Category Archives: AM

Rediscovering Simple Radio Joy with the XHDATA D-219

by Thomas (K4SWL)

It’s been a long while since I’ve written a receiver review. Years ago, I cranked them out several times a year and genuinely loved the process–evaluating performance, quirks, economics, and overall user experience. Writing reviews is, to this day, one of my favorite things to do.

But over the past four years, my reviewing work shifted more toward amateur radio and portable operations, especially as my QRP activities ramped up. And as many of you know, the SWLing Post now has an incredible group of contributors who regularly write thoughtful reviews, taking some of the pressure off of me.

So when my contact at XHDATA reached out a few weeks ago asking if I wanted to try two new color variants of their ultra-affordable D-219, I surprised myself: instead of passing it along to one of our contributors, I decided I wanted the chance to revisit the world of simple, inexpensive portables firsthand.

Why? Because I’d been hearing surprisingly positive things about this little radio—and because it reminds me of the DX-397, a tiny analog portable I used for years after working at RadioShack right out of college.

This review, then, is less about testing a product and more about rediscovering the joy of having a simple, super-basic radio at hand.

Disclosure: XHDATA is a generous long-time sponsor of the SWLing Post. They sent both of these D-219 radios free of charge. Honestly, I don’t know many companies that would send out a sub-$20 product as a review loaner–it probably costs them more in shipping.

As always, I’ll be gifting these units back out once I’m finished. And in this case, I’ll also be buying three more myself for Christmas gifts… one of those, I’ll keep.

Design & First Impressions

Let’s be clear: the D-219 is a simple radio. It looks like something straight out of the mid-1990s, with:

an analog tuning dial
band-switching sliders
a dedicated on/off switch on top
a small, lightweight plastic enclosure

But inside, it’s very much a modern radio. The D-219 is based on the Silicon Labs Si4825-A10 DSP chip, meaning that although tuning feels analog, you’re actually listening to a DSP-based receiver stepping through the band in predetermined increments.

XHDATA sent me two new color options: off-white and light silver-green. Both look great in person.

Using the D-219 Outdoors

I used my truck tailgate to hold the D-219 while stacking firewood.

Over the past couple of weeks, I’ve been doing a lot of work outside—stacking firewood, yard projects, general winter prep. The D-219 became my little companion radio during all of it.

I mostly listened to:

Mediumwave
A bit of shortwave
and FM radio

Audio Quality

The audio surprised me. It’s a tiny speaker, so don’t expect brilliant fidelity, but it’s perfectly listenable and cuts through outdoor noise when the volume is up.

Performance

FM performance is excellent—far better than I expected. I have a handful of “benchmark” distant FM stations that many small portables struggle to hold onto. The D-219 locked onto them easily. DSP chips often shine in FM, and this was no exception.

Mediumwave was the biggest surprise. I have a regional AM station–WTZQ 1600 kHz–that I enjoy during the day, especially around the holidays. Only about half of my small portables receive it well enough to be pleasant.

The D-219 locked it in better than most of my other inexpensive portables.

That alone impressed me.

Shortwave performance is quite good for the price. Sure, it lacks an adjustable filter, and tuning steps mean you don’t get that smooth, fluid band-scanning experience like a proper analog receiver. But overall, it works pretty well.

On 31 meters, for example, tuning felt natural and not cramped–something many ultra-cheap shortwave radios struggle with. It helps that the selected shortwave bands have enough tuning bandspread that you don’t have to use micro adjustments during tuning (I’m looking at you, XHDATA D-220!).

Back in the Cold War era, when the bands were jammed shoulder-to-shoulder, a radio like this would have been harder to use. But today, with fewer simultaneous signals, it’s totally workable.

Real-World Utility

In the aftermath of Hurricane Helene, I’ve become even more vocal about keeping at least one AM/FM/SW radio as part of your personal preparedness kit. The D-219 checks many boxes:

Runs on AA batteries
Very low power draw
Lightweight and pocketable
Small enough to disappear into a backpack or glove compartment

I’ve been using mine heavily for two weeks on a pair of Eneloop rechargeables and haven’t had to recharge yet.

Two of the D-219s I’m buying will be stocking stuffers for my daughters, just so they always have a reliable source of news and info while at university–even if the power or internet goes down.

