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E layer ionisation requirements in SFU.


hamateur 1953

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What's NRC?

The automatic SWPC algorithm for flare detection is documented in the Usage tab at: https://www.swpc.noaa.gov/products/goes-x-ray-flux

Successive flare activity may have prevented flare end time detection which is the point halfway between the maximum flux and the pre-flare background level.

Some flares may need to be identified manually.

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https://www.spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-flux-en.php  NRC is solar flux at 10.7 three samples per day. Digitally by numbers.  See link.  The far left column is used by Hams typically and Natural Resources Canada samples in our winter three times daily.  18:00 20:00 and 22:00  UTC.  Note: although penticton British Columbia is Pacific Time, Boulder Colorado is one hour later in our day.  In summer the spread of samples increases to 17:00 20:00 and 23:00 I believe.  

It is especially interesting to me. You can look at Growth thread and an unusual coincidence happened yesterday. I was speculating based on the Aug 4 1972 event that ionised the russian e layer all night that yesterday’s series of M flares might have a similar effect.  Emphasis on might!! I never really expected it to happen but apparently @KW2P witnessed the actual event live.  Way cool.  My point being that analog trumps digital ( except morse code of course!) any day. Because nuances can be seen easily. 

Edited by hamateur 1953
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O, Natural Resources Canada

I see your point.  We should have expected a higher 10.7cm radio flux value at 2024-01-23 20:00 UTC in particular when there was a M 1.02 in progress.

The 10.7cm radio flux (2.8E9 Hz) and GOES X-Ray flux (1.0E18 Hz) are usually in sync.  If the data are correct, perhaps there is occasional divergence depending on the specific solar event - i.e. different frequencies measure somewhat different phenomena, or measure the same phenomena somewhat differently?  Maybe these flares were dimensionally too small to register significantly in the 10.7cm sensor?

Edited by Drax Spacex
Natural
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I think the flux actually dipped down to baseline levels briefly.  Our smoothing probably concealed these events.  It was interesting to me that NRC hit it all three times incredibly.   A few months ago @Philalethesand me had a good chuckle when seeing over 800 sfi during the declining of an X flare event I think it was.   Frankly, I couldn’t imagine how they missed all three intervals!!

3 hours ago, Drax Spacex said:

O, National Resources Canada

I see your point.  We should have expected a higher solar flux value at 2024-01-23 20:00 UTC in particular when there was a M 1.02 in progress.

The 10.7cm radio flux (2.8E9 Hz) and GOES X-Ray flux (1.0E18 Hz) are usually in sync.  If the data are correct, perhaps there is occasional divergence depending on the specific solar event - i.e. different frequencies measure somewhat different phenomena, or measure the same phenomena somewhat differently?  Maybe these flares were dimensionally too small to register significantly in the 10.7cm sensor?

Oh yeah not Natural. Haha  hey Drax Im not sure which is which!! Natural or National!!  I’d better check now!  Haha 

Edited by hamateur 1953
Canucks
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It was certainly one of the more interesting things I have heard about since joining this site a little over two years ago.  Being a terrible procrastinator and because SFI hasn’t hit the 250 mark I think it might take to cross the United States on the upper level (F2 ) of our ionosphere on the Amateur frequency of 50 mhz.  I kinda gave up on the idea a bit ago, and definitely missed another fun event.  No matter, this cycle has lots more fun in store and surprises of that I have little doubt.  Now where is that coil of RG 8x coaxial cable??  Hahaha 

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Actually it is Natural Resources Canada!  Thanks for the link.  Yes higher SFI should open up 50MHz to the average HAM station which includes me, with 100W and a wire.  I made 3 contacts in the 6m (50MHz) band in one day last year, 2023-06-11, from IL, VA, and MN.  SN=116 and SFI=154 on that day - not too impressive.  But it was a contest weekend, and the contacts I made were running power (1kW) and had some very well-tuned directional antennas mounted on tall towers.  Sporadic E no doubt in play as well.

Simultaneous flares from different ARs can also complicate flare detection and association.  Manual analysis is often required in such cases to sort them all out!

