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Meeting WavViewDX Developer Reinhard Weiß, and Visiting Akihabara With Him (A Totsuka DXers Circle Article by Kazu Gosui)

Meeting WavViewDX developer Reinhard Weiß, and Visting Akihabara With Him

by Kazu Gosui

I first learned about WavViewDX in January of this year on the mailing list of the American radio club IRCA. It was described as “analysis software compatible with I/Q WAV recordings created with almost all SDR software,” so I was intrigued. I quickly downloaded it and tried it out, and I was immediately impressed.

In early February, I emailed the developer, asking, “I’m amazed at how easy it is to use and how powerful it is. It works fine with PERSEUS and AirSpy HF+, but are there any plans to support WiNRADiO’s DDC format?” Reinhard Weiß (hereafter referred to as Reinhard) responded that same day, “I’m actually currently working on adding support for WiNRADiO’s G33DDC. I should be able to send you a test version tomorrow.” The email carefully explained the import procedure and important points to note.

The text, the web page description, and the tone of the expression conveyed a sincere and attentive personality. The next day, I tried out the sample version and reported some concerns. Reinhard quickly fixed them, and where he couldn’t immediately fix them, he supported me by sending files via the cloud or screen capture videos. As I continued to request things like adding a shortcut for switching receive modes, I gradually became fascinated with WavViewDX and, before I knew it, became a heavy user.

The first email also asked, “I’m planning to visit Japan in May or June. Are there any ham or BCL (Broadcast Listener; SWL) events in Japan around that time?” In response, I suggested that if Reinhard could come to Tokyo, we could hold an offline meeting with members of TDXC! Through our exchange, I realized that Reinhard is quite knowledgeable about Japanese affairs. He knows Akihabara very well, and even knows Hard Off as a good place to get BCL radios. He loves hot springs and enjoys talking about Japanese food. When I asked him, “Is your wife Japanese by any chance?” he replied, “Yes.” No wonder he’s so knowledgeable! He should have told me sooner! (lol) So, we made an appointment for an offline meeting in Akihabara, Tokyo, in late May.

On the day, we met at the Electric Town exit of JR Akihabara Station. Our four attendees were Hiroo Nakagawa, Satoshi Miyauchi, Fumiaki Minematsu and myself. When I arrived at the meeting point five minutes early, they were already there. When I asked him, “Excuse me, Reinhard-san?” he replied, “Yes, that’s right,” in Japanese. His Japanese was fluent! Up until now, emails had been in English, as I don’t speak German, so I had no choice but to communicate in English… I was completely surprised because I had been counting on the others and Google Translate on my smartphone to converse in English! You should have told me sooner, Reinhard! (lol) Needless to say, from then on, the entire conversation was in Japanese. The meeting venue was a pub near the station. He could read the Japanese menu, and thanks to his wife, who is apparently a good cook, Japanese food was also OK, so no problem.

We spoke about radio and BCL. Reinhard started medium wave DX about three years ago. He has been interested in radio since he was a child and actually worked as a BCL radio broadcaster. He has had a long career. His job is developing debuggers for testing and verifying the operation of in-vehicle electronic devices and measuring instruments. He says that both his work and his hobby are focused on developing easy-to-use hardware and software integration. He developed WavViewDX while studying the programming language Python, and runs it at home using two PERSEUS devices.

He said he would be happy if many people use it. Currently, WavViewDX has 200 users, 25 of whom are active worldwide. Incidentally, the mailing list has 102 subscribers (as of June 10, 2025).

Over lunch, we had the opportunity to use WavViewDX on the PC we brought with us, and it was extremely valuable to have the developer himself explain how to use it, provide an overview of its functions, and explain the development concept. We also received copies of the German BCL magazine “Radio-Kurier” (a radio delivery service?). This magazine apparently publishes an astounding 2,000 copies per month, demonstrating the depth of Germany’s BCL population. The most active BCLs are few, and 80% of the articles are written by one person. That’s impressive.

The second half of the meeting was a tour of Akihabara’s famous shops. We visited the Radio Center rental showcase, Uchida Radio, Radio Department Store, Rocket, Fuji Musen, and Akizuki Denshi. Reinhard has a keen interest in vintage Japanese BCL radios and boomboxes, and his eyes lit up as he looked at rare radios and boomboxes. At Uchida Radio, he even negotiated the price of a radio cassette player he was interested in. Unfortunately, the deal fell through, but he apparently toured Hard Off stores around Tokyo the next day, so he must be a die-hard enthusiast. He also seemed to love the Fuji Wireless and Akizuki Electronics stores on the second floor, saying, “Their unique products are what keeps them going, and I can see why they’ve survived.” He bought a large breadboard (brand new!) for 50 yen on the second floor of Akizuki and then we took a break for tea in the cafe.

We had a great time chatting there, too. Reinhard is, in a word, a nice guy. A German who speaks Japanese, loves radio and BCL, and develops software for BCL—an extremely rare and valuable person. He’s fluent enough in Japanese to even tell jokes, and he’d laugh along with us at our old-man jokes. He was friendly and fun to talk to, and we shared the same values as fellow enthusiasts. It felt like we were old friends.

