Questions about Daytime Skywave Skip

[Steve Green NEPA]

I know that after looking at this weather map I should be a few inches away from an AM radio dial doing my curious best to give weight toa vague theory.
But the AM dials -- all of them in town -- are too noisy.

The Weather Channel Maps | weather.com

weather.com

Note that 'fall line' arc along the Appalachian as of 4:30PM ET.
Now, I've received several neat daytime skywave skip stations, both here landlocked PA and back in water-path-enhanced Queens NY, near JFK -- real unlikely stuff both from the NE and the SW along such a front.
Main question (from a guy who flunked both Physics 1 and Physics 2 in HS and had to take both over in the last term) : Are AM reception abnormalities due to much the same reasons as FM oddities during times of temperature 'inversions' or other such extremes?
Thank you for your attention,
M. Kameny, ret then un-ret'd
Brooklyn Tech Physics Dep't

 

[DavidEduardo]

Are AM reception abnormalities due to much the same reasons as FM oddities during times of temperature 'inversions' or other such extremes?

It was always explained to me as unusual ionospheric occurrences related to things like sunspots and the like. For example, in recent days many AM DXers noted almost total night skip reception as if the ionosphere had not "activated" for several nights in a row. Explanations had to do with solar storms.

I am not a scientist or a physicist so this is pass-along information I picked up from those who knew a lot more about this.

 

[gar hi]

I've always thought AM skywave reception had nothing to do with weather conditions because the skip is caused by layers of the atmosphere so much farther up.

Shortwave reception has been lousy the past couple days too.

 

[DavidEduardo]

I've always thought AM skywave reception had nothing to do with weather conditions because the skip is caused by layers of the atmosphere so much farther up.

That's my impression, too.

What confuses the situation is that a lot of AM DX depends on lower noise levels, and those definitely can be raised by low level storms, lightening and the like.

 

[gr8oldies]

AM (Medium Wave) enhanced daytime reception would have nothing to do with surface weather conditions (with the exception of lightning crashes). Sometimes in winter, the ionosphere doesn't fully deactivate, and some measure of skip can hang in all day. That was also noticeable due to the 2017 eclipse in areas of totality. Daytime skip is my favorite DX.

 

[CTListener]

My understanding is that cloud cover has no effect on radio reception at all unless there's electrical activity taking place in the clouds, and even then, that's no factor on FM. I've never noticed any degradation of reception of SiriusXM satellite radio on cloudy days, but I've read that satellite TV reception is affected by clouds. Is that true, and if so, why?

 

[semoochie]

During the total eclipse on February 26, 1979(my mother's birthday), I tuned across the dial and found that nighttime reception had returned. It was only a short time after sunrise, so I don't know whether or not that entered into the equation.

 

[gr8oldies]

During the total eclipse on February 26, 1979(my mother's birthday), I tuned across the dial and found that nighttime reception had returned. It was only a short time after sunrise, so I don't know whether or not that entered into the equation.

I don't remember that one. Where were you located? The one I experienced in August 2017 in East Tennessee did have night-time-like reception but it was happening west-to-east, with the first station noted being KXEL.

 

[jim-satx]

During the total eclipse on February 26, 1979(my mother's birthday), I tuned across the dial and found that nighttime reception had returned. It was only a short time after sunrise, so I don't know whether or not that entered into the equation.

I’m looking forward to this on April 8 of next year when a total eclipse will be visible in northwest San Antonio around 1:30 p.m.

On October 14 of this year, an annular eclipse will be visible here around noon. I wonder if the ionosphere will be partially activated during the height of it.

 

[gr8oldies]

I’m looking forward to this on April 8 of next year when a total eclipse will be visible in northwest San Antonio around 1:30 p.m.

On October 14 of this year, an annular eclipse will be visible here around noon. I wonder if the ionosphere will be partially activated during the height of it.

I'll be in Mena, Arkansas for the April 8 eclipse. We're having a family reunion around it.

 

[formula72]

Strange!
I have experienced days/nights were FM signal reception tended to be great. I'm not sure what causes it, but certain times, I can pick up radio stations over 160 miles away, and then the next day/night, they are gone. It's a very sporadic event.
I remember back in the 1990s, when I had a small radio shack 5" B&W TV, Sometime I would receive (and watchable) KTXL TV-40 out of Sacramento on the UHF band off the dipole antenna. Then, within hours, it was gone (nothing but static).
What causes these strange events...?

 

[Gregg.]

And where were you when you caught KTXL TV 40 Sacramento?

 

[Mark Roberts]

I don't remember that one. Where were you located? The one I experienced in August 2017 in East Tennessee did have night-time-like reception but it was happening west-to-east, with the first station noted being KXEL.

For the 2017 eclipse I was visiting Columbia, Missouri, a city I know well. I noticed no unusual activity on the AM band before totality; after totality was an entirely different story. For me, reception was east-to-west, with stations from roughly 400-500 miles away predominating. It took about an hour for the enhanced reception to go away altogether. I tried to record some of this but my digital recorder created some kind of interaction with the DSP-based receiver I was using. I had to shut off the recorder as a result.

There was a partial solar eclipse in 1994. I was living in Kansas City then. I noticed reception enhancement for that eclipse as well, though the effects were less dramatic. For example, I could receive AM stations from southwest Missouri that normally were not received in Kansas City. At the time, I wrote this up for a post in rec.radio.broadcasting - I'll have to see if I can find it. I also had a correspondence going with a retired EE professor in Buffalo (I think it was) who noticed similar phenomena in that area during the partial eclipse.

