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Yes , Marco
The user interface is indeed simple ,
and the equipment/system over heads are minimal ,
also can add, the system was designed to allow
access to data for the many CW
and QRSS transmitters on 136/500 ....
however the DSP engine is where the
real work is carried out , (under wraps of
course) , the low level of false decodes and
s/n levels , gives a insight to the
development in this area ,
No time locking
No sound card calibration
Lax frequency stability requirements
OOK or FSK may be used
The On/Off keying has benefits other than
allowing access via simple Tx systems , it
gives immunity to Doppler
spread and allows the averaging of the data
to be used for detection , whilst embodying
non-liner routines to eliminate static crash problems .
it not being possible to 'loose' lock , due to the
coding scheme . performance on vhf is also
significant and the system has been included in
the next generation of vhf smart beacons.
I think the difference between data
demodulation and carrier detection are often blurred ,
Markus correlation process is notable , with
a 10 dB gain, however , the Tx pattern is
detected / compared against 'known reference' ,
the same during the testing of the OP4 Hr ,
8k audio mode , at -50 dB was 10 dB
sort of the spec-lab detection level ,
but again that was a data / carrier comparison , 8K has yet
to be seriously air-tested , its quite
possible , Stefan will achieve considerable range , if
he transmits at the previous test levels ,
due to the long tx pulses , the Op4 Hr signal ,
also shows on spec-lab , so test data is not
lost if decode fails.
As to what is better , that remains to be
seen under operational conditions , Jose is quite
confident the OP on/off system is fit for
purpose and predicts a practical gain of only
-3 dB from a change to the modem
to mfsk or psk , ( theoretical levels are
-6 ) but these do not take realistic path
variations into account , exchanges have taken
place on this subject , a psk version could be
some -5/6 dB better , but then access by all
but very few MF/LF stations would be
possible ,
The benefits of the combined data processing
and modulation scheme can be demonstrated to
off set the dB losses
73 -G..
Sent: Saturday, September 22, 2012 8:38 PM
Subject: Re: LF: Re: Experimental software for WSPR-8 and
-32
hi,
"simple" =
- modulation ON-OFF , no needs for
linear P.A.
- no precise timing (= little beacons stand_alone. no PC.)
-
TX only 50% on. (to take in mind when compare whith other "continous" mode at
parity of output power.)
- the coding scheme is more robust than WSPR.
73 de Mauro IK1WVQ
At 17.36 22/09/12, you wrote:
Interesting
...
Define 'simple'
?
G..
From: IK1WVQ
Mauro
Sent: Saturday, September 22, 2012 4:21 PM
To:
[email protected]
Subject: Re: LF: Re: Experimental software for WSPR-8 and
-32
Hi to all,
only a question to the experts:
is the
SLOW WSPR better than the simple OPERA-32 ???
73 de Mauro
K1WVQ
At 16.57 22/09/12, you wrote:
Hi Markus, LF,
It works!
First reception of DF6NM in WSPR-8 here.
Timestamp Call MHz SNR Drift
Grid Pwr Reporter RGrid km az
2012-09-22 14:40
DF6NM 0.137538 0 0
JN59nj 0.5 DK7FC/8 JN49ik
175 272
2012-09-22 14:30
DK7FC 0.137499 +13 0
JN49ik 1 DK7FC/8 JN49ik
0 0
I have used a virtual audio cable, with
success.
For those who still try without success, here is my
description in simple words.
If your RX is a HF TRX at 136 kHz dial
setting, then the tone of DF6NM appears at 1440 Hz, the tone of DK7FC
appears at 1430 Hz.
The microphone input is used and it must be
defined as the standard audio input device. This is important since the
SounInput program related always to the default input.
Then
soundinput generates the audio file and replays it in
SoundOutput.
SoundOutput replays it to the standard audio output
device, which is the virtual audio cable 1 for me. So VAC1 must be defined
as the standard output device!
The sound input of the WSPR software
must be set to VAC1 too.
The file wspr-8_rx.bat must be edited. If
the BFO frequency in the WSPR software is 1500 Hz, then this value must be
inserted for fc in the row for the soundoutput settings.
Set the
value for fc for soundinput (the row below) to 1450 Hz and save the
file.
Then double click wspr-8_rx.bat and wait some minutes. You may
watch the small souninput and soundoutput windows...
Hope it works
for others as well now.
73, Stefan7DK7FC
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