He apparently returns to Japan every year with his wife, but he hasn’t done a DX expedition yet. Maybe the next one will be the Chigasaki expedition?! So we parted ways, hoping to see each other again next year.

(l-r: Kazu Gosui, Satoshi Miyauchi, Hiroo Nakagawa, Reinhard Weiß, Fumiaki Minematsu) —Hiroo Nakagawa photo

(l-r: Kazu Gosui, Hiroo Nakagawa, Reinhard Weiß, Satoshi Miyauchi) —Fumiaki Minematsu photo

These English translations were prepared for IRCA’s DX Monitor, and are used with the kind permission of IRCA as well as of the authors and the editor of the Totsuka DXers Circle publication, PROPAGATION.

Ultra Convenient, The Benefits of WavViewDX: Visualizing Reception Conditions (A Totsuka DXers Circle Article by Satoshi Miyauchi)

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Many thanks to SWLing Post contributor Nick Hall-Patch, who has kindly provided a translation of this article from the Japanese-language publication PROPAGATION by the Totsuka DXers Circle (TDXC). In this piece, Satoshi Miyauchi explores how WavViewDX can revolutionize SDR analysis by making propagation and reception conditions instantly visible–and shares some remarkable reception examples.

“Ultra” Convenient, The Benefits of WavViewDX: Visualizing Reception Conditions

by Satoshi Miyauchi

After recording bands using SDR’s such as Perseus or HF Discovery, I was informed by Kazu Gosui via email of a new program that’s “ultra” convenient for analyzing them. When monitoring in real time with Perseus, I have a general memory and notes of what was received at what time. However, when recording reception data without real-time monitoring, such as during nighttime hours, verifying and analyzing the data across all frequencies takes time. Knowledge and intuition about where to listen are also important elements. While all of this is a skill, I believe that previous tools have been unable to provide a comprehensive view of the day’s conditions. Since I started using WavViewDX, I’ve been using it every morning, efficiently analyzing the SDR recordings I’ve collected.

By the way, recently I’ve been using a timer (the “Scheduler” of SDR Console) to check if the TWR-Africa signal transmitted from Benin, West Africa, is reaching me in the middle of the night. My analysis showed a significant reduction in the time required for confirmation that TWR-Africa was being received before and after WavViewDX was installed, and I’d like to share this with you.

Just to be clear, this article is not intended to be a tedious rehash of the user manual. Rather, it is intended to provide useful, pinpointed tips for use.

I’ll introduce a method I think might be best based on my current setup.
I’ll share some reception reports from my recent morning routine.
I’ll touch on the mysteries of radio wave propagation, a realization I believe is unique to WavViewDX.

But first, a word about WavViewDX: seeing is believing. As shown in the sample image in Figure 5, it visually displays the status of stations received at each frequency, using green bars or white lines, in chronological order, from the lowest frequency band (left) to the highest (right). You can even customize it to analyze North and South America at 10 kHz intervals for TP reception.

The author is Reinhard Weiß from Germany (please see accompanying related articles). It is an incredibly easy-to-use and intuitive software. Once you start using it, you’ll definitely want to keep it.

Figure 5

First, let’s assume you’ll be importing and analyzing data into WavViewDX.

1.) Timer Reception Tips, Using SDR Console

This is a backward-thinking approach based on the fact that WavViewDX can import files in “folders.” The golden rule is simply to store all files from a single session in a single folder. I’ve been using SDR Console as my primary SDR program for a while now, so when I register a scheduler (for timer scheduling), I click “Add date (yyyy-mm-dd) subfolder” under “Folder”, in Figure 6. This allows me to import the entire folder of recording files from that day into WavViewDX, saving me a lot of time. WavViewDX has a “Select Whole Folder” button, which allows me to import files into WavViewDX with a single click (Figure 7). How amazing! Incidentally, I set up bandwidth recording files to be stored in separate 1GB files. The moment I wake up, the files are instantly imported into WavViewDX, allowing me to quickly check the conditions from midnight to dawn before work.

Figure 6

Figure 7

2) TWR-Africa Reception Recording

Even on shortwave, it’s rare to see signals from Africa, let alone on mediumwave. Until a few years ago, I thought this was impossible. However, I discovered that I could record pre-dawn signals from Africa on my home K9AY loop, including the VOA of the Sao Tome and Principe relay on 1530kHz, as well as the famous TWR Africa (Benin) on 1476kHz. Of course, it’s not easy to receive signals every day, so I was not motivated to record them regularly However, after installing WavViewDX, I was able to easily grasp the pre-dawn conditions, and I set up a scheduler to record as many times as possible every day.

Then, one morning, right around 3:30 AM, on the morning of the March vernal equinox, I noticed a very clear bar on the 1476kHz using WavViewDX (Figure 8). By working in conjunction with WavViewDX, it automatically checks offsets in exact carrier frequency being received against the MWList database, and the > mark quickly lights up in WavViewDX, indicating that it’s TWR Africa! I was surprised when I heard the audio. I was impressed by the exceptionally clear reception. There was a slight beat, and it seemed like at least one other carrier was also in the mix. How such clear audio managed to reach and be heard across nearly 13,300 km as the crow flies is a mystery, but it’s still a moving experience.

