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Author Topic: OK, I'm stupid when it comes to propagation data.  (Read 1736 times)
W9KDX
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Posts: 770




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« on: March 10, 2012, 06:00:50 AM »

This should not be so hard.  I keep doing searches to try and understand a few of these numbers, but no one seems to use the same terminology.  One time it is SFI, then the ARRL article refers to SFU.  I look at SN, but no, it is not Solar Number but Solar Flux.  Is the "F" SFI a measure of flux or flare? 

I give up, help me out.

Just for SFI, what is it and is more or less better?

I have the rest of the terms figured out, but the first one listed in the prop gadget is a mystery.  He also seems to have changed the number system for electron and proton flux, but I'll get that figured out.

Thanks
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Sam
W9KDX
K8AXW
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Posts: 3594




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« Reply #1 on: March 10, 2012, 08:53:12 AM »

Sam:  Please don't feel like the Lone Ranger on this!  I've been doing battle with the same problem for decades.  I study the numbers, learn the meanings and by the time the next set comes out I've forgotten what I learned.

I've downloaded and printed out graphs of what frequencies to use on what band during what part of the day.  I seldom see any correlation so just turn the damn radio on and swing the beam and hear what I can hear.  If I don't hear anything, I turn it off.

What would be great is if someone would just publish a simple graph for each band so one could see if conditions were getting better or worse.

Of course I understand this is an oversimplification of a complex problem...... but I do feel your pain Sam.  Rotsa Ruck!
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N6AJR
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Posts: 9879




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« Reply #2 on: March 11, 2012, 12:02:41 PM »

look up some of the books and articles from Dean Straw.  he knows this stuff front to back, and is a good explainer too.  he use to work at arrl and has hand a hand in lots of related books.
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WA2ONH
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Posts: 246




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« Reply #3 on: March 11, 2012, 01:41:32 PM »

Some added info / eBook available at these sites:

G0KYA's FREE Propagation eBook (approx 1mb) at:
LINK: http://www.infotechcomms.co.uk/Understanding_LF_and_HF_propagation.pdf

G0KYA's Blog at:
LINK: http://g0kya.blogspot.com/

K9LA Carl Luetzelschwab's Amateur Radio Propagation Web Site at:
LINK: http://myplace.frontier.com/~k9la/

Finally, here's a write up by Paul Hardin NA5N from 2005 FDIM:
LINK: http://www.qrparci.org/mambo/pdf/FDIM81.pdf

Hope this fills in more pieces of the puzzle. Good Luck.
« Last Edit: March 17, 2012, 02:55:19 PM by WA2ONH » Logged

73 de WA2ONH dit dit    ...Charlie
----------------------------------------------------------------------------
"No time is ever wasted that is spent LEARNING something!"
KL3HY
Member

Posts: 117




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« Reply #4 on: March 12, 2012, 01:23:43 PM »

A guy that has helped me out quite a bit with HF pointed me to this site:

http://www.voacap.com/coverage.html

It's a very cool propagation prediction map.

Mike
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K7MH
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Posts: 328




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« Reply #5 on: March 13, 2012, 08:00:51 AM »

SFU is solar flux unit(s). SFI is the solar flux index.
A SFU is a measurement standard, The SFI is the level the solar flux is at and being reported.
Basically they are used the same way. IF the SFI is 150, then it is reporting a level of 150 Solar flux units.
Higher is better.
A index and K index you want to see as low.
We want sunspots (cooled spots on the sun) but no flares as they raise the A and K levels.
Unfortunately sunspots can give way to solar flares.

Here is a good simple explanation;
http://www.k7pt.com/solarphp.php
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WA4IIF
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Posts: 108


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« Reply #6 on: March 14, 2012, 04:06:13 PM »

Check this link for some good explaining: http://www.qsl.net/w2vtm/hf_solar.html.
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W9KDX
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Posts: 770




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« Reply #7 on: March 16, 2012, 04:00:16 PM »

Thanks guys.  Those sources cleared up a lot.  That vaocap site is amazing.
« Last Edit: March 17, 2012, 05:28:40 AM by W9KDX » Logged

Sam
W9KDX
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