Re: LF: 500 opera V

[Markus Vester <markusvester@aol.com>]

Eddie,

 

my guess is that in the "Opera vs QRSS" challenge, Mal's odds wouldn't be bad at all:

 

Graham stated that Opera-8 should decode above SNR -32 dB in 2.5 kHz (average). Referenced to 1 Hz, this is +2 dBHz average, or about + 5 dBHz for the CW carrier.

 

QRSS-10 could transmit a callsign approximately in the same amout of time. It is received eg. in Argo at 0.084 Hz FFT bandwidth, equivalent to 0.13 Hz or -9 dBHz noise bandwidth. Thus the marginal Opera signal would be a very comfortable 14 dB SNR in QRSS. 

 

We typically give "O" reports on QRSS signals above 10 dB SNR. This would mean that QRSS could be twice as fast as Opera...

 

Some may prefer the digital decoder from the visual one because "100% all-or-nothing". In my opinion this is not a benefit, as there is no way to detect a signal below the threshold, and judge how much was missing or what type of QRM was present. Of course, with a digital mode yu don't have to bother investigating spectrograms - well, borrowing a term once coined by G3KEV, then that's the ultimate "lazy man's CW" ;-)

 

Best 73,

Markus (DF6NM)

 

-----Ursprüngliche Mitteilung-----
Von: Graham <g8fzk@g8fzk.fsnet.co.uk>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Fr, 6 Jan 2012 9:50 pm
Betreff: Re: LF: Opera questions

...

OP31 expected  round  -38 dB  s/n  (ave)     OP8   ~  -32 dB 

 

G..

-----Ursprüngliche Mitteilung-----
Von: qrss <qrss@talktalk.net>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: So, 29 Jan 2012 9:25 pm
Betreff: Re: LF: 500 opera V

So Mal

Can you see or hear my 12WPM Morse ident between my OPERA signals? I doubt it. I could put QRS3 between, that would be a good test. Say a cryptic message for decipher, one transmission and that is it, if Opera decodes and the QRS remains unread OPERA wins.

Eddie

On 29/01/2012 19:53, Graham wrote:

R Mal

Those  signals where  about  10 db over the  limit ,  so  will  show , OP16 ,  is about 6  dB lower  again. but  a decode  is a decode.. good  start.  

14:44 500 G3ZJO de G3KEV Op4 142 miles -22 dB in SCARBOROUGH

136  is  being  most  used  at the  moment   RA9CUA  is  monitoring 

Show all seen by RA9CUA
Last report: RN3AGC

G..

From: mal hamilton

Sent: Sunday, January 29, 2012 6:14 PM

To: rsgb

Subject: LF: 500 opera V

MF

On 500 Khz so far signals decoded in Opera mode have been visible on the waterfall therefore had the mode been QRSS the result would have probably been better and quicker in QRS 3 - 10

The mode is however interesting and needs little operator intervention.

de mal/g3kev