Figure 8

I asked @lft_kashima LFT Kashima Fishing Radio, who regularly posts information on X, and he said that the signal wasn’t as good on that day at his location. Since we’re both in the Kanto region and a little farther apart, perhaps that’s the problem, or perhaps it’s just the antenna. He uses a north-south loop antenna, while I use a vertical AOR SA-7000.

While I don’t know the full reason or answer, one possible guess: – Wasn’t the arrival direction north-south? – Did it arrive through a duct somewhere? However, there’s no way to know why the duct ended up at this receiving point. It’s a wonder that I was able to receive such a DX station at this point in the solar cycle, when the number of sunspots is almost at its maximum and the A/K Index was far from calm. This makes daily reception all the more meaningful. It’s a moment that makes me admire nature, the work of radio wave propagation. I was able to receive this station again in April, and the links to those two results from 1476kHz – TWR Africa are below:

Received Audio 1: March 19, 2025, 18:35 UTC https://youtu.be/gWORriKCJ7c
Received Audio 2: April 14, 2025, 18:31 UTC https://youtu.be/DfYn-gbp2SY

3) The Mysteries of Radio Wave Propagation Discovered Only with WavViewDX

WaveViewDX already clearly shows the reception status on the vertical time axis, but just before the vernal equinox, a phenomenon in which the propagation conditions deteriorated simultaneously across multiple frequencies occurred, albeit for a short period of time. (Audio Sample https://youtu.be/XhXSQFiGQeo) What is this? Figure 9 shows the actual situation at my location on March 17, 2025, after 18:00 UTC.

Figure 9

1278kHz JOFR Fukuoka RKB Mainichi Broadcasting System 50kw (about 900km distance, 245°)
1287kHz JOHR Sapporo HBC Hokkaido Broadcasting System 50kw (about 1000km distance, 340°)
1332kHz JOSF Nagoya Tokai Broadcasting System 50kw (about 270km distance, 270°)

(*Note: The leftmost bar (1242kHz in the Kanto region) is attenuated with a notch filter)

One of the benefits of WavViewDX is that it visually showed the simultaneous drop in signal strength from domestic and international stations, which had been arriving almost smoothly until 18:00 UTC.

I asked Perplexity AI and searched the literature. These possibilities were listed:

“Regarding the phenomenon of simultaneous attenuation of radio signals in all directions for several minutes during nighttime propagation in the medium frequency band (MF band),” it is believed to be primarily caused by the combined effects of the following factors: –

Ionospheric Variation Mechanism Sudden E-Layer (Es-Layer) Formation A localized increase in electron density in the upper E-layer of the ionosphere (at an altitude of 100-120 km) at night. This thin ionosphere strongly reflects signals, blocking the normal F-layer reflection path. One measurement data showed signal attenuation of up to 20 dB when the Es layer occurred.
F-layer altitude fluctuations: When the F layer (altitude 250-400 km), the main nighttime propagation path, rapidly rises due to thermal expansion, the reflection angle changes, creating a “propagation hole” that causes signals to deviate from the receiving point.
Earth’s magnetic field fluctuations disrupt the electron distribution in the ionosphere, causing a sudden increase in absorption.
Instantaneous changes in solar activity: The emission of X-rays and charged particles associated with solar flares suddenly changes the electron density in the ionosphere, destabilizing the reflection coefficient and resulting in short-term propagation loss.

Although it was able to provide various possible explanations, I was unable to perform any further verification of these answers myself.

An Introduction to WavViewDX SDR Playback Software (A Totsuka DXers Circle Article by Kazu Gosui)

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Many thanks to SWLing Post contributor Nick Hall-Patch, who has kindly provided a translation of this article from the Japanese-language publication PROPAGATION by the Totsuka DXers Circle (TDXC). In this piece, Kazu Gosui introduces WavViewDX, an impressive SDR file playback and analysis tool developed by Reinhard Weiß of Germany.

About WavViewDX, SDR File Playback Software

by Kazu Gosui

Introduction

“WavViewDX,” developed by Reinhard Weiß of Germany, is SDR file playback software. It maps the received signals from SDR-recorded files into bar graphs, with time on the vertical axis and frequency (channel) on the horizontal axis, for each of the following channel separations: medium wave (9/10 kHz), short wave (5 kHz), and FM (50/100 kHz). Clicking the cursor (blue crosshair) plays the received audio. By “visualizing the received signal” through mapping (see also the separate article by Satoshi Miyauchi), you can see at a glance the start and end times of broadcasts, fade in, fade out, channels you should listen to, and channels you don’t need to listen to.

Basic Usage and Screen Description

First, download and install WavViewDX from the WavViewDX webpage (https://rweiss.de/dxer/tools.html). The latest version is version was 1544 as of June 8, 2025, when this was written, but version 1662 is available in October 2025. When you launch WavViewDX, the Main Window (Figure 1) will appear, showing Analysis View, the Operation/Settings Panel, Logbook and Database.