Don't forget the annular eclipse this October, too! There's a good chance I'll be in New Mexico for that one, either in the Four Corners area (to get away from the Albuquerque Balloon Festival) or in Albuquerque itself.

 

[Mark Roberts]

It was always explained to me as unusual ionospheric occurrences related to things like sunspots and the like. For example, in recent days many AM DXers noted almost total night skip reception as if the ionosphere had not "activated" for several nights in a row. Explanations had to do with solar storms.

I am not a scientist or a physicist so this is pass-along information I picked up from those who knew a lot more about this.

Northern lights will desensitize the ionosphere for AM stations at more northerly latitudes. This can present a good opportunity to catch stations to one's south, especially from the Caribbean or Mexico...even if the Northern lights are not visible in your area. In my Midwestern days, when Northern lights were present farther north of my Kansas City location, reception from Minneapolis or Chicago would be totally wiped out and the Cuban stations especially would come roaring in.

 

[Mark Roberts]

Here was what I wrote in 1994 about the partial solar eclipse. I was in Kansas City at the time.

I took a long lunch today (May 10), drove home, and listened to the solar eclipse.
Observations of the eclipse's effect on the radio dial in south-central Kansas City:
* KFRM (550, Salina, Kansas) could be received in the car without any interference from KSD St. Louis at 11.30 am. The signal was not terribly strong, but the lack of interference was unusual.
* KFDI (1070, Wichita, Kansas) registered a two (on a scale of five) on my home tuner's signal strength indicator at 11.45 am (the peak of the eclipse). Half an hour later, it was back at zero though still barely audible.
* KFSB (1310, Joplin, Missouri) registered a three at about 11.55 am. Normally, I do not receive this station. It appeared to be
simulcasting its FM station, which is a real comedown for one of southwest Missouri's high-coverage signals.
* KKLL (1100, Webb City, Missouri) registered a two on the tuner at about the same time. I didn't listen for long; I can normally get it only in the car; normally, it runs a format (Christian easy-listening) that is quite avoidable.
* Traces of KGBX [I should have written KTTS] (1260, Springfield, Missouri) were heard at around 12 noon. Normally, it doesn't make it up here at all. I didn't try KWTO at 560; it usually comes in up here OK.
* While on the way home in the car, I listened to the station at 1530 in Butler, Missouri (KMAM). This small-town station had enough creativity to drag a microphone or two out to its parking lot and have its DJs describe what they were seeing and talk to people driving up, asking what they thought of the eclipse and what they were seeing. Little KMAM was doing a better job of being an on-the-spot radio station than the big-city (and not-so-big-city) talk stations relaying the bloated blathering of Rush Limbaugh, whose career ought to go into eclipse.
Conclusion: The eclipse seemed to give a bit of a boost on signals that normally come in very weakly at midday.
I couldn't do a comprehensive scan because of my center-city location (quite a bit of interference from WDAF and KMBZ where I live -- and KMBZ interference will be worse at my new location, where I think I'll be able to SEE the strange tower-and-a-half DA that KMBZ uses) and because I did have to get back to work!
[end]

I indeed could see the KMBZ towers from the roof of the house that I had bought. WDAF long since became KCSP and KMBZ's transmitter site moved to diplexing on the KCCV site in eastern Kansas City.

 

[DavidEduardo]

Northern lights will desensitize the ionosphere for AM stations at more northerly latitudes. This can present a good opportunity to catch stations to one's south, especially from the Caribbean or Mexico...even if the Northern lights are not visible in your area. In my Midwestern days, when Northern lights were present farther north of my Kansas City location, reception from Minneapolis or Chicago would be totally wiped out and the Cuban stations especially would come roaring in.

I lived about 16 to 18 miles from the transmitter of the 50 kw station on 1100 in Cleveland in the early 60's. On one very auroral early fall evening I had a 10 kw station from interior Venezuela hashing up the local, and by turning my loop antenna, could completely eliminate the Cleveland signal and hear the YV station 100%.

 

[semoochie]

I don't remember that one. Where were you located? The one I experienced in August 2017 in East Tennessee did have night-time-like reception but it was happening west-to-east, with the first station noted being KXEL.

Portland Oregon

 

[formula72]

And where were you when you caught KTXL TV 40 Sacramento?

South San Jose.

I remember coming home from school, and always turning my little 5" black and white TV on, to watch cartoons.

I was tuning between channel 44 (KBHK then), channel 36 (KICU), and down to channel 20 (KOFY).

I remember channel 42 (religious) out of Concord was always bad in our area.

When I went past 42, I picked up a station with cartoons (He-man or Thunder cats I believe) and was like, NO WAY!! It was completely watchable off the small loop antenna attached to the back. The picture was a bit static, but totally watchable. I actually watched it for about 30-45 minutes, to confirm it was KTXL TV40. I turned it off and went to do my homework and then outside for fun stuff. That evening, I wanted to see if I could still watch this channel, and it was completely gone.

It was the coolest thing, watching a station that far away.

This was probably a daytime skip, off the ionosphere.

 

[gr8oldies]

You'd have had troposheric ducting which is not an ionospheric issue.

 

[cc333]

Ah, I carried a 5" portable TV with me everywhere back around 1998-2001.

TV became quite uninteresting when it went all digital in 2009. Totally ruined the fun of it. The digital cliff effect especially.

AM radio on LW/MW/SW is one of the last remaining analog modes in widespread use, despite its decline over the years, and analog is just more fun (there's no cliff effect, so stations remain listenable under far worse conditions that would render a digital signal mostly unreadable).

c