Thanks, Doug - you explained the pitfalls of running Skimmer against the
pileup tape better than I could have.
The issues involved with implementing CW Skimmer in a practical contest
station configuration will be the subject of a long article in the Sept-Oct
NCJ that I'm currently writing, If anyone has any recommendations or
comments, please send them to me.
73, Pete N4ZR
>Doug wrote:
>So let me summarize my observations about Skimmer as seen live this
>past weekend:
>
>1. The vast majority of the 100+ people who raised their hands at the
>Contest Forum to signify that they had posted an opinion on Skimmer to
>this reflector admitted by lowering their hands that they had never
>actually seen the thing demonstrated before.
>
>2. Skimmer was not really designed for the case of decoding two
>simultaneous close-spaced signals in a narrow audio band (the KCDXC
>signals are all between about 300 and 800 Hz). I suspect if VE3NEA
>chose to play with that specific case, the Skimmer would do better. Or
>maybe someone else will want to take up the challenge.
>
>3. I think this is a pretty cool addition to the KCDXC competition. It
>is like those competitions between human and computer chess players.
>Perhaps we can set aside a run for machines for next year...just like
>the 6-human runs, we can have 6 machines plug in.
>
>4. There was a lot of excitement when the Skimmer score was being
>announced. Some people were concerned that it might have beaten the
>humans...maybe by a lot! I had talked to W9WI and a couple of the
>other guys who usually are at the top of the list before the
>competition, and told them that they were tasked with preserving the
>dignity of the human race. They of course, delivered the goods. Nice
>job! There was a very loud cheer when KU1CW posted the number.
>
>5. What Skimmer is intended to do is look at a wide bandwidth and
>decode a lot of signals simultaneously. It does that very well. Here
>is the data point from the wideband recording of the 40M band during
>the 2007 CQWW: in a 1-minute 45-second period, the Skimmer decoded
>(and put in bold) 157 callsigns spread out over the band. Rounding a
>bit, this is about 100 callsigns per minute. No human tuning a
>receiver can do that. I estimate that a skilled human can probably
>tune in and identify a new QRM-free station on an active band in about
>3-4 seconds. That means 15-20 per minute, compared to Skimmer's
>100/minute rate. And if you have several Skimmers on different bands,
>the gap widens, since the human does not scale with more signal
>inputs.
>
>6. The Skimmer is still in development. I understand that work is
>underway to integrate the SCP database and the K1TTT callsign pattern
>algorithm to improve the accuracy and filter what gets displayed.
>
>So I guess the moderators will allow the debate to restart, and now
>that more people have actually seen the monster, they can post more
>informed opinions. Maybe nobody has changed their opinions, but at
>least they have a few more facts.
>
>Thanks to N4ZR and N6TV for providing most of what I presented at the
>Contest Forum, including all the test files, and to the KCDXC folks
>for allowing me to run the Skimmer at their suite.
>
>Hope everyone had a good time at Dayton and got home safely. See you next
>year!
>
>73,
>
>Doug K1DG
>
>p.s. I'll put the Contest Forum slides on line. QRX a few days
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