Hugh ,
By 'time' I was more concerned with the synchronisation , along the
time line , ' clock jitter ' in computer speak .. if sections of the
time line are displaced due to IRQ action or similar , you could reduce
the system's ability to reach maximum - s/n
Opera requires ~ min of 40% capture of the Tx signal , along the time
line , either randomly , blocks or 40/60 split , using manchester coding ,
each data 'bit' is self-sync , so it impossible to 'loose' lock.. where
as a conventional system would need to establish sync at the start ,......
as long as 40% of the opera recovered [or sent !] plays ball , it will
decode , [ or detect for dynamic, has the same 40% requirement]
or in wspr case , sync is provided externally If the time line is then
jumped , the system will no be able to recover the data , and as in
the 2 pass wspr , unless the two signals are exactly the same in
time and coherent phase , the expected +3 dB gain cannot be realised .
73-G,
--------------------------------------------------
From: "LineOne" <[email protected]>
Sent: Saturday, October 22, 2016 11:20 AM
To: <[email protected]>
Subject: Re: LF: Simultaneous decoding of WSPR on LF
I checked the PC time and it seems that the Realtek software stops "net
time" from loading on occasions so, for another reason as well, I
eventually found some older Realtek software that doesn't do this. The
software supplied with the motherboard will not share the "line out" with
any software if it's used for, as I do, a small speaker amplifier. It has
to have the Realtek drivers loaded otherwise no audio at all.
73, Hugh
On 21/10/2016 23:27, Graham wrote:
May be down to time Hugh ,
Opera is free running, so absolute time reference has no effect on the
system performance ..
Stephan should have the solution, his night garden uses similar
things .
The other is cpu loading ?
73-G,
--------------------------------------------------
From: "LineOne" <[email protected]>
Sent: Friday, October 21, 2016 11:10 PM
To: <[email protected]>
Subject: LF: Simultaneous decoding of WSPR on LF
So far I've been decoding Opera32, WSPR2 and WSPR15 simultaneously on an
old IBM "Thinkpad" in the shack. This weekend I've managed a wireless
connection to a desktop PC in the house so only a receiver is running in
the shack leaving nice, clean signals.
Decoding Opera 32 is going well (3000km best so far this evening) but
the PC, with the same operating system and radio software, will not
decode any WSPR at the same time. I haven't yet tried running just
WSPR-X (for WSPR2) on it's own but it does show a good signal on the
waterfall if I arrange a 1.5kHz heterodyne in the shack. Why would a
supposedly superior computer refuse to cooperate, I suspect the Realtek
on-board sound card and software is not actually up to the job?
73, Hugh, M0DSZ
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