If you listen to AM radio stations at night that are just impossible to pick up during the day, chances are you’re benefiting from sky-wave propagation. Propagation is just the technical word for how radio signals travel through the air. Sky-wave propagation is the specific name given to radio waves that travel through the sky. Sky-wave propagation takes place between sunset and sunrise. It’s the flip side to the ground wave propagation used to transmit during the day.
During the day, ground wave propagation is preferable because the radiation from the sun causes so much ionization that radio signals sent into the air are absorbed into the atmosphere. When atoms in the D region of the ionosphere are ionized, you end up with free electrons and ions floating around in the air. It’s kind of like trying to walk through a room filled with dancing couples. When in pairs, there’s more room to walk through, but when they’re not paired, it’s easier to get stuck in a conversation with someone. That’s kind of how the ions and electrons in the D region work. When they’re not combined they look for something else to combine with and that’s how they absorb radio waves. At night, however, once the sun begins to set, the electrons and ions in the D region recombine rapidly – leaving more room for the radio waves to travel a little farther up. Above the D region, the F1 and F2 regions are also recombining, but much more slowly than the D region. When the radio waves hit those regions of the ionosphere, they have a chance to be reflected or bent (some prefer refracted) back toward the earth.
What that means for AM radio listeners is that they’ve experienced the remarkable ability of AM radio signals to travel hundreds of miles farther than during the day. Listening to AM, and scanning the AM dial between sunrise and sunset is a fun way to discover how far a sky-wave signal can travel to reach you. During the baseball season, you can use the sky-wave to tune in some night games played in different parts of the country. In Northern California (where C. Crane is based), as in other places around the country (even up into Alaska), people use the sky-wave to listen to stations like KGO which is a 50,000 watt station located in San Francisco. If a signal reflects off the ionosphere and then bounces off the earth and then reflects off the ionosphere again, it can travel even farther than with just a single reflection. So, as you can see, sky-wave propagation makes it possible to tune in stations that you might not even know about when tuning your radio during the day.
If you ever come across a DX website, or even a shortwave radio website, where someone is really happy about intense solar activity (or lots of sun spots), it’s because more ionization during the day makes for better sky-wave propagation during the night.
If you want to make the most of sky-wave propagation, we’d suggest the CCRadio-2E. With this radio’s fine tuning capabilities you may be able to find a new station almost every night, thanks to the built-in Twin Coil Ferrite® AM Antenna. A smaller version that works great for portability would be the CC Skywave or if you want the ultimate, the CC Skywave SSB. It’s a lot more fun than you might realize, with something as simple as a radio. Here’s a sample personal station log you can use to keep track of what you hear.
We’d love to hear how far away you’ve received an AM signal from its source, and on what radio!
WTNI in Biloxi, Mississippi, 1200 miles using C.Crane SW Pocket
My best DX catch was when I lived in Queens (NY City) way back in 1965. I used an RCA Victor 6 tube radio (which I still have today and it still works fine) with a loop antenna built in back of the set. I heard KFI in Los Angeles. Powerhouse WNBC’s 50,000 watt transmitter at 660 khz. was only about 15 miles from my apartment, but yet I was able to null them without overlapping splatter.
BTW, I love your CC2E radio. AM reception is phenomenal both day and night!
I now live in southeastern Idaho with Salt Lake City 200 miles to the south and Boise 300 miles to the west. During the day KBOI-670, Boise comes in very well even with two mountain ranges between my home and Boise. Also, KSL-1160 and KNRS-570 in Salt Lake City sound exceptionally good (except during thunderstorms) on the CC2E.
Great electronics and nice job with the design of that radio! Bob Ziel – Rigby, ID
My most distant station so far is the 1575 kHz VOA station near Bangkok, Thailand, from El Cajon, CA, a bit over 8300 miles away, using either a Tecsun PL-380 or PL-606 aided by a Select-A-Tenna. 🙂
Honorable mention goes to 594 JOAK from Tokyo, Japan, almost 5600 miles away. This was heard with the PL-380 and Select-A-Tenna, and I have a local AM on 600 (KOGO) about 7.7 miles away in nearly the same direction that runs IBOC.