Why This Radio Works

The band spread is generous compared to the D-220

I’m sure own more than three dozen portable radios here at SWLing Post HQ—from high-end benchmarks to tiny ultralights. Normally, I advocate for buying a good-quality receiver instead of “throwaway” electronics.

But I don’t think the D-219 is a “throwaway” radio; being based on the Silicon Labs DSP architecture, it doesn’t have an insane component density–inside, its board is almost roomy. Looking at it, I think I could make modest repairs myself as long as the chip still functions.

Sometimes simple designs translate into long life rather than an early landfill destiny. Of course, only time will tell, and I will post an update if my radio experiences any issues.

This is why I’m comfortable giving them to my daughters as everyday radios. And frankly, I’d much rather they lose or break a $13 D-219 than my old Panasonic RF-65B, PL-660, or ICF-SW7600GR–some of my most cherished (and irreplaceable) legacy portables.

The D-219 is also a perfect glove box radio. One to grab and listen to when you’re waiting on your spouse/partner to finish a yoga class, or waiting on your kids at schoool.

In Summary

If you’re looking for a true benchmark portable, obviously, this isn’t it.

But if you want:

a fun, capable, ultra-affordable little radio
something to give as a holiday stocking stuffer
a simple preparedness radio that uses AA batteries
a pocketable MW/FM/SW companion
a “leave-it-in-the-car” radio

…the XHDATA D-219 genuinely delivers for well under $20 each.

And as someone who hates e-waste and often avoids ultra-cheap electronics, I’m betting this radio will age better than most. Its internal design is refreshingly simple and built around the reliable Si4825-A10 DSP chip. There just isn’t much inside to fail.

For the price, performance, and sheer fun factor? The D-219 is a solid option.

Purchase options:

Buy directly from XHDATA
Purchase from Amazon.com (note: this affiliate link supports the SWLing Post)

Giuseppe’s Clever Homebrew Ferrite Antenna for MW and SW Listening

Carlos Tunes Into an Earthquake Alert on NHK

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Many thanks to SWLing Post contributor Carlos Latuff, who writes:

I was listening to the news on the radio when I was caught by surprise with this earthquake alert!

NHK earthquake alert, listened in Porto Alegre, Nov 25, 2025, 09h09 UTC:

Click here to view on YouTube.

Configuring the “News Cruiser” for your emergency radio

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By Jock Elliott, KB2GOM

Rob, W4ZNG, endured three weeks without electricity on the Mississippi Gulf Coast as a result of Hurricane Katrina.

When he and I spoke about his experience (and what any one of us might want in our “fertilizer hits the fan” radio kit), he mentioned that during Katrina, all of the local broadcasters were wiped out. There was a local low-power FM broadcaster who got permission to increase power to 1,000 watts and was broadcasting where to get food and water. There was a New Orleans AM station that was on the air, but all of its coverage was “New Orleans-centric.” After a few days, some local FM broadcasters, working together, cobbled together a station that they put on the air and began broadcasting news. Rob also began DXing AM stations at night to get additional news.

Hold that thought for a moment.

A few weeks ago, Andy, W2SRA, pops up on the Radio Monitoring Net (which I run on Tuesday nights) with a list of “Rolling News” medium wave stations that can be heard at least some of the time from my location in the Capital District of New York State. Rolling news stations broadcast news ‘round the clock.

The list includes:

780, WBM, Chicago, IL
1010, WINS, New York City
1030, WBZ, Boston, MA
1060, KYW, Philadelphia, PA
1090, WBAL, Baltimore, MD
1130, WBBR, New York City
1500, WFED, Washington, DC

When I saw that list, I thought “This is a pretty good resource.”

Then a day ago, something clicked, the lightbulb went on, and I realized: “This is exactly the list of stations that I would want if I were in the same situation as Rob after Katrina, where my local stations were dark, and I wanted to know what was going on! I named the list: the News Cruiser.

So, in the predawn hours, I decided to put the News Cruiser list to the test. I plugged the frequencies into several of my radios, and here is what I found. With the CCrane Skywave SSB 2, the signals ranged from copyable with noise to marginal to uncopyable, depending on the station. With the CCrane CCRadio SolarBT the results were better, but often tough to copy. Neither of these radios has the ability to connect to a medium wave loop antenna through a direct wired connection, although they can be inductively coupled to a loop such as the Terk AM Advantage.

