Audio of Eric from 3B9C and my almost QSO:
kkn.net/n6tr/160/3b7cQSO.mp3 <https://www.kkn.net/n6tr/160/3b7cQSO.mp3>
On Fri, Nov 22, 2024 at 1:21 PM Eric Scace K3NA <eric@k3na.org> wrote:
> 3B9C — yes, I was there. But I don’t recall working 160m SSB, just CW. I
> did work a couple of long-path QSOs with the west coast on top band (west
> coast sunrise, 3B9 sunset).
>
> It was interesting to see the delay from when 160m closed in the morning…
> to 80m CW closing… and then finally 75m SSB. The 10%+ difference in
> frequency between 80m CW and 75m SSB was obvious.
>
> > On Nov 22, 2024, at 06:44, kq2m@kq2m.com wrote:
> >
> >
> > Hi Eric,
> >
> > Thank you for explaining that! I always wondered how it was possible
> that I worked such a loud 3B9C (honest S9) on 4/12/04 at 0012z on 160 SSB!
> Were you on that DXpedition?
> >
> > I also wonder if this phenomenon of ducting would explain my JA qso's on
> 160 which were made 1st call through a pileup of W4 /W9 shortly after dawn
> some years ago? The likelihood of my ever beating out a W4 or W9 to JA on
> 160 is ZERO, so some rare and unusual propagation effect was at work.
> >
> > 73
> >
> > Bob, KQ2M
> >
> >
> >
> >
> > On 2024-11-21 21:47, Eric Scace K3NA wrote:
> >> Hi Ron —
> >> See attached image of the twilight zones at 00:40Z today. You will
> see that 3B9 is in the middle (nautical) twilight zone band… and the
> twilight zones cross North America.
> >> Having worked this path myself from 3B9, I can testify to how cool it
> is. Ducting explains part of why the signal was so loud when you heard them
> — ducts are very low loss conduits for signals at the ducting frequency
> range. But escaping from a duct requires the signal to encounter some
> less-ionized part of the floor of the duct, so that the signal can continue
> down toward the earth’s surface. And the exit point still has some
> refraction, so the signal may exit the duct at a very shallow angle and
> travel a long way before it reaches the surface.
> >> These thin spots are indeed spotty, transient, and move around.
> >> When I was on 3B9, clumps of geographically-adjacent stations would
> get worked — a spot corresponding to a weak spot in the duct. Some clumps
> were clearly connected to each other by an added ionospheric hop in the
> normal way. We could plot this clumps over time and see them move along
> with the terminator… but eventually (minutes or tens of minutes) a
> particular “leak” would close up. Maybe we had several “leaks” at one time,
> working different spots in North America… and sometimes no leaks at all.
> >> So yes — spotlight propagation.
> >> This emphasizes why it’s important for a DXpedition to be on top band
> every night. Some nights will have no ducts. Others with have leaky ducts —
> but the leaks will only illuminate certain patches of North America (in
> this case)… and on another night different patches of North America. To
> give everyone a chance, one has to be on every night. And for the person
> chasing the DX, one has to be listening every night until a leak/spot
> favors that person’s location.
> >> And then, as you experienced, it’s super easy to work each other
> through that low-loss path.
> >> — Eric K3NA
> >>> On Nov 21, 2024, at 19:37, Ron Spencer via Topband <
> topband@contesting.com> wrote:
> >>> Tonight (11/21) around 0040Z I saw a signal pop up on the panadapter.
> Tuned to it and its 3B9/M0CFW calling CQ. 15dB or more above my noise
> floor. I couldn't believe how solid and loud they were. After amp came on
> line I called and worked them. During the wait time I did a quick internet
> search to see if is indeed a real station. Yep.
> >>> What amazed me, and still does, is absolutely NO rbn or packet spots
> during the at least 5 minutes they were on. And no other callers. Even
> after I spotted them on packet and the kst chat page.
> >>> I have no explanation for this. Why no rbn spots? Why no other callers
> when they were very solid for almost the whole time they were calling CQ?
> Was this an example of very small spot light prop? There were others on so
> its not like no one was tuning the band. Baffling.
> >>> Below is a screen shot of their signal. they are in the red area.
> Received on my homebrew 8 antenna circle array with no preamp.
> >>> Perhaps someone out there has an explanation.
> >>> Ron
> >>> N4XD
> >>> Sent using https://www.zoho.com/mail/
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