Jack, I think you could, if you're willing, have a very fruitful
conversation with Alex, VE3NEA. I know a little bit about the
techniques he's using to assess the plausibility of a given prefix and
suffix, but you have "been thereand done that" , and I think it would be
a great contribution.
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.
On 2/19/2013 2:52 PM, Jack Haverty. wrote:
In the spirit of improving accuracy....a suggestion
In the late 1970s, I was involved in a project to use computers to
understand Morse code. Google "haverty understanding Morse code" if
you're curious.
We struggled with the same kind of inaccuracies that Skimmers are now
experiencing. We used many independent techniques to generate plausible
decodings from what came off the antenna plus lots of ancillary
information, like dictionaries, and "common sense" like expected
propagation behavior and current band conditions.
The key technique in making the final decoding very accurate was that each
module that generated an "opinion" about what was being decoded also
attached a "confidence" to that opinion. So, a suggested decoding from an
S9+30 signal with little QRM/QRN/QSB would have a higher confidence than a
S2 signal in the middle of a crowd with summer static conditions. A
decoder might look at a few seconds of signal and suggest that the sender
said "E5EEE", but if it was a strong signal it would have a very high
confidence level and if a weak one very low.
That "confidence" factor enabled other modules further down the line to
make more intelligent decisions about the most likely decoding. For
example, a subsequent "callsign module" might look at the decodings
suggested by the earlier "dot/dash decoders", and conclude that "E5EEE" was
not very likely, especially if "E5EEE" had been decoded with low
confidence. It would offer its own opinion about what the signal contained
-- for example that it was just noise.
If the Skimmers could produce spots that contained not only a callsign but
also a "confidence", consumers further down the line (e.g., contest
programs displaying spots) could filter those spots based on confidence -
e.g., only display spots that are high confidence.
Perhaps a spotting network convention like <callsign>.<confidence> -- so
spots would come out across the spotting network looking like "E5EEE.2" or
"EK3LR.4", or "K3LR.9" or something similar. Logging software receiving
such spots could apply their own heuristics, e.g., by consulting a list of
known contest callsigns, and decide whether or not to display the spot to
the operator.
73,
/Jack de K3FIV (not VK3FI as I am sometimes labelled....)
On Feb 19, 2013 9:46 AM, "Shane Mattson-->K1ZR" <k1zr@comcast.net>
wrote:
I'm starting a new thread for increased visibility to this issue.
This is by no means a skimmer bashing post, so please don't go there..
I'm just curious if others have observed the following:
Just for kicks I performed a RBN spot search for my call and the following
spots came up during a period of time that I was QRT. I did not operate at
all on Sunday.
de dx freq cq/dx snr speed time
K3LR K1ZR 28005.3 CW CQ 13 dB 32 wpm 2042z 17 Feb
K3LR K1ZR 14046.6 CW CQ 24 dB 31 wpm 2014z 17 Feb
KM3T K1ZR 14046.6 CW CQ 15 dB 33 wpm 2011z 17 Feb
VE2WU K1ZR 14046.6 CW CQ 20 dB 31 wpm 1927z 17 Feb
K8ND K1ZR 21006.9 CW CQ 8 dB 32 wpm 1743z 17 Feb
NY3A K1ZR 28062.4 CW CQ 28 dB 31 wpm 1654z 17 Feb
K2DB K1ZR 7020.5 CW CQ 10 dB 29 wpm 0855z 17 Feb
K2DB K1ZR 7020.4 CW CQ 11 dB 30 wpm 0753z 17 Feb
K3LR K1ZR 3510.3 CW CQ 26 dB 29 wpm 0207z 17 Feb
Perhaps the skimmers misinterpreted a like-call sign? I'm not excited
about
seeing my call detected and spotted during a period for which I was QRT.
An
issue like this emphasizes the importance of double checking the call sign
for accuracy before logging a point and shoot qso.
Could someone within the RBN domain provide some insight as to how to
address an issue like this?
-Shane
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