Tag Archives: sporadic e

DX Central SEDAP: A Sporadic Es Data Analysis Dashboard

DX Central Unveils SEDAP: The World’s Most Advanced Sporadic Es Data Analysis Dashboard for the FM DX Community

MANDEVILLE, La. — April 29, 2026 — DX Central is proud to announce the official launch of version 2.0 of our popular Sporadic Es Data Analysis Project (SEDAP), a revolutionary, interactive intelligence dashboard designed to decode the mysteries of VHF propagation. Officially unlocking on Friday, May 1, 2026, at 7:45 PM CDT (0045 UTC May 2) at fmdxdata.com, SEDAP transforms nearly a decade of siloed radio loggings into a massive, cinematic data science suite, completely free of charge for the hobbyist and academic community.

Historically, analyzing Sporadic E (Es) propagation on the FM band has been an isolated effort, with individual DXers tracking their own localized season-over-season metrics and comparing notes with other DXers. SEDAP shatters that limitation by aggregating more than 95,000 North American FM broadcast logs and presenting them with brand new interactive visualizations to give DXers a whole new understanding of this elusive and magical propagation method.

“For years, our understanding of Sporadic E has been largely limited to individual observations,” said Loyd Van Horn, founder of DX Central and creator of SEDAP. “By bringing all of this data together, we aren’t just looking at spreadsheets anymore. SEDAP allows us to physically watch ionospheric clouds spawn, compress, and track across the continent in real-time. We can finally see what a typical season looks like on a macroscopic level.”

Built on a Google Cloud BigQuery architecture, SEDAP boasts a sleek user interface featuring dynamic visualizations, including:

The Es-Cloud Tracker: The newest and perhaps most exciting addition to the SEDAP dashboard. The Es-Cloud Tracker is a cinematic, multi-day playback engine that maps the approximate geographic formation location of FM DX Sporadic Es ionization clouds over North America. Openings can be “played” on a timelapse, allowing DXers to watch a simulation of the Es clouds as they develop, morph and transit throughout the day or a range of days.
Path Line Analysis: In-depth analysis on the most common and productive paths to and from a DXer or station location. Visually “see” the paths that evolved over the span of a day or date range.
Frequency & MUF Forensics: An interactive “SDR Tuner” interface to interrogate large scale band yields, signal paths, and daily Maximum Usable Frequency (MUF) ceilings.
Station & RDS Intelligence: Deep-dive forensics into the WTFDA station database, featuring PI-Code adoption maps, format/slogan correlation matrices, and gamified “Unheard Target” lists for US States and Counties.
DXer Network Intelligence: Long-term seasonal performance audits and multiple normalized metrics to filter out observer bias as much as possible
“We have certainly seen a huge growth in the number of DXers both reporting receptions and the amount of receptions they are reporting thanks to improved technology and resources from SDRs to propagation monitoring through Rabbitears and the FM DX Webservers,” says Van Horn. “So while we are not here to say one season was better than another, we can give DXers insights into Sporadic Es season that can help them strategize antenna placement and bearing, timing of monitoring, potential paths based on different periods within the season and a whole lot more. This is about improving our understanding of what happens when the ionosphere sends those FM signals back down to Earth.”

SEDAP makes no claim of ownership over the raw data presented, acting strictly as an analytical engine. The platform owes its immense capabilities to the unprecedented collaboration and public data provided by FMList.org, and the Worldwide TV-FM DX Association (WTFDA).

To protect the integrity of the database and respect the bandwidth of its data partners, SEDAP is strictly governed by a non-commercial usage policy. Automated scraping and commercial monetization are prohibited, but users are highly encouraged to explore, share, and cite the dashboard’s findings.

The Sporadic Es Data Analysis Project will be accessible to the public beginning May 1, 2026. To access the dashboard, view the real-time launch countdown, or read the full data usage policy, visit fmdxdata.com.

About DX Central: Based in Mandeville, Louisiana, DX Central is a premier hub for the radio monitoring community, dedicated to advancing the hobby of DXing through live streams, online receivers, regular DX challenges and contests, educational content, and data-driven propagation analysis.