Figure 1

To play back recorded files, you must import them. Click Import to display the Import SDR Recording settings screen. Source files can be selected as single or multiple files, or by folder. Set the reception location, time, channel separation, etc., and begin importing. A progress percentage will appear, and green and white bar graphs will appear on the Analysis View screen. Hovering the cursor over a bar graph and clicking will display a red circle, and the audio recorded for that channel and time will play. Scrolling the mouse will allow you to zoom in and out of the Analysis View.

When you import, a WVD format file is created. Once you’ve imported the files, you can simply load the corresponding WVD file at another time, and the files will be available to play immediately.

In addition to Import and Load, the following settings are available at the top of the Main Window.

Analysis: Allows you to select the file/folder and frequency separation when importing.
Carrier Views: Displays offset frequencies to identify and estimate the received medium wave station.
Database: Links with the MWLIST webpage (https://www.mwlist.org/ul_login.php) to identify and estimate the received medium wave station.
Logbook: For documenting stations heard, along with creation of audio recordings during playback.
More: Allows you to set multiple options, such as manual tuning and contrast setting.
Setup: Allows you to set the sound device and select the file format for recording audio clips during playback.
About: Allows you to select the software version, Help, etc.

The Main Window also displays the frequency list linked to the aforementioned Database and the Logbook. The database frequency list can be selected by region, such as Europe or East Asia. The Logbook allows you to record reception records and associate recorded audio files.

The right side of the Main Window contains the operation and settings panel. At the top are the Frequency Display and Spectrum View. Hovering the cursor over Spectrum View allows you to select PBT (Pass Band Tuning) and NOTCH.

Below these are:

Spectrum Zoom (x1, x2, x4), which expands the spectrum;
Bandpass Bandwidth Presets ([2.5] etc.), which change the reception bandwidth;
Player Time Controls (Play/Pause; -30s etc.), which control the playback time;
Carrier View, which displays the offset frequency; (+/- 30Hz, and can be shifted above and below the nominal .000 frequency)
Demodulator Modes, which change the reception mode.

(Keyboard shortcuts are available for the above functions.)

The AF Highpass Filter adjusts the audio frequency passband to improve intelligibility.
The Spike Filter reduces popping during reception.
Phasing combines two synchronized recording files to reduce same-frequency interference and noise.
NCE (Neighbor Channel Eliminator) reduces interference from adjacent channels.
Binaural allows you to select the sideband of the AF output during playback.
The AF Audio Recorder allows you to record by clicking during playback. Recording formats include WAV, FLAC, and MP3.

As you can see, there are so many features it’s impossible to introduce them all. Detailed adjustments to each function make it even easier to use; it may seem tedious at first, but give the features a try. The user interface is intuitive, so you’ll quickly get used to it. If you’re unsure how to use something, just press the F1 key and refer to the Help.

Actual Usage

Let’s try it out. The import settings are set to MW 9+10kHz Channel Analysis Configuration. Configuration, and other settings are set to default. (editor’s note: “SDR Calibration” allows the use of reference carrier frequencies in the data, for those SDRs without a frequency standard, so that each carrier frequency in the passband will be displayed accurately.) Once the import is complete, a bar graph will appear. Figures 2 and 3 show the analysis view of the actual file import from early May 2025, during the Hachijojima DXpedition showing evening reception; time is UTC.

Figure 2

Figure 3

9kHz separation is used in Figure 2. You can hear the audio from 630kHz at the time indicated by a circle. Black areas of the bar graph indicate no signal, while white to green indicates good signal reception. If you miss an ID during reception, press the up arrow key to rewind the time by 5 seconds and listen again. Click Recording to record the ID.

As you can see, the bar graph color changes from black to white and then white to green over time. This indicates that as the day turns from daytime to evening and then nighttime, channels that previously had no reception begin to receive broadcasts. Sunset on this day was 9:29 UTC (18:29 JST), and the received signal fade in was between 8:30 UTC (17:30 JST) and 9:15 UTC (18:15 JST).

Next, click Analysis and switch to MW 10kHz channel analysis. The Analysis View after switching is shown in Figure 3. This shows the reception status with 10kHz separation. Most channels are black, with a few white spots. There is very little green. In this image, there are certainly no 10kHz channels with good audio, but by clicking on the white, we can see some with faint English talk and music. I checked the database and found that these channels appear to be Hawaiian stations (see orange circle marks in Figure 3) that have been active since around 8:30 UTC.

Also, Latin music was heard on 1230 kHz (Orange circle in Figure 3). This may be Radio Dos from Argentina. By visualizing reception status like this, I was able to determine where to listen and where not to listen. During the Hachijojima expedition in May, I was blessed with outstanding reception conditions from the evening through the early morning hours of the following day, and was able to track 187 overseas medium wave stations, including 165 in Australia, 5 in New Zealand, 2 in Papua New Guinea, Solomon Islands, Tonga, Marshall Islands, Kiribati, Palau, Fiji, Tuvalu, Indonesia, and the Philippines, achieving significant results. Playback and analysis took about a week, which was shorter than usual, thanks to WavViewDX.

