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Author Topic: Low SFI and bad band conditions  (Read 1020 times)
SWMAN
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« on: May 26, 2011, 04:01:30 AM »

Does anyone know or have an idea why in these times when the suncycle is suppose to be on the rise and band conditions should be getting better conditions are getting much worse. The SFI has been dropping in numbers everyday.Lots of noise on most HF bands and poor communications. I thought that the rise of sun cycle 24 should be making things much better? The SFI today is only 80. Thanks and 73 Jim. W5JJG
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N3QE
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« Reply #1 on: May 26, 2011, 04:11:21 AM »

Earth weather has a lot to do with the atmospheric noise. US Midwest has had persistent thunderstorm conditions for a good while now.

Summer is coming up, ham activity drops off as folks go on vacation, and there's an upcoming HF contest this weekend that is often preceded by a little lull in activity too. In the past few weekends there have been some VHF contests "sucking away" some HF activity too.

I'm already hearing a couple of the well known contest stations "Warming up" for this weekend's CW contest.

All that said, in the past couple of weeks 15M, 17M, and 20M have obviously been open later and later into the evenings.
« Last Edit: May 26, 2011, 04:31:17 AM by N3QE » Logged
SWMAN
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« Reply #2 on: May 26, 2011, 04:29:47 AM »

Thanks Tim, but why do the Solar Flux Index numbers keep dropping every day?
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N4CR
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« Reply #3 on: May 26, 2011, 04:35:49 AM »

Because the sun is putting out less solar flux.

Nobody knows why.
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73 de N4CR, Phil

Never believe an atom. They make up everything.
N3QE
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« Reply #4 on: May 26, 2011, 04:36:19 AM »

Thanks Tim, but why do the Solar Flux Index numbers keep dropping every day?
While there is a very real upward trend over months or years in this part of the cycle, on a day to day basis a "quiet sun" will bring the numbers up and down.

Statisticians have shown surprisingly strong correlation in the variableness of the sun and the variableness of the stock market :-).
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SWMAN
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« Reply #5 on: May 26, 2011, 05:45:57 AM »

Ok, Got cha !and thanks!
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N3OX
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« Reply #6 on: May 26, 2011, 06:07:55 AM »

Take a look at how much variability there is on the plots here:

http://www.swpc.noaa.gov/SolarCycle/

The purple curves are the monthly averages.

You have to "low pass filter" over many, many months in order to stop seeing big excursions away from the overall trend.   The variation inside any given month is even more extreme.  Lots of up and down is normal, but we're trending UP over a long time. 
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
WA3SKN
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« Reply #7 on: May 26, 2011, 10:29:27 AM »

17, 15, and even 12 meters have been open within the last week.
I heard Tahiti last week on 12 meters louder than the locals.
17 was staying open after midnight locally for the European stations.... a nice sign of things to come.
You might want to make sure your antenna has a low angle of radiation, though.  If it is a "cloud warmer" you might have a problem!
73s.

-Mike.
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KB9CRY
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« Reply #8 on: May 26, 2011, 10:38:45 AM »

Does anyone know or have an idea why in these times when the suncycle is suppose to be on the rise and band conditions should be getting better conditions are getting much worse. The SFI has been dropping in numbers everyday.Lots of noise on most HF bands and poor communications. I thought that the rise of sun cycle 24 should be making things much better? The SFI today is only 80. Thanks and 73 Jim. W5JJG



It's Summertime !!!
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