Media Contact:

Loyd Van Horn | Founder, DX Central

Email: [email protected]

Web: dxcentralonline.com

Youtube: youtube.com/@DXCentral

Twitter/X: twitter.com/DXCentral

Loyd Van Horn
W4LVH – Mandeville, LA
Member: IRCA/NRC Courtesy Program Committee (CPC)
Founder: DX Central – Because we’re all about radio
Web: dxcentralonline.com
Twitter: @DXCentral
YouTube: youtube.com/c/DXCentral

Sporadic-E and FM DXing

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Many thanks to SWLing Post contributor Alan, who shares this Radio World piece which explores the fascinating world of long-distance FM reception via sporadic-E (E-skip), including rare double-hop events: Double-Hop Dreams and the Mystery of Long-Distance FM

A great read for anyone interested in the world of VHF propagation!

Alan also shared these resources:

Australian Bureau of Meteorology – Propagation Modes: Learn about various propagation mechanisms, including transequatorial propagation.
HeyWhatsthat.com Path Profiler: Calculate great-circle paths, view terrain profiles, and check Fresnel zones. Ideal for evaluating DX paths and terrain obstructions.
FCC FM Query: Look up FM station data, including transmitter location, ERP, and HAAT—helpful for assessing potential reception range, even for low-power stations.

Thanks, Alan!

Summer FM DX: Drive-by Sporadic E

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Many thanks to SWLing Post contributor, TomL, who shares the following guest post:

Summer DX – Sporadic E, FM band

“Sporadic E” DXing is a specialty of some DXers. I have never dabbled in it being content with mediumwave or shortwave listening. However, it was truly fun to spontaneously hear this happen while driving on the Interstate highway, Wednesday August 4 around 6pm Central Time.

To quote from an ARRL propagation article:

“As frequency increases still further, signals will eventually pass through the F1 layer to the F2 layer. Because this is the highest reflecting layer, the distance spanned by signals reflecting from it is the greatest. The maximum skip distance for the E layer is about 2000 km. For the F2 layer that increases to about 4000 km—a significant gain.”

I was listening to the local classical music station WNIU in DeKalb, IL which is a good 50 kW transmitter about 10 miles behind me near the Interstate highway. A different station was breaking through. Eventually, I heard a familiar Christian song “You Make Me Brave” swamp the classical music. I noticed it was a remake of a song made about 10+ years earlier. The two signals fought it out and then I heard the station ID “Spirit FM” and a short humorous segment called “Attitude Adjustment”, then more music. Finally the local classical music station won out and I thought I would look up the station ID of that contentious station later.

When I googled “90.5 Spirit FM”, it came up with a station in Tampa Bay, FL called WBVM. Cool! Just to be sure, I went to the station web site and looked up their playlist and this confirms what I heard:

Curious about the transmitter, Radio Locator said it was a 100kW station and gave the Long/Lat coordinates. I then went to Google Earth and mapped an approximate distance of 977 miles (1572km), give or take 10 miles:

I did not have time to get on the shortwave radio to see if the 10 meter band was busy since I had things to do. But it is a very nice surprise to hear in my old car radio an FM station almost 1000 miles away. For one thing, Analog radio is still fun. Secondly, things are busy this summer if you are at the right frequency and time!

Happy Listening,

TomL

Sporadic E on the Red Planet

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(Source: Inverse)

Thanks to NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) mission to Mars, you may soon never need to fiddle with the tuning dial on a car radio again.

When we listen to songs on the radio, the sound travels via radio waves that are given out by a transmitter and then received by a receiver — in the case of a car, the car’s antenna is the receiver.

Radio waves travel in the form of electromagnetic radiation from one antenna to the other. The journey, however, isn’t always perfect.

Sometimes, there is a sudden spike in the amount of hot gas in the upper layer of Earth’s atmosphere which causes interference in radio communications. If you are tuned into a favorite station, that could result in static, or for one radio station to be replaced by another.

This phenomenon, known as sporadic E layer, is difficult to study on Earth because that part of the planet’s atmosphere is hard to reach with satellites. As a result, scientists can’t predict when they will occur — leaving us to fiddle with dials.

But thanks to MAVEN, a spacecraft traveling 300 million miles away from our planet, we could finally have the solution.

MAVEN detected sporadic E layer in Mars’ upper atmosphere, and scientists are hoping to be able to use the Red Planet as an off-Earth laboratory to study the phenomenon up close. Already, the data have provided new insights into the cause of radio static, which also affects communications with aircrafts and military radars.[…]