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Groundwave Reception

That's unheard of as far as I know.

On an individual frequency, there might be a brief few seconds at a time from time to time where a skywave signal is absent or seems to be but never a consistent thing.
 
Yes, under auroral conditions. Auroras silence the skywave signals... and, interestingly, you may even pick up lower-powered distant stations via groundwave. My most distant catch came that way: WPCF in Panama City Beach, Florida from Horton, Michigan during an aurora in 2004.
 
It can happen when solar activity is very high. AM at night can virtually look like the daytime band, except for a few powerhouse stations.
Also, if you're far north, in some situations less drastic than the above, signals can just disappear. From northeast Oregon, I've seen normally local-quality KVI-580 Seattle totally absent but all other stations normal.
 
Auroral conditions can take out all the skywave signals, leaving the band sounding like daytime except with everyone being on night power/pattern. It can also knock out northern signals, and if you combine that with good skip from the south, it can be DX gold (with lots of Spanish)
 
I've heard greatly diminished skywave activity at night but never completely absent all across the band.
 
Mario, i am in Fresno (36th parallel lat.) and I can say that occasionally aural conditions can come down this far south. Not often, but maybe averaging about a couple days per year. But that could be 4 days one year and none the next three years.
I'm in California, Sacramento, Vallejo

So I don't know about Auroras down here
 
I've mentioned this before but about 30 years ago, I was in Tok Alaska at night in October and there wasn't a hint of a station across the entire AM band! I'd always wondered why and now I know. Thank you.
 
Skywave only happens when the lower layers in the ionosphere disappears after the sun goes down and stops ionizing the atmosphere.....then the upper layers start reflecting the signals back to earth as skywave (which is why MW can never be heard on the moon....wont make it out that far....SW and TV will.........and even SW has a fight to get out of the atmosphere!!) During eclipses, skywave shows up in the middle of the day......and when a solar storm happens, night time skywave goes away......all due to the ion charges in the upper layers........due to scienece, can be easily explained now...but imagine when radio was in its infancy and it was all magic then!! :)
 
I should add that the visibility of an aurora will indicate a strong effect on signals. In that 2004 event I mentioned earlier, there was a very bright light show going on in the sky -- mostly green, which is more than we usually see at my latitude, but even some yellows, reds and purples -- and the vast majority of the AM band was dead silent. Not even the usual background noise. In fact, the only static was coming from the charged particles hitting the ionosphere. I could easily correlate the strength of the visible aurora with the frequency of static bursts on the radio. I haven't experienced that strong an effect before or since.
 
Mentioned in an older thead was the possibility of avenues, or passages, from one region to another taking on directional properties due (maybe) to terrain and, possibly, frequency, Mario.
@$$uming that has some validity :)- ) , then why not the same scattershot conditions afoot during one of those ghostly and varying veils of an Aurora? And from what I've been told, the Aurora itself doesn't have to be visible to affect matters.

I'm equidistant from Hazleton and Pottsville PA. On nights when both WAZL 1490 and the farther-south WPAM 1450 are loud and clarion, the Great Northern Lights are influencing reception. Usually those two stations are atop the frequency anyway, but both their coverage areas they come equipped with a notable nighttime grumble from some others on the channel. Sometimes both WAZL and WPAM will even fade under another station for a while. My understanding is that on those rare occasions I'm getting their ground wave as though it were daylight out.

Back on Long Island I got my coolest catch ever during an Auroral overnight. The barometer was another graveyarder -- WFAS 1230 from White Plains. The distance between them and our crew with the hungry loops down by JFK Airport was 25 miles. That's usually plenty of space for stations such as WFAS to get good and mangled.
But WFAS was crystal that overnight. So was neighboring semi-local WGBB from Freeport.
Uh-oh.
Aurora time.
Get out the Spanish dictionary or the old textbooks.
The other four GY channels were a delightful, almost inaudible mess of Spanish. The only one I IDed was HJAS 1400 from Colombia '' Roddio Univers - SOLL'.

Perhaps the engineering folks can fill us in on whether or not the signals we get from those those big northern latitude stations on huge Aurora nights ..... WGN Chicago, WGY Schenectady, WWKBW Buffalo ..... are from some manner of default groundwave at night.

Lol Semoochie : My pal had a great Yogi-Berra line about DXing one night. There were three of us, from the old Long Island crew, testing out the new GE Superadio II they had just bought me as a birthday gift.
The town where I lived was in a hole. The only FM stations he got comfortably were the huge T-102 and WMGH 105.5 Tamaqua.
Vinny, his eyes wild with glee, said, 'What a great place to DX! Nothing comes in!'
 
