but a blank screen, and you can usually increase 
the confidence of station identification from other information, such as 
knowing who is active, what frequency is being used, etc. On the other hand, 
if the Opera screen shows "G3XDV" once, you can be practically certain you 
have received G3XDV even if you have no other knowledge of 136k operations, 
and you don't have to spend any time trying to interpret the results.

If Opera evolves into a QSO mode, I guess Op32 would be the slowest 
practical format to use; it would allow a "rubber stamp" QSO with callsigns, 
reports and confirmation exchanged within a few hours - much longer than 
that would be rather impractical. The faster formats would certainly be 
feasible where the shorter-duration QRSS modes are currently used. For DX 
beacon use on 136k, Op32 isn't quite enough, and there is no great pressure 
on time - I definitely think there is a case for trying Op64, Op128...

I think nice features of Opera are:
-Easy and non-critical to set up and use
-Can be used with a simple CW TX
-"Slow" Op32 option better suited to 136k DX than other comparable modes, 
e.g. WSPR
-Automated reception with web-based reporting
-Simultaneous multi-mode reception

I think the current down-sides are:
-The "black box" nature of the package - not knowing what it is you are 
using,  what it is doing (especially via the internet), having few control 
options
-Seems to put a lot of load on the CPU
-When I download the latest version, I don't want to go on a date ;-)

Cheers, Jim Moritz
73 de M0BMU