50 mhz F2

[hamateur 1953]

I have yet to be able to span the United States on six.   It should become possible using voice ( SSB) once flux gets near 200 for three days or so.  Was trying to reach @KW2Pby PM but unsuccessfully so far.  Not sure how many of us are on this site along our Atlantic seaboard ( I am near Seattle ).  73. Mike N7ORL    Fine to contact me by private message on this site.    In fairness, I estimate the odds of successful contact at less than 10% Ha Ha.  

Edited November 25, 2023 by hamateur 1953
Typo

[Newbie]

 

On 11/26/2023 at 1:18 AM, hamateur 1953 said:

I have yet to be able to span the United States on six.   It should become possible using voice ( SSB) once flux gets near 200 for three days or so.  Was trying to reach @KW2Pby PM but unsuccessfully so far.  Not sure how many of us are on this site along our Atlantic seaboard ( I am near Seattle ).  73. Mike N7ORL    Fine to contact me by private message on this site.    In fairness, I estimate the odds of successful contact at less than 10% Ha Ha.  

Unfortunately you are not having a lot of luck with flux. Hovering around 180 still as was mentioned. Everything seems to have settled back for the moment. 
It will pick up eventually.

N.

 

[hamateur 1953]

1 hour ago, Newbie said:

 

Unfortunately you are not having a lot of luck with flux. Hovering around 180 still as was mentioned. Everything seems to have settled back for the moment. 
It will pick up eventually.

N.

 

Yeah, true. Also in some past cases it is possible, perhaps even likely that those observations were done after periods of flaring etc. The Maximum useable frequency is really the maker or breaker when it comes to Dx.  

[Newbie]

3 minutes ago, hamateur 1953 said:

Yeah, true. Also in some past cases it is possible, perhaps even likely that those observations were done after periods of flaring etc. The Maximum useable frequency is really the maker or breaker when it comes to Dx.  

Well you need flux to increase a little and Kp to stay lowish for a few days. MUF should increase 😊

N.

[Genie]

5 minutes ago, Newbie said:

Well you need flux to increase a little and Kp to stay lowish for a few days. MUF should increase 😊

N.

I think you are correct here. but i don't know why. can you elaborate?

[Newbie]

2 minutes ago, Genie said:

I think you are correct here. but i don't know why. can 

 

Here is a link to the information I posted a little while back.

The solar flux is closely related to the amount of ionization and hence the electron concentration in the F2 region.

K values between 0 and 1 represent quiet magnetic conditions and this would indicate good HF band conditions, subject to a sufficient level of solar flux.

N.

[Sunshine]

I never would have guessed I'd learn about hamradio, but thanks to you dedicated and friendly lot, I once again learned something new. Good luck for your endeavours to our HAM operators! 

[hamateur 1953]

Thanks @Sunshine. Wow. From our entire community. From me personally as well. Having been accused of contacting Mars ( jk). And generally viewed as eccentric ( true). Haha. Outta likes again doggone it. Catch ya later. 73. ( best regards). Mike/ Hagrid

our FCC won’t licence him. Don’t worry. 

1 hour ago, Sunshine said:

I never would have guessed I'd learn about hamradio, but thanks to you dedicated and friendly lot, I once again learned something new. Good luck for your endeavours to our HAM operators! 

[hamateur 1953]

http://www.ham-radio.com/n6ca/50MHz/K6MIO_50MHz_F2Prop.pdf

I thought I had included this excellent PDF.  But hadn’t It is very comprehensive but clear in its explanations.  Its old but I doubt our ionospheric behaviour has changed much. Haha. 

Edited February 17 by hamateur 1953

[Philalethes]

4 hours ago, hamateur 1953 said:

http://www.ham-radio.com/n6ca/50MHz/K6MIO_50MHz_F2Prop.pdf

I thought I had included this excellent PDF.  But hadn’t It is very comprehensive but clear in its explanations.  Its old but I doubt our ionospheric behaviour has changed much. Haha. 

I was wondering about something that you might perhaps clear up for me: in that document it mentions how daytime D layer activity strongly absorbs frequencies of 10 MHz and below, and in this article I came across it mentions how the 80-meter band can experience as much as 25 dB of absorption; the latter corresponds to a frequency of ~3.75 MHz, but I can't see how that amount of absorption matches up with the D-RAP model we discussed in the other thread, where frequencies of 3-4 MHz show only ~5-10 dB of absorption during normal X-ray background periods, and frequencies between 5-10 MHz seem to only show ~1-5 dB of absorption. What is the reason for this apparent discrepancy?

