[Lowfer] OP65 late start for tonight-73 dial as usual...

[JD]

>>> past receptions of DK7FC make it clear that deep search has a real 
>>> sensitivity advantage over regular opera.

IMO, that's going to depend on how you define sensitiviy.  It's hard to say 
anything definite when the inner workings are kept obscure, but so far as 
extraction of actual signal from noise in a comparable bandwidth, it's 
almost certainly not that.  The same physics is at work either way.  It's 
reasonable to infer that OP "deep search" has much the same meaning as it 
does with WSPR, in that whatever parts of a signal are recovered in the 
traditional sense get compared to a database of expected calls and locators, 
and a probable hit is reported when enough pieces match.

It's like when I tune near WI's frequency on 1750m and see a broken carrier 
drifting in the same manner I expect of WI.  By "deep search" standards, 
that's a possible spot.  If I knew from reading someone else's post that WI 
was definitely on that night, I could bump that up to a probable spot.  And 
if I could point to one interval that looked distinctively enough like a "W" 
or an "I" then I'd be able to claim certain copy.  Simply in probabilistic 
terms, the odds are that I'd be right most nights.

But in real life, I would never report such a shaky result as definite copy 
of WI.  I'd consider that akin to cheating, because (a) it couldn't be done 
without foreknowledge of the information being sent, and (b) there's still a 
small but realistic chance it could be completely wrong.  Even if I were 
right about it being WI but there were some other message contained in the 
signal, I'd never copy it under the same circumstance.

Thus, I would suggest that sensitivity comparisons between modes are only 
meaningful if the information being transmitted is not known ahead of time, 
including (or maybe, especially) by a third party with whom both the 
sender's and receiver's computers communicate across the Internet.

73
John