OP4 had a number of misses
Which , if you take into account ,
Opera is single tone on/off
with app 50% duty cycle , self sync mode
and wspr is a 4 mfsk
externally time locked
For the test to be valid , the wspr
carrier level would of needed to be
50% less that of the Opera system
However as the 2 modes decoded at a
high % of times , with a 50% bias , then the
conclusion tends to the
inverse of the results ,
That is not making suitable allowances
for the spreading gain of 4 mfsk and
the external time synch , both of
which
reduce the payload on the transmission format , which
would tend to indicate a higher efficiency in the
design concept
of the Op mode in areas other than the modulation
If a normal 2 tone rtty is slowed
to the same baud rate as wspr-2 it
falls short by only 6 dB in terms of
sensitivity and that requires no external
time locking .
Bench testing and reality seldom agree , however
it helps if the tests are actually
correctly designed and fit for purpose
G,
Sent: Friday, September 27, 2013 4:13 PM
Subject: LF: Re: QRSS OP WSPR
Stefan
Test conditions:
Transmit end: single transmitter, single
antenna - signals combined in common TX setup
Receive end: single receive antenna, single
receiver, single computer/sound card - WSPR and OP running
simultaneously
Power at TX end adjusted to provide
weak signal at receive end. Standard weak signal receive setup was used ...
complete with QRN, QRM, other signals etc. Test began during daylight,
proceded through the night and ended in
daylight.
Jay W1VD WD2XNS WE2XGR/2
WG2XRS/2
----- Original Message -----
Sent: Friday, September 27, 2013 10:08
AM
Subject: LF: QRSS OP WSPR
Bob,
For QRSS reception on 4000m, better ask G4WGT or
F5WK or F6CNI for a preferred frequency. Ort maybe TF3HZ? He is reading the
reflector as well. At least i saw the flag from Iceland on the flagcounter of
SC8CS's new grabber which was announced here :-))
BTW, regarding OP65,
Jay/W1VD recently did some tests comparing OP4 and WSPR-2. The summary was
something like "WSPR-2 is as "sensitive" as OP8" !!. Correct me Jay. That
means, instead transmitting OP65, you could use WSPR-15 instead and may have 4
times higher probabbility to get a decode, e.g. if there is just a short
propagation window like on 137 kHz.
73, Stefan
Am 27.09.2013
15:55, schrieb Bob Raide:
Stefan;
It is same here. But you can't do
everything-transmit and receive at same time no go.
I have a
similar PC got from neighbor last season a Samsung less than two years
old. Big difference from little ACER PC!
I think I am going to
stick with QRSS 60 for anymore 73 kHz work. What freq might be
best for UK/Euro work? I understand that 72.4 is not good in
UK/Europe. Seems that 74.5-74.6 seems best from comments I am
getting?
Any suggestions
appreciated-Bob
