Hi Graham,
> ... note Phil is also running RX and may
provide shortly a secondary , off-air decode
to provide a time stamp.
maybe this is not such a good
idea. When the timestamp from a local decode is propagated over the Opera web
link, all other active decoders immediately get this info. A sceptic (are
we?) could suspect that this might be used by the detectors to
correlate their last-received noise against the known message and
timeframe, using an arbitrarily low detection threshold - a la "You've
heard it too, haven't you? You surely have...". This could make false positives
very likely, but no one can tell them from a real one. The Opera
program then has four minutes (one on MF) to output such a
hit as a delayed dynamic deep search decode. afterwards, the matching
timestamps would be used to falsely "verify" a false detection,
which had really been provoked by exactly
that timestamp.
In my opinion, it would enhance
credibility to not propagate local decodes, but let the transmitter
only keep a "secret" log of their emissions. This could then be used in an
a posteriori comparison against correlation results, which
have been created independently without a priori knowledge of transmit
times.
All the best,
Markus
Sent: Friday, May 22, 2015 3:19 PM
Subject: LF: 477 VK5CV de VK2XGJ Op8 690 mi -17 dB F:8% in Dapto,
Austealia with 25w
|