Summary

As mentioned above, WavViewDX has proven to be an efficient tool for analysis, allowing users to discover previously unnoticed stations. Since it can play files recorded with various SDRs, we hope that many DXers will use it. WavViewDX is compatible with multiple PC operating systems, including Windows, Linux, and macOS, and is freeware. According to Reinhard Weiß, additional features and enhancements are planned for the future, so we look forward to seeing its future developments. Finally, we would like to express our gratitude and respect to Reinhard Weiß for developing such useful and excellent software.

Reference Materials

WavViewDX Homepage https://rweiss.de/dxer/tools.html
Radio-Kurier – weltweit hören https://www.radio-kurier.de/

Table 1. Supported IQ Formats

ELAD FDM-SW2	Generic RAW recordings
GQRX recordings	HDSDR
Jaguar	Linrad RAW, single and dual-channel
recordings	PERSEUS (*.wav)
PERSEUS P22 (*.P22)	SDR#
SDR Console	SDR Uno
SDRconnect	SpectraVue
WiNRADiO DDC	WiNRADiO RXW (only for G33)
Winrad

Trying WavViewDX on FM

WavViewDX is primarily geared toward medium wave DX, but it seems like it can be used for FM DX as well. The image in Figure 4 shows reception from 79-87MHz using an RSPdx-R2 and an indoor YouTwin antenna. It supports stereo and has good audio quality. With an outdoor antenna, it could also be used for FM DX, such as with sporadic E and other short-lived propagation enhancements.

Figure 4

Beyond DXing: Analyzing Medium Wave Propagation During the 2023 Annular Eclipse

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The following article dives into medium wave (MW) radio propagation during the 2023 annular solar eclipse, building upon insights from the 2017 total solar eclipse when DXers made broadband radio recordings of the whole MW band for the first time. Unlike that previous study, the 2023 research took a methodical approach, with standardized data collection, stable receivers, and GPS-synchronized frequency locking. Thirteen radio enthusiasts across North America and Europe contributed to the study, capturing 10 Terabytes of SDR data. Using Carrier Sleuth software, researchers pinpointed key signal strength variations, with some regions experiencing remarkable boosts in signal during the eclipse. These findings highlight how eclipse-induced propagation effects are not the same as those seen during typical sunrise and sunset transitions. The study opens doors for further exploration into whether these effects are symmetrical and how they might relate to ionospheric thinning along specific signal paths. The article ends by asking assistance from DXers to help ID enhanced signals in the 2023 eclipse data sets.

Medium Wave Monitoring During the 2023 Annular Solar Eclipse—Not Just About DXing

By Nick Hall-Patch, VE7DXR

Background

The 14 October 2023 annular solar eclipse was the first one to cross the continental United States since the total eclipse of 17 August 2017. From a DXing standpoint, 2017 was the first eclipse in which there was widespread use of software defined radios (SDRs) to record the entire medium wave (MW) band throughout the duration of the eclipse. Therefore, it was possible to study eclipse receptions after the fact rather more than had been the case during earlier ones. Several IRCA members recorded the 2017 eclipse on their SDRs, and in the months after the eclipse, data files from several locations were examined. It was therefore possible to evaluate the varying signal strength of KSL-1160’s carrier from four different locations in western America, all from outside the path of totality, and to speculate upon the differences in the responses at each site.

That study of KSL’s strength variations during the eclipse led to a presentation at the St. Louis IRCA/NRC convention in 2018, and eventually to an IRCA Technical column (now IRCA Reprint G-096 at http://dxer.ca/images/stories/2019/irca-reprint-index.pdf) which proved to be of interest to HamSCI, an amateur radio citizen science group that had already been using amateur radio communications as a way to study that eclipse’s effects upon the ionosphere. A version of the article appeared on HamSCI’s website and the SDR files referenced by the article were also hosted by the HamSCI community on zenodo.org, along with SDR data from three further locations in eastern America. (Go to zenodo.org, and search on the phrase “Solar Eclipse 2017 recordings” to examine this data for yourself.) Zenodo is a long-term open repository for scholarly work, and these data sets have since been downloaded hundreds of times.

Why would these 2017 SDR files have been of interest to an organization studying radio wave propagation? Unlike the short duration communications found on the amateur radio bands, medium wave (MW) AM broadcasters, assigned between 525 and 1705kHz, provide continuous signals, many for 24 hours a day. Their carrier frequencies are like steady RF beacons. Any changes in that beacon’s amplitude or frequency at a receiver are likely to have been caused by changes in the path between transmitter and receiver. By using suitable hardware and software, either monitoring a single frequency or the entire medium wave broadcast band using SDRs, the resulting files can allow us to characterize the propagation induced changes that these carriers undergo over time, including variations in signal strength and apparent shifts or spreading in the frequency of each carrier. During a solar eclipse, the brief period of darkness along the path of the eclipse can allow AM broadcasters’ signals to temporarily travel much further than they would normally in the daytime, and it is possible to study variations that occur even more quickly than those occurring daily during sunrise and sunset.

Preparation for the 2023 Solar Eclipse

From a DXing standpoint, the 2017 eclipse SDR files were more than functional, but a closer examination revealed gaps in the data, changes of antennas when it suited the DXer, and receivers that had not been properly warmed up, resulting in recorded carriers that appeared to be drifting. From the standpoint of a scientist, this was “found data” requiring judicious handling and compensation. In addition, the data had been transferred many months after the recording had taken place, and sometimes it was no longer clear how the receivers and antennas had been set up for the recording.

