[Moon] Deep Search IS cheating

Stephen Hanselman eme at kc4sw.com
Sat Aug 23 02:55:48 CEST 2014


You all understand that if we go back to the beginning of EME not only were the contacts CW they were scheduled in advance and paralleled on 20 meters in real time, see W6PO's et.al. log book entries

So there....

By the way un-subscribe me from this list I'm tired of the BullShit from a few

73's
 
Stephen Hanselman, KC4SW
Datagate Systems, LLC
3107 North Deer Run Road #24
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s.hanselman at datagatesystems.com
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Sent from my iPad

> On Aug 22, 2014, at 2:05 PM, Leif Asbrink <leif at sm5bsz.com> wrote:
> 
> Hi All,
> 
> I do not read many of the postings in this discussion because
> mostly the technical level is very low - or non-existent.
> 
> There is however one point that I think needs to be considered
> when the CW cheat-sheet is compared to deep search.
> 
> With the limited lists of today, knowing 3 characters might be enough
> to pick a station from the CW cheat sheet. I suspect people do not
> really do that because once one has found a candidate one can
> listen a little longer and then the sensitivity is much better
> because one "knows" what to expect. Based on that one has "heard"
> the full call sign.
> 
> To understand the fundamental difference, assume that the cheat sheet
> as well as the call3.txt database contains all the 2(?) million
> call signs issued worldwide. JT65 would not be affected, but 
> the cheat sheet for CW would be totally useless.
> 
> The deep search in JT65 would not be affected. The more different
> call signs that are compared to the received data the better.
> Ideally the received data should be compared to all possible
> messages. The matches should form something like a Gaussian
> distribution. If there is one single message that shows a 
> significantly better match than any other message and provides a 
> data point that is unlikely to belong to the Gaussian distribution
> a detect made.
> 
> When the call3.txt list is limited like it is today, the number of 
> points on the Gaussian distribution is not very large. That may
> add some uncertainty in the exact form of the tail of the curve
> and make it a bit uncertain how far out a match has to be to be '
> considered a detect.
> 
> In the past, maybe 7 years ago and earlier, detects were based on
> the absolute value of the match. That caused false detects sometimes
> because the entire Gaussian may shift a little with different
> received signals (when they contain interference that is not white 
> noise.) I do not remember any details, but I am sure Joe could tell
> if someone would be interested.
> 
> I personally think that neither call3.txt nor the CW "cheat sheet"
> is cheating. I consider both as legitimate tools to improve sensitivity.
> 
> I do however consider the usage of scheds as cheating. Both in CW
> and in JT65. I have solid experience of cheating in CW before the
> JT era. I was the only station with full polarization control.
> I always heard all stations having a single yagi and 500W or more.
> There was a sched list on the Internet every month and I used it
> to find stations I never worked before. (Newcomers who only
> used scheds.) I would listen and after maybe 2 periods I would
> know that the sched partner is QRT. That happened now and then.
> I would call the interesting station KH6ABC de SM5BSZ SM5BSZ 
> SM5BSZ. The result was always (except once with a VK station)
> that the interesting station would send the call of his sched partner
> and then OOO OOO OOO. I would continue sending mostly my own call
> and the other station would continue OOO to his sched partner.
> After 10 minutes I would quit.
> 
> It is OBVIOUS that most sched QSOs are based on "someone is on
> the frequency so it must be my sched partner" I know for
> sure that I produced a strong signal with the correct polarization.
> The sched station just did not care to listen (or did not know CW)
> 
> I have done this test about 10 times and 1 in 10 for not cheating
> is a very discouraging result. I actually think the integrity 
> of JT65 contacts is better provided that there is no parallel
> Internet communication.
> 
> I think, contrary to use lists, that basing the identification
> on the presence of a signal on the correct frequency is cheating.
> 
> Random contacts are fine CW as well as digital as I see it.
> That does not mean that I consider a DXCC with JT65 anywhere
> as valuable as one with CW only.
> 
> The big stations can produce SSB that is easily heard by most
> stations. Mixed mode JT65/SSB should be more common. Mixed mode
> JT65/CW is of course technically more feasible, but all JT65
> operators do not know CW...
> 
> Personally I find JT65 boring. The format is too restricted
> and it only allows collecting new stations like collecting stamps.
> 
> In the CW era, breaking the rules cleverly, was what made
> operation exciting!
> 
> 73
> 
> Leif / SM5BSZ
> 
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