Both the above examples were a couple years ago or so.
You did an excellent job of explaining the why of radio propagation. Though I understand it I find it difficult to explain to others who little or no radio propagation knowledge.
My best DX on the AM broadcast band is Radio Cayman on 1555 khz using a Realistic DX-302 and a wire antenna 15 feet above the ground from Virginia Beach VA.
My best personal dx receptions both happened in 1989. From my residence in Lancaster,Ohio I was able to copy KFI 640 LosAngeles California at around 5:00 am est using my Superradio 2 on it’s ferrite rod antenna only. I was also able to receive KOA 850 Denver,Colorado on my 1923 RCA Radiola lll A regenerative radio using a 30 foot long wire antenna and Brandes headphones. I have a qsl card from the latter. Colin Stump
My best reception so far was in 2000. I had just purchased a post-war Capehart console and with help from my father we managed to get that 28 tube monster home. I know I shouldn’t have tried it out before having gone through it,but I couldn’t resist it. I was able to get reception on AM and FM,but the volume was extremely low.I then tried the Shortwave and the first thing I heard was in English,but it had an oriental accent.I almost fell over on the floor when the announcer said “The Republic of Vietnam”! This was around 6 PM Eastern,using only the built in loop antenna in the cabinet,and I found out later that the tuner section was missing several tubes! I thought that if it works this great disabled,this should be a real tiger when restored! Prior to this;around the same time as what Colin had mentioned,I woke up early one morning,and was listening to a mid 50’s Zenith Transoceanic at 5:30 AM Eastern,and listened to KFI 640 Los Angeles,and KOA 850 Denver using only the built in Wavemagnet antenna. At the time,I thought that this would have been almost impossible due to the fact that 650 WSM in Nashville is only about 350 miles from here!
My experience is unlike many who have copied stations from afar. I live in a somewhat mountainous area. I have a local station with its transmitter perhaps 15-20 miles away. The signal is fairly good during the day but diminishes to almost nothing at night. As far as I know the station does not reduce power at night. What causes this significant drop in signal quality?
Hi Bob, Thanks for sharing your question. It depends on the station, but many of them change their broadcast patterns at night. Sometimes they may broadcast the opposite direction at night as they do during the day.
Meanwhile while not being able to pick up a nearby station I am often able to pick up KFMB San Diego, KKOH Reno and KGO and KCBS in San Francisco on my 2E radio. Just a bit frustrating.
I live in Lake County, California which has notoriously bad radio reception. At night I regularly receive clear signals from KEX 1190, Portland, OR; KFI 640, Los Angeles, CA; KOA 850, Denver, CO. These 50,000 watt clear channel stations come in clearly on my C.Crane Solar Observer emergency hand crank radio. My Crane 2E doesn’t do nearly as well, I’m lucky to get KGO 810 on that radio. The Solar Observer rocks. My best AM radio was my first, a table model Zenith Superheterodyne given to me by my parents as a child in Los Angeles. The thing had a gazillion tubes in it. I connected the wire antenna to my window screen and one night received WLW from I don’t remember where, Dad said it was in the midwest. I was 7 years old. I am now 76.
WLW is still broadcasting from Cincinnatti.
The main reception problem isn’t the strength of the radio.It is Mexican radio stations walking all over the signal. this is true for almost every distant am station. I’m in very southern Arizona. We need some way of filtering or a highly directional antenna.
With the National Radio Club that is the definition of a DX reception, that it only came in at night but not in the day
Very nice article. Thanks.
hi what frequencies do cell phones use?
Hi Jamie, this may answer your questions: https://www.solidsignal.com/p/?p=2666&d=determine-cell-phone-range-wirelessadvisor.com&mc=07
Listen to the LSU Football games on WWL 870 am from Wilkes Barre, PA. Approximately 1200 miles. CCrane Skywave.
Great information. Thanks!
As a kid I use to listen to Radio Australia out of Melbourne. This was early in the morning before 7am. I live in Pasadena Ca. and use an old Sears 1930’s area radio.