Nearly a year before the 2023 eclipse, HamSCI had decided that it would be interested in examining more MW SDR data, but this time asking that the recording of the data be approached in a more professional fashion. In other words, participating DXers would be asked to think a bit more like scientists for the duration of the recordings. Making recorded IQ files of optimum use to propagation researchers would include the following:

Documenting receiver, software and antenna used, with as many details as possible.
Not making changes in receiver or antenna configuration during the recording period; if absolutely necessary, recording that change in detail, especially the time that it occurred.
Warming up the receiver for several hours before recording in order to minimize apparent carrier drift in recorded signals. Better yet, encouraging participants to use SDRs that were locked to a frequency standard such as the Bodnar GPS reference clock, because a frequency locked SDR’s data would display frequencies with stability and accuracy, and allow characterization of any carrier Doppler shifts.
Making sure that timestamps in their recorded data were as accurate as possible, at a minimum setting the computer clock accurately immediately before recording, and preferably to use a network time protocol (NTP) time client on the computer that would be recording the SDR IQ files.
Starting recording well before maximum totality in their area, until well after that time; one hour before the start of the partial eclipse to one hour after the end of the partial eclipse were suggested as a minimum.
If possible, making additional SDR recordings of, for example, the period from two hours before and after sunset and sunrise on the day of the eclipse, and also making a reference recording of the eclipse time period on another day.

Figure 1 shows the path of the 2023 eclipse and the times of maximum obscuration. Efforts were made to involve monitors in both North and South America, and in the end, 13 participants were involved in the experiment, using 14 sites in Canada, the USA, Mexico and Portugal.

Figure 1

12 sites also included data from local sunrise (LSR) and/or local sunset (LSS)
12 sites also recorded data from the same time as the eclipse period on another date in order to provide a reference of a normal day’s reception conditions
6 sites produced data using an SDR locked to a frequency standard that was disciplined using GPS signals. Three of the remaining sites included a signal from a frequency standard in their data recording.
10 sites recorded using computers that had their clocks updated using Network Time Protocol (NTP); others set computer time manually

About 10 Terabytes of SDR recordings were submitted for analysis, which is one heck of a lot to poke through in order to find signals fading up and down for a few minutes during the course of the eclipse. Fortunately, it was possible to pre-process all of the files using Carrier Sleuth software which allowed visualization of hours of data at a time from each MW channel, all available to 0.1Hz resolution over an 80Hz span centered on each broadcast channel. It was then a fairly quick process to scan through each of the 117 channels of the AM broadcast band for each data set, searching for unusual carrier enhancements appearing during the eclipse time period.

An example is shown in Figure 2, portraying 1650 kHz as logged during eclipse enhancement in Phoenix, AZ by Burke Baumann KF7NP. The thin lines representing various carriers are represented in “hotter” colors when signal strength increases.

Figure 2

Because Carrier Sleuth can rapidly generate a chart for signal strength vs. time for each individual carrier, it was decided arbitrarily that a carrier that increased in strength by at least 10dB during the duration of the eclipse at that site would be deemed to have been influenced by the passage of the moon’s shadow. By that metric, six sites indeed reported that during the eclipse, different broadcast signals appeared from those normally received in the daytime. However, other sites did not, or received only a few traces of carriers during the eclipse period.

Figure 3 shows the various sites that submitted SDR data, indicated by pale blue circles, and within each circle is the number of AM broadcast band channels on which eclipse effects were noted, even if it was just a carrier.

Figure 3

From Figure 3, it can be seen that locations in Canada’s west and in the south and west of the USA were likely to have been influenced most by the passage of the eclipse. In contrast, it appears that those who were in locations of less than 50% of totality were unlikely to have seen much effect from the passage of the eclipse. Continue reading →

How to DX the 2024 Solar Eclipse!

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Many thanks to SWLing Post contributor, Nick Hall-Patch, who shares the following article originally published in the IRCA’s DX Monitor:

2024 Solar Eclipse DXing

by William Scott, WE7W

DXing the mediumwaves promises to be an exciting event on April 8 during the 2024 total solar eclipse. I’ve been mulling over the DX possibilities a lot lately and have come to some conclusions. I think it boils down to three promising DX scenarios:

Scenario 1. For those who live within or very near the path of totality (see Figure 1), I believe best chances of DX would be first to listen to your southwest, along the path where totality is approaching. Darkness will already have happened in that direction, and a certain amount of residual de-ionization of the ionosphere will still remain. After the point of totality passes your location, I would swing my attention to the northeast.

Scenario 2. For those living within about 800 km (or about 500 miles) of the path of totality I believe best chance would be a perpendicular path across the totality path to a point roughly equidistant on the other side. This puts the signal reflection point right at the center of the totality path, or the deepest point of darkness.

Scenario 3. For those living more than about 800 km from the path of totality I believe best chance would be along a line from your receiving site to a perpendicular intersection to the totality path. This should define the greatest shaded path.

I think that scenarios #1 and #2 have the best possibility for DX.