[hamateur 1953]

15 hours ago, Philalethes said:

I was wondering about something that you might perhaps clear up for me: in that document it mentions how daytime D layer activity strongly absorbs frequencies of 10 MHz and below, and in this article I came across it mentions how the 80-meter band can experience as much as 25 dB of absorption; the latter corresponds to a frequency of ~3.75 MHz, but I can't see how that amount of absorption matches up with the D-RAP model we discussed in the other thread, where frequencies of 3-4 MHz show only ~5-10 dB of absorption during normal X-ray background periods, and frequencies between 5-10 MHz seem to only show ~1-5 dB of absorption. What is the reason for this apparent discrepancy?

@Philalethes Point well taken.  The D-RAP model is now also incorporating particle absorption as well, And these are of course estimated path loss during periods of sunlight.  What also isn’t shown are the background noises ( lightning, local emf from electrical and electronic devices)  The D-RAP was I believe originally intended for use by high-power international broadcasters who had the abilities to “ steer” their emissions using different directions of transmission, hence it probably wasn’t intended for in depth study either. Although I actually think it may respond coincidentally to long Gamma Ray bursts greater than two seconds. 
Above approximately 10 mhz under normal conditions the D layer is practically transparent to radio waves. 
Why this is, I couldn’t really say. Other than our time station WWV in Fort Collins Colorado can be heard anywhere day or night on 10 mhz usually within our National borders.   For a simplification: The higher in frequency the signal, the less exposure to the elements are present, hence less absorption or diffusion.  Hopefully this clarifies a difficult subject.  Mike/ Hagrid.   PS. @KW2P did an excellent thing called Basics of Shortwave Propagation in this section for anyone else interested in the above subject matter.  I might add that computer models are created by human beings and two models of the same events are unlikely to agree.  Mike. 

Edited February 18 by hamateur 1953
Clarity I hope and grammar Haha. Tagged author

[hamateur 1953]

One more afterthought, if you notice the D-RAP model run during periods of SFI below about 110 you likely won’t see much at all. Only black with the sun track following its normal path.  There remains large attenuation or normal reduction in signal loss that is always present in our D layer.  Think of it as a protective blanket from nasty stuff and you will be pretty close.  At solar minimum or around 70 SFI it still does its job quite effectively indeed.  

[Philalethes]

On 2/18/2024 at 1:37 AM, hamateur 1953 said:

One more afterthought, if you notice the D-RAP model run during periods of SFI below about 110 you likely won’t see much at all. Only black with the sun track following its normal path.  There remains large attenuation or normal reduction in signal loss that is always present in our D layer.  Think of it as a protective blanket from nasty stuff and you will be pretty close.  At solar minimum or around 70 SFI it still does its job quite effectively indeed.  

Yeah, that really clarifies what I gleaned from your answer above, i.e. that the D-RAP model essentially models what the additional loss due to the X-ray and/or proton flux is, and doesn't say anything about the attenuation that is always present in varying degrees otherwise.

[hamateur 1953]

On 11/26/2023 at 1:29 PM, Newbie said:

 

Unfortunately you are not having a lot of luck with flux. Hovering around 180 still as was mentioned. Everything seems to have settled back for the moment. 
It will pick up eventually.

N.

 

Yes we are in what others have referred to as a sawtooth climb. Periods of heightened activity interspersed with drops across the board in flux and overall activity. This isn’t entirely due to one side of the sun being more active or particular longitudes  being hot although this is important as is hemispheric activity. 
Today I observed on our 50 mhz band a truly remarkable situation that looked more like F2 than Es layer reflection.  Region GG in South America ( Argentina I think) was making contacts into region DO in Canadian provinces. On 28 mhz no big deal of course but quite a contact for whoever was in Saskatchewan and Alberta on six metres. SFI under 170 also.   Approximately 6,800 miles or around 11,000 km.  Pretty awesome DX for those guys! Whatever layers were involved.  Noteworthy is the fact that overall flux was well into the C range most of the day, likely due to region 3615 which is on the west limb presently.    @Philalethes noted this fact about a month ago during another Es event.   One more interesting fact. I also noted transpacific 50 mhz into New Caledonia ( north of NZ) and another small land mass I don’t recognize adjacent to it from Southern California! These were noted At about 23:00 utc March 30 2024. 