Edited by Drax Spacex
6m
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  • hamateur 1953 changed the title to E layer ionisation requirements in SFU.
16 hours ago, hamateur 1953 said:

I just realised that unless someone smarter than me has already done this before, that if we are able to calculate the days net solar flux vs time, we should know pretty much what it takes to make our e layer a good performer and at what frequency range.  Cool stuff.    Further editing:   I’ve asked a relative of mine and another on this site to look into this to see if a simple ( ha) calculus equation might allow us a prediction lead of three or four hours on these events as a beginning.  I may have something in a few days here for all of us hams.  Mike/Hagrid 

It's fairly simple to get a very rough approximation of the fluence (energy per square meter, also known as radiant exposure) for the day through numerical integration, which can then be divided by the number of seconds in a day to get the average flux. Using the trapezoidal rule I get a fluence for 2024-01-23 of ~0.465 J/m^2; dividing this by the 86,400 seconds in a day we get an average flux of ~5.384 * 10^(-6) W/m^2, which is equivalent to a steady ~C5.4 background flux.

As a sanity check I did the same for 2024-01-19, a much calmer day, and got a fluence of only ~0.084 J/m^2 for an average flux of ~9.755 * 10^(-7) W/m^2, equivalent to a background flux of ~B9.8 (rounded up). All in all I think an average flux of C5.4 is in fact quite high, even though it might not immediately stand out as such.

All of that being said I don't know if that ultimately gives the whole picture in terms of how the ionosphere responds and its results for ham radio; there could be nonlinear dynamics in the system (e.g. 12 hours of a steady C1 followed by 12 hours of a steady C9 not necessarily leading to the same ionospheric response as 24 hours of constant C5, and so on).

Looking at NOAA's values for the actual background fluxes here it's also clear that it's not simply an average calculation like that above (the approximation isn't perfectly accurate, but it's not that inaccurate), but that the actual background is lower, while the flaring that raises the average isn't counted towards it (which is the point of having a notion of a background flux in the first place). Presumably the ideal F10.7 measurement is meant to be a reflection of this steady background flux, but I assume it's not that easy to extricate it from all the flaring on very active days. Here are the background flux values from the above link at the beginning and end of the two days in question for future reference (since that link is constantly updated with the latest values), corresponding to ~B7.4 to ~B7.5 and ~C2.1 to ~C1.5 respectively, quite a bit lower than the actual average flux for the days due to all the flaring:

Quote
{"satellite": 16, "time_tag": "2024-01-19T00:00:00Z", "background": 7.357582357296147e-07}
{"satellite": 16, "time_tag": "2024-01-20T00:00:00Z", "background": 7.51765094264556e-07}

{"satellite": 16, "time_tag": "2024-01-23T00:00:00Z", "background": 2.111754554334766e-06}
{"satellite": 16, "time_tag": "2024-01-24T00:00:00Z", "background": 1.5392680552395177e-06}

 

Edited by Philalethes
clarity
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10 minutes ago, hamateur 1953 said:

The ability to predict with reasonable accuracy the available frequency and distances achievable is all that is really necessary for most of us radio amateurs. This is a hobby for most of us, although there are many in the broadcast industry etc at a technical level.  It’s the challenge that most of us get a kick out of.   For myself, I build projects etc amplifiers etc  If you read Draxs posts, you might have been amazed that he worked Morocco from  the states a bit ago.  That is pretty amazing for 100 watts of RF power.  It’s the unusual and unexpected like an X-20 that many Hams might just gripe about, like I did long ago, not realising that if I were only to change frequencies, not only would the horrible racket quiet down, but I might just make a historical contact and inadvertently add valuable information to amateurs and professionals alike.  Tnx for comments all of y’all haha   Gotta get some shut-eye soon   73s. Mike/Hagrid

That certainly sounds like it would be quite useful indeed when engaging in such a hobby! Given the aforementioned findings about the average flux, you could always try to check if there's a similar value for future occurrences, i.e. an average flux of around ~C5; if there turns out to be, then maybe you could start to anticipate a future ham radio bonanza when the average flux starts to approach and/or surpass this.

In case you'd like to monitor it, I've set up a script to quickly check it every hour and to upload the value here if it's higher than C3 (populated it with a C1.8 to test, which won't change until the value exceeds C3 at some point in the future). So if there's a lot of activity and you suspect the average flux might hit that threshold, you should be able to check it there and prepare accordingly.

Of course there might be more complex factors that lead to favorable ionospheric conditions, but I guess it's a start.