Figure 1 (Click to enlarge)

Across the U.S. and Canada, from its entry at Texas to its exit through NE Canada and into the Atlantic Ocean, the totality path width varies from a maximum of 199 km at U.S. entry to about 160 km at Atlantic exit, or 123 to 99 miles.

Important to keep in mind – skywave signal strength analysis is based almost entirely on the condition of the ionosphere at the reflection point, not at the receiving site. For single hop propagation, normally the reflection point is at the halfway point to the station along the great circle route. That 800 km distance from the totality center I wouldn’t hold as gospel. I’m throwing that figure out as a point where scenario #2 may start to transition to scenario #3.

Timing is of the essence for DXing. The shadow velocity exceeds 1000 mph, increasing from 1587 miles per hour at Eagle Pass, Texas to 3176 mph at Houlton, Maine. You may have only minutes to DX. I’ll be in Rochester, NY at the time of totality, and we are right at dead center. I’ll be scenario #1. My plan is to listen to my southwest initially, where totality is approaching. I’ll be listening particularly for WLW-800 in Cincinnati, OH, WHAS-840 in Lexington, KY, and others along or near that path.

Scenario #2 possibly holds the most promise. Calculate your distance to the path center line and look for stations on a direct line across the totality path and at an equal distance on the opposite side of the path from you. One such scenario might be WSB-750, Atlanta to a reception point in northwestern Illinois, central Iowa, or southern Wisconsin or southern Minnesota. Many possibilities on cross-paths exist here. I feel best results would be with a signal path that crosses the path of totality closest to 90 degrees.

A question was raised about the possibility of DX from Spokane, Washington, an extreme distance from the path of totality. That particular scenario would be scenario #3, more than 800 km to the path of totality. Maximum obscurity should be when northeast Texas (let’s say the Dallas area) is experiencing full totality, as the great circle line to the totality path intersects at approximately 90 degrees to the line at that point. This would be at about 1848 UTC. I would listen for any signals along a great circle path between Spokane to anywhere from the Dallas area and northward. Obviously, Spokane to Dallas is an extremely long one hop path, at about 2450 km. At that distance, the reflection point is near Denver, which will have a solar obscuration of 65.1% at maximum.

A Dallas area reception would be next to impossible I would think, but there are many more stations along that great circle path one could try for. Closer stations will obviously move the reflection point closer and start to reduce the solar obscurity. I did a scan along that path and there are some 340 stations within 200 km either side of the line of the great circle path between Spokane and Dallas.

A presumed Scenario #4.

Another scenario was suggested by Nick Hall-Patch, that of reception parallel to the path of totality and outside the 100% totality band. The 2017 solar eclipse across the northern part of the U.S. was DXed extensively and produced some interesting results, which are well documented in IRCA Reprints. Check their document repository here:

http://dxer.ca/images/stories/2019/irca-reprint-index.pdf

Nick reports: “The receptions of KSL-1160 described in IRCA Reprint # G-096 showed the results of 3 DXers listening across the path of the eclipse (Scenario #2), but the fourth, Dave Aichelman, was monitoring KSL from a location parallel to the eclipse path ( sort of Scenario #1?) and got very good enhancement as well.” We might name this “Scenario #4”.

I checked out # G-096, that documents the KSL reception from the solar eclipse of 2017. It looks like the Dave Aichelman (at Grants Pass, OR) reception of KSL had a mid-path reflection point of about 95% solar obscurity. The distance was 971 km (602 miles). Graphing KSL, I see it has a nice fat low angle takeoff and impressive skywave strength at 900 km, some 1.3 mV/m for that distance. (ed. note: A map of fractional solar obscuration is in Figure 2, easily converted to the percentage figures quoted in this article. )

Better yet, the article indicated Aichelman also received XEPE-1700 across the Mexican border from San Diego too. That was a mid-point reflection obscurity of only about 83% as far as I can deduct from the maps. The distance was 1238 km (769 miles). The mid-path reflection point there was in the neighborhood of 700 km from the central path of totality.

So, DX is indeed possible where both the station and the receiver are off center from the totality path. It’s looking like anything from at least 80% obscurity at mid-path reflection may have some real possibilities, particularly if you are at the end nearest the path of totality. Lower obscurities, perhaps down to 50% or so may even produce results.

Check out these links.

https://nationaleclipse.com/cities_partial.html

https://eclipse.gsfc.nasa.gov/SEpath/SEpath2001/SE2024Apr08Tpath.html

https://eclipse2024.org/eclipse_cities/statemap.html

Using my pattern mapping program which has extensive area search capability, I’ve compiled a list of all US and Canadian stations that fall within the 2024 Solar Eclipse path of ~100% totality. There are 456 stations. Results are drawn from the March 20 FCC LMS database and Industry Canada database. Sorry I don’t have Mexico available.

If you would like this list, download from this link. https://www.mediafire.com/file/125ih5yrmw4puib/2024-eclipse-stations-by-longitude.zip/file

Across the US and Canada, from its entry at Texas to its exit through NE Canada and into the Atlantic Ocean, the totality path width varies from a maximum of 199 km at US entry to about 160 km at the Atlantic exit off Newfoundland, or 123 to 99 miles. 456 stations are found in this eclipse path. I purposely set the path width to 210 km from start to finish. This gives a few km slop on both sides of the 100% totality path for good measure.

