The AM Forum

Band Watch => 80/75 Meters => Topic started by: Tom WA3KLR on September 13, 2023, 12:12:33 PM



Title: 9/13 Black-out
Post by: Tom WA3KLR on September 13, 2023, 12:12:33 PM
I haven't heard a signal on 75 for an hour now. SF = 154, A = 25, K =3. I haven't checked any other bands yet.

 - - - - - - -

12:19 p.m. I hear signals on 40 meters and WWV is coming in on 10, 15, 20, and 25 MHz.


Title: Re: 9/13 Black-out
Post by: AJ1G on September 13, 2023, 05:03:09 PM
What time did you actually post this Tom?  The forum says just after
noon, but not sure what time zone the forum is time tied to.  If it was just after noon EDT, band is almost always all being sucked up by the D layer every day.  After about 9 AM I can’t hear much of my signal on 75
on any of the usual SDRs in the Northeast.



Title: Re: 9/13 Black-out
Post by: Tom WA3KLR on September 13, 2023, 06:55:03 PM
Hi Chris,

I posted at 12:12 p.m. I was on an AWA net 9:30 to 10:30 a.m. and by 11:00 no signals seen on the band. Yes partly due to people abandoning 75 during the day, but NO signals at all until after 3.p.m. I'll have to observe the band tomorrow for "normal" 11 a.m. to 3 p.m. behavior.


Title: Re: 9/13 Black-out
Post by: W3SLK on September 13, 2023, 07:19:27 PM
Looks like there was some geomagnetic activity yesterday.(https://services.swpc.noaa.gov/images/swx-overview-small.gif?time=1694646976000)


Title: Re: 9/13 Black-out
Post by: Tom WA3KLR on September 13, 2023, 08:42:37 PM
Thanks for the graphs Mike. I'm quite familiar with the D layer absorption in the daytime, especially summer. I don't consider an A index of 25 normal though. I put my laptop on the K3FEF SDR and I could barely hear myself at 65 miles from the receiver. Anyhow, winter is coming!


Title: Re: 9/13 Black-out
Post by: W3SLK on September 14, 2023, 10:43:48 AM
Tom, that was from NOAA weather page. They now have a specific page dedicated the ionosphere and geomagnetic activity: https://www.swpc.noaa.gov/communities/radio-communications


Title: Re: 9/13 Black-out
Post by: Tom WA3KLR on September 14, 2023, 01:30:24 PM
Yesterday         SF = 154, A = 25, K =3
Now 1:24 p.m. SF = 143, A = 17, K =1. Better. I've seen a couple of tune'er up'ers, but no real activity.


Title: Re: 9/13 Black-out
Post by: Tom WA3KLR on September 20, 2023, 03:40:55 PM
During the Bruce Kelley Antique Wireless Association net this morning on 3837 kHz the band blacked out at 10:17 a.m. A index = 49 now. I do see some activity.

The propagation website I look at, now has its 3000 km. global MUF map back in service after a few years of absence:

https://dx.qsl.net/propagation/index.html

Like the previous 75 Meter black-out, I could hear WWV on 10 through 25 MHz.
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