Edited March 30 by hamateur 1953
Distance. And Mid C level flux

[helios]

I was never much of a 6m person, only tried it once for meteorscatter, years ago.
But in the past days I was a lot on 6m and was surprised that it works almost every day to south africa from central europe.
I also think that spradic-E was not involved. But perhaps transequatorial propagation is particularly efficient around the equinox?

[Philalethes]

7 hours ago, hamateur 1953 said:

Yes we are in what others have referred to as a sawtooth climb. Periods of heightened activity interspersed with drops across the board in flux and overall activity. This isn’t entirely due to one side of the sun being more active or particular longitudes  being hot although this is important as is hemispheric activity. 
Today I observed on our 50 mhz band a truly remarkable situation that looked more like F2 than Es layer reflection.  Region GG in South America ( Argentina I think) was making contacts into region DO in Canadian provinces. On 28 mhz no big deal of course but quite a contact for whoever was in Saskatchewan and Alberta on six metres. SFI under 170 also.   Approximately 6,800 miles or around 11,000 km.  Pretty awesome DX for those guys! Whatever layers were involved.  Noteworthy is the fact that overall flux was well into the C range most of the day, likely due to region 3615 which is on the west limb presently.    @Philalethes noted this fact about a month ago during another Es event.   One more interesting fact. I also noted transpacific 50 mhz into New Caledonia ( north of NZ) and another small land mass I don’t recognize adjacent to it from Southern California! These were noted At about 23:00 utc March 30 2024. 

The X-ray flux has been consistently very high lately, so I'm guessing that's part of the cause. I believe you and other amateur radio enthusiasts explained some time ago that the F2-layer responds fairly slowly and needs higher flux for longer periods of time to ionize properly, so maybe that's why you're seeing that after this period of prolonged high flux from 3615. At some points it almost seemed like the background flux was M1+, and the 24-hour average flux was well into the M-range on several occasions. I see it was reflected in the F10.7 as well with another day well above 200 and hovering around there for multiple days too.

[hamateur 1953]

11 hours ago, helios said:

I was never much of a 6m person, only tried it once for meteorscatter, years ago.
But in the past days I was a lot on 6m and was surprised that it works almost every day to south africa from central europe.
I also think that spradic-E was not involved. But perhaps transequatorial propagation is particularly efficient around the equinox?

I never was either.  Mainly 10 and 160. Both ends. Haha.  Lots of time on 2 and 70 cm ( 440 mhz)  But it isn’t called the magic band for no reason.  All forms of propagation are present there.  Es was easy south in summer!  I think your supposition is correct.  Particularly in view of the gif you posted earlier.  73. Mike 

11 hours ago, Philalethes said:

The X-ray flux has been consistently very high lately, so I'm guessing that's part of the cause. I believe you and other amateur radio enthusiasts explained some time ago that the F2-layer responds fairly slowly and needs higher flux for longer periods of time to ionize properly, so maybe that's why you're seeing that after this period of prolonged high flux from 3615. At some points it almost seemed like the background flux was M1+, and the 24-hour average flux was well into the M-range on several occasions. I see it was reflected in the F10.7 as well with another day well above 200 and hovering around there for multiple days too.

I think this is a distinct possibility although 10,000 km is really unusual traditionally Es on 50 mhz is about 1500 mile maybe a bit longer.  F2 allegedly about 2,500. But in reality we only speculate as to the method using geometry and relative heights.  The really interesting thing to me was that the MUF over that path by digisonde was under 40 mhz. (37).  But there are only a few in the states. Austin tx idaho falls vandenberg ca and a couple more on the east coast. These use vertical incidence as Im sure Helios knows to calculate approximate MUF.  Double hop es or quadruple hop?  Haha. @helios @Philalethes @KW2P  Again today with sfi at around 140 and Muf over the entire distance no higher than 37mhz I see that N6KK is working FK8CP, ZL3OZ over what must be double or triple hop Es into New Zealand all on 50mhz. Also a maritime mobile near Taiwan is working ZL3OZ.  The FK8CP callsign rings a bell though I haven’t worked him before. Looks as though there may be something to this after all.  Very short distance 50 mhz contacts in the states.  May mean 2 metres a possibility on Es.  This began shortly after the near X flare from 3615.  Nothing in my grid square naturally haha.  Mike 

