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Re: LF: MF 630m: False Decode or Real?

To: [email protected]
Subject: Re: LF: MF 630m: False Decode or Real?
From: g3zjo <[email protected]>
Date: Sat, 23 May 2015 11:14:02 +0100
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Wolf / LF

Don't you know that several of us are using Opera to reveal intelligent life in other Galaxy's, occasionally we do get a random two bit number. We are now desperately trying to get an internet connection, then we will know, Who they are, Where they are, What Power they are running, The antenna used, The distance to their planet and When the message was transmitted.
Like yourself because of the internet information exchanged, even prior
to deep search, I lost interest in the the mode for Amateur Radio.
But its great for comedy, like part quoting a statement in RadComm
proves that WSPR produces false decodes which makes Opera legit. I don't
know of any case of WSPR producing a false decode with a valid Callsign,
Locator, Power and Time.
Quoting the rest of the paragraph makes it clear, ## such false (WSPR)
decodes are rare but they do happen. They can always be spotted: false
hits as the callsign (even if it has a valid prefix) is unlikely to
agree with the locator information field.##
Admittedly WSPR was ill conceived, it needs to have 5 data units not 4
to remove the need to use two transmissions to send commonly needed /P
etc. but its good and we are stuck with it until the next major
development comes along.
Opera has made a fool of too many vulnerable operators.

73
Eddie G3ZJO


On 20/05/2015 21:40, wolf_dl4yhf wrote:
Hi Jochen,

I think the discussion about Opera's own 'deep search' mode (or whatever the proper name is) was done here (or on "the other" reflector) over a year ago, and the main problem I see is that the 'real time web-based exchange' of currently active stations means fooling oneself. Consider this: You know there are only four possible callsigns which have been transmitting, so in reality the software only has to decide for a TWO BIT number. Much easier than "really" decoding the entire number of message bits in an Opera message.
In my very personal point of view, this 'real time web exchange of
stations (calls) which are currently transmitting' should not be used
at all.
For comparison, Markus' (DF6NM's) own deep search uses a quite large
table which is *static*, which means that his decoder has no chance to
play unfair (because it doesn't know who's currently active or not),
and it also doesn't know what others receive (over the internet). What
I don't know is how many stations are currently in that list, and thus
how many bits the algorithm effectively has to "decode" (well, it
doesn't really decode, it also makes a best guess from a limited
number of list entries to chose from).
All the additional data which look as if they were "decoded" (eg
"VK3ELV ... 140w + Top loaded L 18m vert 80m horz") have been taken
from a database (***including the callsign***), not radio .. the only
real information is the '- 37 dB' report, and the two question marks
which imho may as well have been ten or twenty (considering the season
and the distance).
Well just my two pence of wisdom. I don't use Opera and don't think I
ever will.
Cheers,
  Wolf .



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