HamSCI Eclipse & Gray-Line Propagation

[Chris Cote]

I wonder if we are going to see a Gray-Line propagation effect?

--

Chris Cote

KE5NJ

President

Kent Amateur Radio Society

[Jeffrey Carroll]

Is that due to the Equatorial Ionospheric Anomaly? 

--
Please follow the HamSCI Community Participation Guidelines at http://hamsci.org/hamsci-community-participation-guidelines.
---
You received this message because you are subscribed to the Google Groups "HamSCI" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hamsci+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CABWNEteKejj%3DMwJzKtsKEM6cK0U7ic-Yv4r2zBDAc8VE4Yq4gg%40mail.gmail.com.

[Chris Cote]

http://g0kya.blogspot.com/2009/01/greyline-propagation.html

This explains what Gray-Line propagation is.

Chris Cote

KE5NJ

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CAJE8dbuUgQ8zvXjeN3uM7y2gPb9ojQW2PXpede2n_JFMjXs9jw%40mail.gmail.com.

[Chris Cote]

https://rsgb.org/main/technical/propagation/greyline-around-the-world-propagation/

Chris Cote

KE5NJ

On Wed, Oct 4, 2023 at 5:46 AM Jeffrey Carroll <jeffrey.c...@gmail.com> wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CAJE8dbuUgQ8zvXjeN3uM7y2gPb9ojQW2PXpede2n_JFMjXs9jw%40mail.gmail.com.

[Chris Cote]

On Wed, Oct 4, 2023 at 5:46 AM Jeffrey Carroll <jeffrey.c...@gmail.com> wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CAJE8dbuUgQ8zvXjeN3uM7y2gPb9ojQW2PXpede2n_JFMjXs9jw%40mail.gmail.com.

[Chris Cote]

For those who have net heard of Gray Line propagation, here is a good article about it...attached.

Chris Cote

KE5NJ

[Dr. Nathaniel A. Frissell Ph.D.]

Hi,

 

I think these are good questions. As you know, the greyline is enhanced propagation associated with paths along the dawn/dusk region. I’m not entirely sure how you would compare the propagation around the circular eclipse shadow with that greyline propagation along a long, linear path. Still, there may be some way to make useful comparisons and test some of our understanding of greyline. A useful and recent reference to start with when studying greyline is the Lo et al. (2022) study: https://doi.org/10.3390/atmos13081340

 

The equatorial ionospheric anomaly are enhanced regions of ionization just north and south of the geomagnetic equator due to something called the fountain effect. See https://doi.org/10.26464/epp2018025. While traversing North America, the eclipse will not be close to the EIA and will likely not be affected by it. However, towards the end of the eclipse the shadow will be over South America and will go in/near the EIA. Early model runs by Joe Huba suggest that the eclipse going through the EIA may produce ionospheric bubbles/irregularities that would not otherwise be there. But, more modeling and observational testing need to occur.

 

73 Nathaniel W2NAF

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CABWNEtf5cFGFPkmQxUyQ-Tg0S_aucdR_L9wFnMNkH1N2ZuYe%2Bg%40mail.gmail.com.

[Ward Silver]

The phenomena (plural) associated with "grey line" propagation involve a number of mechanisms that vary with frequency.  What happens on the lower HF bands is quite different than what happens on the higher bands.  K9LA sorts some of this out in a good WWROF presentation:

https://www.youtube.com/watch?v=gFypM023O-I&ab_channel=WWROF

It's safe to say that interesting things happen around sunrise and sunset but they aren't all the same thing. The most important common element is to be on the air to experience whatever occurs.

73, Ward N0AX

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/MW5PR03MB7005FA8119B9DFC2533CE4A8F2CBA%40MW5PR03MB7005.namprd03.prod.outlook.com.

[Robert McGwier]

I agree about being active and observing.

HAMSCI got people on the air during the major cross country eclipse a few years ago and the one for sure finding is almost all prognosticated outcomes did not happen. 40 meters was much better and quite long during and right after totality. The major changes are much stronger in amplitude than anticipated. 

Get in the air.

Bob

N4HY

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CAFr7d%3DoeEu4xBCvg_Ys2_w%2BCp2yag71vN%3DoxbUD7g%3DGngs9GPA%40mail.gmail.com.

[Ron KF7ZN]

As I have been following this thread I remembered that  Dr Skov has some good slides about grey line/region that some will find very helpful

https://www.youtube.com/watch?v=SoXXEIetg4k&list=PPSV

start at 1:19:00 to 1:32:00 and 1:36:00 to 1:39:00

Have a nice day!

Ron Wilcox KF7ZN

RN, BHS, BSN, CCM

Ham Radio Volunteer Examiner

Vice President Utah DX Association

HamSCI

To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci/CA%2BK5gzf3%3DvrMm6DZf%3DM2J%3DKi3oB%2B_tM-ABBPqOL5Ro%2BuaeFBdg%40mail.gmail.com.