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Heard on 75 AM




 
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Author Topic: Heard on 75 AM  (Read 5261 times)
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KL7OF
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« on: December 29, 2004, 10:29:37 AM »

Yesterday (29th) at about 1/2 hr before sunset in Tum tum.....I heard WA1HLR on 3870 calling CQ with no takers.....His signal was quickly building so I gave him a couple calls on the big rig.....He couldn't hear me...He was strong in here for about 30-40 minutes working stations in the middle of the country, and then faded away shortly after sunset......I have noticed this propagation several times this season at around sunset local time....
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K1JJ
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"Let's go hiking in the woods, Tommy!" - Yaz


« Reply #1 on: December 29, 2004, 11:41:42 AM »

Quote from: KL7OF
Yesterday (29th) at about 1/2 hr before sunset in Tum tum.....I heard WA1HLR on 3870 calling CQ with no takers.....His signal was quickly building so I gave him a couple calls on the big rig.....He couldn't hear me...He was strong in here for about 30-40 minutes working stations in the middle of the country, and then faded away shortly after sunset......I have noticed this propagation several times this season at around sunset local time....


Hi Steve,

This happens on 75M on other paths too.

A few weeks ago I heard the JA beacon from Tokyo [50KW] coming in here S9+10 from the southeast, longpath at about 4:45PM local. On 3799, Kan 7J4AAL from Hiroshima was calling "CQ North America" and coming in +10 also.   I called him many times with no response. Usually when he is this loud I get the same report from him.  No one from NA could get back to him that day. Then VK6LK came in louder than usual and he gave me a PW 4X5 report.

Sometimes the optimum take off angle going one way is very poor going the other way. Imagine if it was daylight here and I had to beam into a day lit ionosphere. Big attenuation. But then imagine someone on the other end in darkness beams into a dark ionosphere and his signal hits me coming down without needing a reflection in the day light area.

So in your case, perhaps your first hop was wasted into a day lit ionosphere and the Tron was using darkness the whole way. Simplified example, but you get the idea, esp during grayline areas on one end.

Another possibility is that maybe the ionoshere on your end, was not supporting an optimum first reflection at the proper angle. Whereas on Tim's end the ionoshere was different and supported that first angle outgoing.  Waves can take different paths to each station for sure. All of this variation is what causes fading, so it becomes almost a random thing. Probabiliity says that there will be times when both paths are perfect and everything else in between will occur over time too.

T
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WA2GEZ
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« Reply #2 on: December 30, 2004, 04:51:47 PM »

I am in JA land several times a year and was out in Nov.  I clearly heard K1JJ for about a 10 minute window one morning JA time.  Band goes long more than most people know, and God knows there is little out there to listen to anyway.  Bye Bye !
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