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After much reflection ( pun intended) and talking with my younger brother a math whiz, I have decided that the problem looked deceptively simple in a word.  Every time I added a variable the problem became exponentially worse!!  Nuff said.  73. N7ORL Mike/Hagrid.   Ha.  I may revisit this in six months when I forget how ignorant I was before.  Haha

Edited by hamateur 1953
Humour
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1 hour ago, hamateur 1953 said:

After much reflection ( pun intended) and talking with my younger brother a math whiz, I have decided that the problem looked deceptively simple in a word.  Every time I added a variable the problem became exponentially worse!!  Nuff said.  73. N7ORL Mike/Hagrid.   Ha.  I may revisit this in six months when I forget how ignorant I was before.  Haha

There are at least 8 variables to factor in a mammoth task indeed.

-.

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10 hours ago, hamateur 1953 said:

After much reflection ( pun intended) and talking with my younger brother a math whiz, I have decided that the problem looked deceptively simple in a word.  Every time I added a variable the problem became exponentially worse!!  Nuff said.  73. N7ORL Mike/Hagrid.   Ha.  I may revisit this in six months when I forget how ignorant I was before.  Haha

Maybe I misunderstood what you were asking about in the first post, but I thought you were looking to calculate the daily average flux, hence what I posted earlier; perhaps you could clarify what you were going for.

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3 hours ago, Philalethes said:

Maybe I misunderstood what you were asking about in the first post, but I thought you were looking to calculate the daily average flux, hence what I posted earlier; perhaps you could clarify what you were going for.

Your answer was excellent @Philalethes   And should work in the manner described.  With observations using NVIS ionosounding ( which I lack) And maybe a staff of five or so spread out over the United States and identical linked ionosounding at each of their respective locations.  We just know so little about the true character of the e layer that I began to realise that while it appeared easy to chop out and analyze a chunk of empirical data the realistic thing is that I’d be fooling myself unless a lot of really sharp people who knew a heck of a lot more than I do had enough smarts and enough time to waste on what many see as a bizarre hobby. To wit:   “Man, you were born when intercontinental communications cost money and was totally unreliable Mike!! “.  “ If ya If ya see what I mean Captain”  (jk) (From Star Trek Scotty to  Kirk”. ). Apologies to Late Gene Roddenberry.   73. Mike/Hagrid  

the daily average flux can be calculated using your methods, to append this properly.  Its the application of it,    that’s the rub…. Note:    NVIS.   Near Vertical Incidence    Transmitting.  Think of   A surface vessel pinging upwards in a narrow beam to map a skyfloor for the quickest analogy I can dig up at 0400  Seattle time. Haha. 

Edited by hamateur 1953
Clarity
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35 minutes ago, hamateur 1953 said:

Your answer was excellent @Philalethes   And should work in the manner described.  With observations using NVIS ionosounding ( which I lack) And maybe a staff of five or so spread out over the United States and identical linked ionosounding at each of their respective locations.  We just know so little about the true character of the e layer that I began to realise that while it appeared easy to chop out and analyze a chunk of empirical data the realistic thing is that I’d be fooling myself unless a lot of really sharp people who knew a heck of a lot more than I do had enough smarts and enough time to waste on what many see as a bizarre hobby. To wit:   “Man, you were born when intercontinental communications cost money and was totally unreliable Mike!! “.  “ If ya If ya see what I mean Captain”  (jk) (From Star Trek Scotty to  Kirk”. ). Apologies to Late Gene Roddenberry.   73. Mike/Hagrid  

the daily average flux can be calculated using your methods, to append this properly.  Its the application of it,    that’s the rub….

I guess a place to start could be to just go with trusted reports of the E-layer activity you described above (and any of your own observations of it, of course), rather than actual measurements, and to compare the times such reports occur with preceding flux activity. Maybe you could get some ideas about the relation that way, without needing to go too deep into it.

Edited by Philalethes
typo
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1 minute ago, Philalethes said:

I guess a place to start could be to just go with trusted reports of the E-layer activity you described above (and any of your own observations of it, of course), rather than actual measurements, and to compare the times such reports occur with preceding flux activity. Maybe you could get some ideas about the relation that way, without needing to go to deep into it.

A better suggestion indeed!  Haha! 

I feel compelled to add this brief note while keeping my ego in check I hope.

Hams have been around since the turn of the last century. We are driven by curiosity and public service in emergencies.  I have previously worked with the Red Cross and others. We do our emergency work without expecting compensation. It’s nice to feel appreciated Haha.  73. Mike  

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