And from what I've been told, the Aurora itself doesn't have to be visible to affect matters.
Just to clarify my point, I wasn't saying that the aurora had to be visible to affect signals. I was simply saying that if the aurora is visible, the effect it has on radio signals tends to be stronger. Most common here in my part of Michigan are the weaker, quick bursts of solar discharge -- the kind that you can only see if you're not looking directly at them and can occasionally hear fizzle as they hit the atmosphere. Those cause bursts of static on the radio, but don't generally silence the whole band. If you get steady waves of weak discharge instead of bursts, it can start to cause some silencing. The more visible the aurora is, the stronger the effect it has. That was what I was saying.
 
Oh hey, Josh ..... I wasn't implying or nitpicking. Heck -- you've probably seen and heard ten times the Auroral effect there in Michigan than I'll ever know here, anyway!

I was merely explaining to Mario -- and maybe he knows this already -- that even if he can't see it where he lives, when the Great Auroral Pumpkin visits the lower 48 states, it already has done its blanketing duties on the stations north of him.

* * * * * * *

Birthday boy here got another nice, serendipitous gift a few Octobers ago. We were driving home from a party the in-laws threw for me, near Elysburg PA. There's a wee airport right behind their house, for private planes, and hardly any lights, and this road follows the runway for a nice open stretch. For some reason the street is named 'Airport Rd'.
Happy Birthday, Steve! Here's an Aurora for you!
I had to to a upie and drive back, fetch the in-laws, and we all then drove around for :45 minutes or so, watching this unexpected nightcap to the gaiety of the evening. Oddly, I didn't turn on the car radio once.
And when her Mom said, 'Okay, this is nice, but it's getting late,' Linda says that as soon as we go to drive them home, a big lightning bolt was going to come out of the sky.
'Well, okay. Maybe we'll stay and watch a little while longer.'
 
One of the propagation websites mentions that the 'radio aurora zone' goes farther south than the optical aurora zone, i.e. the area where you actually see an aurora.

Their Near Real Time MUF map shows the 'radio aurora zone', which lies in between the green lines on the map.

I suspect that the actual effects of an aurora on the MW extends even further south than the 'radio aurora zone' as shown on the map. The last time we had auroral conditions here in WA the MUF map showed the green colored 'radio aurora zone' a couple states away.

http://www.spacew.com/www/realtime.php
 
One of the propagation websites mentions that the 'radio aurora zone' goes farther south than the optical aurora zone, i.e. the area where you actually see an aurora.

Their Near Real Time MUF map shows the 'radio aurora zone', which lies in between the green lines on the map.

I suspect that the actual effects of an aurora on the MW extends even further south than the 'radio aurora zone' as shown on the map. The last time we had auroral conditions here in WA the MUF map showed the green colored 'radio aurora zone' a couple states away.

http://www.spacew.com/www/realtime.php

I usually can get an answer from Lisa Kelly - I will ask her about skywave vs. auroral activity on AM on the ice roads. She has already told me there is little or no skywave reception that far north.
 
The first time I actually saw an aurora, over Platte Bay, Lake Michigan, I also tried the car radio, and heard XEX clearly with no trace of the usual CKAC.

One night, I was watching with TV my in-laws, when an ad mentioned the Grand Ole Opry. My MIL reminisced "remember when we could hear the Grand Ole Opry on the radio?". Of course, at this point I found a radio and attempted to show her she still could (this was years before IBOC). To my surprise, no WSM, only a 650 in Colombia!

The odd thing about AM BCB DX is that some of the best DX is heard because conditions are lousy!
 
The odd thing about AM BCB DX is that some of the best DX is heard because conditions are lousy!

I recall a time in the early 60's when a family member who was about 25 miles north of Traverse City called to tell my mother that the aurora was visible over Grand Traverse Bay. I was hundreds of miles to the southeast in Cleveland and could not see the lights. But I turned on my radio and pulled in more than a dozen new Venezuelan stations. The best was a 5 kw station on 1100... unusual because I was only about 20 miles from Cleveland's 1-A clear channel on 1100 yet the Venezuelan was overriding it. Second best was a 1 kw station on 1370 from Valle de Pascua, Venezuela... on Venezuela's inland plain in the southern part of that nation.
 
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