Edited March 31 by hamateur 1953
Update

[KW2P]

Did my own MUF measurement a few days ago. Condx were very strange -- blackout on the low bands so high radiation. Was tuning around on the 10m band and came across two strong signals. (Morse code) One of them sounded rather weird so I listened. Checked the callsign and it was a ham 28 miles north of me(!) I called him and we exchanged information. (I'm in Clarksburg, he was in Morgantown, WV)

As I listened I realized what was going on and why it sounded weird. There was reverberation / ringing from our signals bouncing multiple times between the F-layer and the ground, which would result in "reverb" with a peak at around 500 Hz.  The conditions lasted only a few minutes and then he faded out.

Afterwards we connected on the Internet. He thought our highly unusual contact was groundwave. But I explained to him that it was definitely not groundwave. Groundwaves at 28 MHz collapse flat to the ground very quickly, a mile at most. No, we were using the F-layer. What's more, were it groundwave, it would been stable, not faded, and no reverb.

Anyway, at that moment, the MUF was above 28 MHz here. Haha.

 

[hamateur 1953]

6 hours ago, KW2P said:

Did my own MUF measurement a few days ago. Condx were very strange -- blackout on the low bands so high radiation. Was tuning around on the 10m band and came across two strong signals. (Morse code) One of them sounded rather weird so I listened. Checked the callsign and it was a ham 28 miles north of me(!) I called him and we exchanged information. (I'm in Clarksburg, he was in Morgantown, WV)

As I listened I realized what was going on and why it sounded weird. There was reverberation / ringing from our signals bouncing multiple times between the F-layer and the ground, which would result in "reverb" with a peak at around 500 Hz.  The conditions lasted only a few minutes and then he faded out.

Afterwards we connected on the Internet. He thought our highly unusual contact was groundwave. But I explained to him that it was definitely not groundwave. Groundwaves at 28 MHz collapse flat to the ground very quickly, a mile at most. No, we were using the F-layer. What's more, were it groundwave, it would been stable, not faded, and no reverb.

Anyway, at that moment, the MUF was above 28 MHz here. Haha.

 

Wow!!! That is incredible!!   Long-delayed reverb. Haha..   For fun I assumed your Fo was 28 mhz and came up with 144 mhz as muf and about 1,500 miles as a possibility using the online calculator. Two meters may have been open for Es for a brief time anyway!  Haha. 

Edited March 31 by hamateur 1953

[helios]

There are indeed many interesting propagation modes. But sometimes it's difficult to explain what actually happens.

One of these modes is sidescatter. A reflection not on the direct path, but to the side of both stations.
Gwyn G3ZIL explained in his presentation how these modes can be analyzed with digital modes: https://www.youtube.com/live/zBE8lTyfQdY?si=ASMoGxHhk_etfcjg&t=237

And another mode is aircraft scatter, particularly on the upper HF bands and VHF. I can often observe it on 10m. I live in the Alps, which means, normally I can't hear the stations in the Valley next to me, because there are big mountains in between. But when an Airplane flies above us, we can hear each other for a few minutes. Including slight doppler drift.

 

 

[hamateur 1953]

28 minutes ago, helios said:

There are indeed many interesting propagation modes. But sometimes it's difficult to explain what actually happens.

One of these modes is sidescatter. A reflection not on the direct path, but to the side of both stations.
Gwyn G3ZIL explained in his presentation how these modes can be analyzed with digital modes: https://www.youtube.com/live/zBE8lTyfQdY?si=ASMoGxHhk_etfcjg&t=237

And another mode is aircraft scatter, particularly on the upper HF bands and VHF. I can often observe it on 10m. I live in the Alps, which means, normally I can't hear the stations in the Valley next to me, because there are big mountains in between. But when an Airplane flies above us, we can hear each other for a few minutes. Including slight doppler drift.

 

 

That’s pretty amazing @helios  I live directly under the flight path where planes typically decelerate and then bank towards Sea-Tac airport and used to have a minute or two when I would hear another two metre repeater in Vancouver 100 miles north also. Haha. I am definitely going to get that six metre ground plane up tomorrow as the Es season appears to be on us again   I still have a mess of QSL cards if I make history this cycle   It was fun years ago to receive cards from rare DX   SSB or CW are my preferences   FT-8 is cool for weak signal work but I miss the thrill of the chase if you get my drift   Mike

 

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