Roger, VLF,
I will check the resonance curve in the next experiment. Maybe it is
higher than expected due to the high R in that RLC-circuit... So maybe
there are even some many Hz available...
Stefan/DK7FC
Am 30.07.2010 09:58, schrieb Roger Lapthorn:
Andy,
Would a variant of WSPR be possible that uses a slower FSK rate over,
for example, a 4 minute TX period? Would a half speed WSPR convey the
same data in twice as long but only occupy 3Hz bandwidth? This of
course assumes K1JT has nothing better to do!
73s
Roger G3XBM
On 30 July 2010 08:54, Roger Lapthorn <[email protected]>
wrote:
Presumably
"QRSS very very slow" is better still, but here this issue is the time
to get data through. Andy, I assume that you're saying WSPR or JT4A
give the best "data per bandwidth per given time"?
73s
Roger G3XBM
On 30 July 2010 08:17, Andy Talbot <[email protected]>
wrote:
Try WSPR at 6Hz bandwidth or JT4A at less that 20Hz. They
are both MSFK constant envelope schemes.
2010/7/29 Stefan Schäfer <[email protected]>
Andy, LF,
Which digital mode could be most suited for a band where one has just
an antenna bandwidth of some Hz? You know what i mean... And what could
be the "gain" compared to DFCW-600. Gain means here, how far(er) could
it be detected, not how much more information can i transmit within the
same time.
73, Stefan/DK7FC
PS: I see that e.g. JT65 needs abt 200 Hz, so this NOT suited!
Am 29.07.2010 23:07, schrieb Andy Talbot:
It would be very interesting to see those figures
normalised to a constant data rate / bandwidth. For example, PSK31
shown at -10dB is identical to PKK63 at -7dB - well it would be, its
the same modulation, just faster. Ie plot Bits/second/Hz vs. Eb/No,
then stick the Shannon limit on the graph and see which lie nearest.
The fact that JT65 is at the top is probably because it
sits at around 0.27 chars / second, or something like 1.2 B/s.
Although even after normalisation, it would no doubt still score well
up.
--
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G3XBM GQRP 1678 ISWL G11088
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