Later on when I turned 19, my folks sent me to Ecuador for a summer to work at
missionary shortwave station HCJB, which is no longer on the air. I am now 78.
excerpt from your very nice article ‘Why AM Listening is Better at Night’:
“Listening to AM, and scanning the AM dial between sunrise and sunset is a fun way to discover how far a sky-wave signal can travel to reach you.”
The way I read the phrase ‘between sunrise and sunset’ , it means daytime hours.
Would it be more correctly stated to have been written as between ‘sunset and sunrise’ (indicating nighttime hours)?
Thanks for being there with all your great products and suggestions over the years. You have made so many hours of radio listening possible.
I heard about C. Crane radios on Coast to Coast AM, a popular overnight show from L.A. I bought a CC Skywave radio to improve reception as I live 700 miles away from WOR 710 in NYC, the nearest 50000-watt station to air that program. I also listen to Coast to Coast on the station from Hartford 1080. Some nights reception is relatively clear but never perfect. Some nights reception is so poor I can’t stand to listen. My Question is if I move up to a higher end C. Crane radio, will the reception improve dramatically? I am in Nova Scotia and with the CC Skywave on some nights I can receive 740 AM in Toronto from Halifax 1000 miles away. I know I can listen online but I have always have been a huge radio fan and at age 73 I don’t want to change. I listen overnight with headphones. Any comments will be appreciated. Regards Bill in Halifax.
Good Day William,
I would suggest our TERK Antenna to pull in better reception on your Skywave. Simply set it next to the radio and it will extend the reception instantly! I added the Orphan link as well just in case you’d like to save some $. They both are Brand new units. One just has been sent back because the customer changed their minds but still is tested by our Technicians to ensure you are still receiving a brand new unit.
My other suggestion is either our NEW EP-PRO radio or the CC Radio 2E. Both have our patented Twin Coil Ferrite AM Antenna built into the radios that would help you pull in better AM stations.
Hope this helps!
So, I notice the epro is about half the price of the 2e. I’m not so concerned about the price as I am about a radio that will pull in AM stations clearly overnight. Not so much interested in ham radio features just AM reception. I’m in a quandry. By the way my skywave is on at least 8 hours a day everyday. Only complaint is some static when I adjust the volume control. Can I cure this with some old school contact cleaner? Regards Bill
Thanks William for commenting on our blog! Due to the lack of control on the spray range and depending on the radio itself, it’s probably not best to insert any liquids into the radio. Like on our CC Pocket, if you were to spray near the thumbwheel dial, it would definitely get inside and ruin the radio. Also regarding the AM reception, I’ll share an example to possibly help you from one of our Facebook commenters when I spoke about static yesterday. He commented: “This is an excellent suggestion. I had a high noise level that was completely ruining my AM reception and causing an S9 noise level on my Yaesu hf transciever. I used my CCPocket radio and tracked the noise source to a wall wart power supply for a cell phone booster in a back bedroom. What a relief to get rid of the noise source!!!”
I’m in San Antonio, TX and I frequently receive XEEP 1600 Mexico City at night. They run at 20,000w non-traditional at night. Some years back they were a clear channel station but now there’s another Mexican station on that frequently just between here and Mexico City which makes it harder to get a good signal. I mainly DX the Mexican stations at night because there are so many from not only Mexico City but also Monterey and Del Rio that blast every night. BTW my main radios are a Tecsun PL-380, Tecsun PL-360 favored because of the rotating antenna and $10 Amazon purchased Horologe H-198 that works amazing well!
Ever since I was a kid growing up on the east coast in New York, I’ve found DX’ing at night on the AM band is fascinating. It was a thrill for me to occasionally hear KSL-1160, Salt Lake City and KFI-640, Los Angeles.
Now that I live in the west, I listen regularly to KOA-850, Denver, KOB-770, Albuquerque and KOMO-1000, Seattle.
Although FM is nice with its hi-fidelity and stereo, the band has nowhere near the coverage that AM has both day and night. One could be in the middle of the mountains in central Idaho where FM reception is virtually non-existent while AM signals are still able to be heard with generally decent reception.