The CCrane 2E, a much bigger radio with a much bigger internal ferrite bar antenna, produced markedly improved results. All three of these radios can be powered by off-the-shelf AA or D cells, which I considered to be an advantage during an emergency.

Two other radios, the Qodosen DX-286 and the Deepelec DP-666, which are powered by rechargeable batteries, acquitted themselves quite well when hardwired to the Terk AM Advantage loop antenna, but I prefer radios that can accept off-the-shelf commercial batteries.

If you live in North America, you can create your own News Cruiser list for your emergency radio by consulting https://radio-locator.com/ and using the search function to find stations that broadcast in the “News” format.

Once you have assembled your list, test it out with the radio you would grab in an emergency and see how well they perform. You might find the perfect combination that you like or you might discover that there is some room for improvement.

In any event, I heartily recommend that every household has an emergency radio that can be easily deployed to discover essential information when the fertilizer hits the fan. The point is to discover what works for you and to discover it before it is needed.

Further, I would very much like to know what works for you no matter where in the world you are located. Let me know in the comments below.

Paul Reviews the Radtel RT-880G

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by Paul Jamet

Looking for a versatile radio?

Which radio listener hasn’t dreamed of owning a portable multi-band receiver allowing them to explore the widest possible radio spectrum?

For nearly a year now, walkie-talkies have appeared on the market which, beyond the classic VHF–UHF functions, also allow listening and transmitting on CB (27 MHz) as well as listening to LW/MW/SW bands (LSB/USB/CW). The RADTEL RT-860 has won over those who have tested it.

Read here: Dan Reviews the Radel RT-860

The arrival of the Quansheng TK-11 — available in three versions — has caused quite a stir on social networks. Then, almost at the same time, the RADTEL RT-880 and RT-880G (G for GPS) appeared, also sold under other names such as iRadio UV98.

Among all these available models, I chose — as a radio listener, especially when I’m traveling — the RADTEL RT-880G. My choice is explained mainly by its antenna connectors (SMA-Female and SMA-Male), its large color display, its GPS module, its thousand memory channels, and the possibility of simultaneously monitoring three VHF/UHF frequencies. This device is highly customizable, but its user manual would deserve to be much more detailed and explicit.

The RT-880G comes with a “standard” 18 cm antenna for VHF-UHF bands, which is also used for FM station reception. I haven’t yet tested the device on the 27 MHz (CB) band, for which a dedicated antenna is preferable. No antenna is provided for LW/MW/SW listening.

For listening to LW/MW/SW bands, the device is often shown with small donut-type loop antennas (10 cm diameter).

However, for easier transport, I simply chose this small telescopic SMA-Male antenna, 48 cm long (weight: 20 g): to which it is possible to clip a wire antenna, such as the SONY AN-71, which can prove very useful.

I also used an antenna normally intended for CB, the ABBREE 27 MHz telescopic antenna (130 cm), admittedly heavier (weight: 78 g) and bulkier, but which gives very good results for the HF band.

The purpose of this contribution — which concerns only listening — is to arouse curiosity among mobile (or stationary) listeners, to invite those who own this walkie-talkie to come here and share their experience, and to collect your comments. It is therefore not a full review of the RT-880G, but simply an illustration of what it offers for listening to LW/MW/SW bands.

For LW/MW/SW bands, the RT-880G allows you to set the:

step to 1 – 5 – 10 – 50 – 100 – 500 – 1,000 – and 9 kHz],
bandwidth [0.5 – 1.0 – 1.2 – 2.2 – 3.0 – 4.0],
AGC (Automatic Gain Control)
BFO – (Beat Frequency Oscillator) – used for fine tuning SSB reception (the minimum step being 1 kHz).

Sample Recordings

Local park where some of the recordings were made.

Here are a few audio files that will help you form an opinion. The recordings were made with a smartphone placed near the receiver. The recordings were made using a smartphone placed near the receiver. The sound quality is quite good, even surprising. Continue reading →

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.

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.

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.