Unzip the downloaded .ZIP file, where you will find 3 files. The stations in each file are sorted by longitude, from west to east. This gives us the progression of the eclipse path, with the eclipse starting at the first station in the list and ending with the last station.

File #1 is a simple text file.

File #2 is in .CSV format. You can easily input it to an Excel file.

File #3 is in .HTML format. It includes links to each station’s Google Map latitude-longitude coordinates for the satellite view of the transmitter tower array.

Another link takes you to the FCC AM Query link for that station. I hope these files are beneficial. There should be many propagation path possibilities outside of this list as well.

(reprinted from the author’s blog at https://radio-timetraveller.blogspot.com/ )

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Further sources of information concerning the eclipse include the following websites:

http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2024_GoogleMapFull.html?Lat=43.66400&Lng=-76.13690&Elv=88.0&Zoom=6&LC=1

(Clicking anywhere on this map page will give all the information you need about obscuration, length of eclipse etc.at a given location). Also:

https://www.greatamericaneclipse.com/april-8-2024

https://eclipsewise.com/2024/2024.html

Animations of the path of the eclipse versus time can be seen at:

https://eclipsewise.com/solar/SEanim400/2024_04_08_TSE_400px.gif

http://7dxr.com/4all/100km8Apr-movie–Frissell-HamSCI.mp4

The latter is particularly interesting, as it shows the moon’s shadow at 100km height above the earth, an area of special interest to DXers, as it is the lower edge of the E-region of the ionosphere. Note especially that as the eclipse ends over the North Atlantic Ocean, that there is a temporary darkness path between Europe and North America, because night will already have fallen in Europe. So will there be blips of TA DX in eastern North America as the eclipse passes by? Listen, and find out!

Finally, our DX could be of interest to ionospheric physicists also. The rapidly changing listening conditions will be indicating a similarly turbulent ionosphere, and DXers’ documenting those listening conditions through SDR recordings could provide information that will be useful to scientists who want to gain a better understanding of the Earth’s ionospheric dynamics.

HamSCI is an organization of volunteer citizen-scientists and professional researchers who study upper atmospheric and space physics, and will be interested in examining MW DXers’ wideband SDR recordings made during the eclipse period, and indeed, in having DXers assist with HamSCI’s research. (see https://hamsci.org/eclipse. Especially if you are an amateur radio operator, there are several other ways that you might also contribute to the project.)

(This first appeared in IRCA’s DX Monitor and is used with permission. See https://www.ircaonline.org/default.php for club details)

HamSCI Reminder: Contribute to ionospheric research during the October 14, 2023 solar eclipse!

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Many thanks to SWling Post contributor, Nick Hall-Patch, who shares the following announcement:

How DXers can contribute to ionospheric research during the 14 October 2023 solar eclipse

There will be an annular solar eclipse on 14 October, 2023 when, at totality, the size of the Moon’s disk will appear slightly smaller than the size of the Sun’s disk. This eclipse will affect all of North America, as well as Central and part of South America, as seen in the map below.

AM Broadcast Band DXers know that the blocking out of radiation from the sun during a total solar eclipse can introduce temporary night time listening conditions over an area far beyond the path of totality.

The upcoming annular eclipse is expected to have a similar effect on daytime medium wave listening conditions as would a total solar eclipse, and should not be missed by DXers. Live listening can be done during the eclipse, as well as recording the entire medium wave band, using SDRs (software defined radios).

There might be more to our DXing results than new and unexpected receptions of distant radio stations, however. The rapidly changing listening conditions will be indicating a similarly turbulent ionosphere, and DXers’ documenting those listening conditions through SDR recordings could provide information that will be useful to scientists who want to gain a better understanding of the Earth’s ionospheric dynamics.

How can DXers contribute to ionospheric research?

HamSCI is an organization of volunteer citizen-scientists and professional researchers who study upper atmospheric and space physics, and will be interested in examining MW DXers’ wideband SDR recordings made during both eclipses, and indeed, in having DXers assist with HamSCI’s research. In fact, IRCA members contributed to HamSCI’s work about the 2017 total solar eclipse by contributing their DXing results: https://hamsci.org/sites/default/files/publications/2019_am-eclipse2017_hall-patch.pdf

HamSCI is still welcoming experienced medium wave DXers who are using good quality SDRs, especially in the southeastern USA and in Latin America. Please go to https://hamsci.org/mw-recordings/ and discover how to make sure that those DX files will also qualify as scientific data that can become part of the public record.

It will be important to have many participants in this project. To sign up, please go to https://hamsci.org/mw-recordings/ and discover how to make sure that those DX files will also qualify as scientific data that can become part of the public record.

Those interested in finding out about all the research that HamSCI will be doing during the upcoming eclipses, check out https://hamsci.org/eclipse . Especially if you are also an amateur radio operator, there are several other ways that you might contribute to the project.

But, even if you can’t contribute to scientific research, don’t forget to get out there and DX during the eclipse. You might be surprised at what you can hear.