CCRadio2 and older model CCRadioEP are top notch receivers for AM reception. Thanks to built-in 8″ ferri-core antennas plus decent tuners and electronic circuits, both radios are the best in the market for AM reception. – Bob Ziel, Rigby, ID
The problem of am radio reception isn’t just the strength of the radio or antenna. Almost every am broadcast frequency is drowned out by Mexican radio stations. My CC2e is definitely the most sensitive am radio that I have ever owned. The twin coil ferrite antenna is truly wonderful. I don’t know what else can be done unless there is some way to sort out the Mexican stations from the USA. I don’t know of any directional antennas that would help. Who knows how much power the Mexican stations are pushing but it has to be a lot.
Hello, I love my CC Pocket, and 2E CCrane radios. The reception is very good. But my favorite radio of all time was my very first transistor radio that i got for Christmas 1960. It was a GM Sportsman 7 transistor AM radio. It opened up a whole new world for me , as i previously had to listen to a Crosley table model AM radio with tubes in it. It would hum, and the stations would drift after about 15 minutes of listening. I loved my transistor radio. The reception of the 50,000 watt stations was great without any interference from the electric radio with tubes being plugged into the wall. The local small watt stations cut their power just before dark to make way for the 50,000 watt big boys. We always used to call that ” going to skip-land “. I still love AM radio, and listen to far away stations every night. I am now 68 years old. , Dean Mortis, Cortland, N.Y.
I have loved radio since I was a little boy (I’m now 64 years old) and received my first transistor radio for my 12th birthday in September 1967. I thought I was so cool and carried it everywhere I went. I discovered early on that AM reception was much better at night than in daylight, but I didn’t understand why until I read up on the subject after I was grown. My best catch of a really far away radio station was one summer night in 1976. I had been out with friends and was driving around my home town of Centralia, Washington before heading on home. I was driving a 1961 Dodge Lancer with a tube radio ( which I thought sounded better than the transistorized car radios then or now). All at once, a strong radio signal began to come through the radio speaker. I assumed that it was the local AM station for Centralia (KELA AM1470) because I was not very far away from it. So I kept listening. At the bottom of the hour they broke for news and the call sign announced was for a station in Dallas-Fort Worth, Texas! The skip was REALLY in that night, for sure .
Thanks for the very informative article! I’ve been DXing for years without knowing it; back when I was in the Marine Corps and living in South Carolina, I would sit in my car at night and listen to WMMB in Chicago and WOWO in Fort Wayne IN just for some feelings of home. Now I live in middle Tennessee (about an hour west of Nashville) but don’t have to go outside…I just turn on my CCRadio 2E. WBBM is pretty much 5×5 as soon as the sun goes down…and now I know why! Best catches though have been Zoomer in Toronto and Radio Rebelde in Havana.
I hope that your readers understand that your illustration with the earth and ionosphere is seriously, seriously not to scale. In particular, with a 1000-mile-high tower as shown in this, your ground wave might just be that far. But in real life, the transmitter antenna is not even visible from this altitude, and its RF footprint probably isn’t either.
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KNX 1070 Los Angeles in a car radio in Apia (then Western) Samoa
My first DX’ing experience was back in 1983, when I picked up KBOI Boise and KCBS San Francisco as a 13 yr old on a portable Hitachi AM/FM radio and cassette player my parents got me for Christmas. I was shocked radio stations could travel that far at night. And I was hooked. Over the years I would pick up KXL Portland, KOMO Seattle, KSL Salt Lake City, KOB Albuquerque, KDXU St. George, UT, KDWN Las Vegas, KTNN from the Navajo Nation in Window Rock, AZ and Radio Canon from Mexico.
I now live in Honolulu, Hawaii. When conditions are right, I can pick up on my Sony portable radio small 1kw AM stations from Kauai, Maui and the Big Island — 100 to 250 miles away. The water grounding effect from the ocean probably carries those signals further out here since we’re smack dab in the middle of the Pacific.