DX Reminder Setup: An Alarm When Your Wanted Callsign Appears

Every DX chaser knows the feeling: the rare station you need was on the air for twenty minutes, and you were in the kitchen. DX Reminder is the LY4A app that removes this problem. You tell it which callsign you are waiting for, on which bands and in which mode, and from then on it watches the DX clusters in the background and raises a real alarm the moment that callsign is spotted. This guide walks through the whole setup, from installing the app on your device to testing the alarm, and explains each choice you make on the way. Everything here comes from the app and the LY4A website, so you can follow it step by step.

What DX Reminder Does

The app is built around one simple idea. Instead of watching a cluster page or a spotting website all evening, you list the callsigns you want and let the app do the watching. It keeps an eye on five sources at once: DXScape, DXSummit, DXHeat, PSK Reporter and Reverse Beacon. When one of them shows your callsign on a band and in a mode that you have switched on, the app plays an alarm. The alarm uses the alarm channel of the phone, so it sounds even when the phone is silenced, and it wakes a locked screen. On a computer the app keeps running from the system tray after you close the window.

It supports all the HF bands from 160 m to 10 m, including 60 m, plus 6 m, 2 m and 70 cm. The five modes are CW, SSB, FT8, FT4 and RTTY. The app has no account to create, and the Android, Windows and macOS versions keep your callsigns and settings on the device itself. You can read the details on the LY4A website. If you want the background on how spots are produced and why a cluster alert is useful, see our guide to automating DX spot alerts.

Step 1: Install the App on Your Device

LY4A DX Reminder is available for iPhone and iPad, Android, Windows and Mac. The installation differs a little between the platforms, so the table summarises what to expect before you start.

On Android, if you use the APK, tap the download button on the site, open the downloaded file and allow your browser to install apps from this source. Then tap Install and Open. On Windows, run the .msi file and follow the installer, which creates a Start menu entry and a desktop shortcut. On a Mac, open the .dmg, drag the app into Applications and eject the disk image. On macOS 15 and newer you may have to open System Settings, go to Privacy and Security and click Open Anyway after the first attempt. These warnings appear only on the first install, because the app is not signed with a paid developer certificate, and they are not a sign of a problem.

Step 2: Allow Notifications

This is the one setting you must not skip. On the first launch, the app asks to send notifications, and the alarm cannot appear without this permission. If you refuse by mistake, open the system settings of your phone or computer, find the app and turn notifications on. The app also warns you when notifications are switched off, which is useful, because otherwise it would keep watching and alarming without anything to show for it.

On Android, the app may also ask for the Alarms and reminders permission. Allow it, otherwise the system can delay the checks. The phone settings that decide whether the alarm really sounds on a silent phone are the subject of the next article in this series.

Step 3: Add the Callsign You Are Waiting For

After the title screen, you reach the list of reminders. Add a new callsign by typing it in full, for example the callsign of a DXpedition that has been announced for your next weekend. The app lets you watch several callsigns at the same time, and each callsign has its own selection of bands and modes. It is sensible to start with one callsign that you really want, and to test the full chain before you add more.

Type only the call itself, without a comment. If the expedition operates with more than one callsign, for example a main callsign and a special one for a contest, add each as its own reminder. Our article on how to work a DXpedition explains how to find the callsigns, the dates and the planned bands before the team leaves.

Step 4: Choose Bands and Modes

For every callsign you decide on which bands and in which modes the app should alarm. The reminders are shown as a table: each band is named once on the left, and the five modes stand in columns, so one line tells you at a glance what is switched on for 20 m. You tick the combinations you want, such as 20 m CW and 40 m SSB.

The combinations are kept apart, which matters in practice. A spot of your callsign on 20 m CW does not fire the reminder you made for 40 m SSB, and CW means real CW only, so a digital signal on the same band does not trigger it. FT4 has its own channels and is told apart from FT8, so a reminder for one does not fire on the other. This is the reason for the careful selection: if you tick everything, you get an alarm for every spot, including bands where you have no antenna, and you may soon ignore the alarm.

Switching a combination off keeps its frequency

Each combination can also hold an exact frequency and a tolerance, for a case where you want to hear only the spots near one frequency. If you untick a combination later, the app only switches it off. The frequency and the tolerance stay saved, so when you tick it again, the same settings come back. This is a small detail, but it helps when you turn bands on and off with the propagation during the day.

Step 5: Set How Often the App Checks and How Often It Rings

There are two timing choices, and they are easy to confuse. The first is how often the app checks the sources. It can check every 1, 5, 10 or 30 minutes, and it keeps running in the background and after a reboot of the device. A shorter interval means you hear about a spot sooner, and a longer one is gentler on the battery. For a wanted callsign that may appear for a short time, one minute is the logical choice.

The second choice is how often the same station may ring again. A single appearance on the air is reported by many spotters, and a busy DXpedition may be spotted dozens of times in a few minutes. The app gives you one alarm for the newest of these spots. You then decide whether the same callsign on the same band and mode may ring again on every new spot, or only every 1, 5, 10, 30 or 60 minutes. The setting applies to that one callsign, band and mode, so any other station still rings at once. If you are sitting at the radio, a longer repeat time stops the alarm from interrupting you while you work the pile-up.

Step 6: Test the Alarm

Before you rely on the app, test it with a callsign that is certain to appear. Pick a station you can see on a spotting website at this moment, add it as a reminder on the band and mode of the current spot, and wait for the next check. When the alarm sounds, you have confirmed three things at once: that the permissions are right, that the sound is loud enough and that the sources are reachable. Then press Stop, Snooze or delete directly in the notification, without opening the app. Delete the test reminder afterwards, or switch it off so that the settings remain.

If nothing happens, check the notifications permission first, then the volume of the alarm channel, and then whether the device is in a mode that blocks the alarm. If you have the app on more than one device, such as an iPhone and a laptop, remember that each device keeps its own list of callsigns.

Where Your Data Goes

To find out whether a callsign is on the air, the Android, Windows and macOS apps ask the same public cluster services that a person would open in a browser, and each request carries the callsign being sought. The callsigns, bands and modes you chose, your settings and the spots already seen stay on your device. The iPhone version works a little differently: iPhone does not allow an app to keep watching in the background, so for iPhone the watching is done by the LY4A website, which stores an anonymous device identifier, the notification token, your language, your callsigns with bands and modes, and your alarm settings. The privacy page of the site describes this in full, and there is no e-mail address or account in either case.

For background on the sources the app reads, the pages of PSK Reporter and the Reverse Beacon Network show how digital and CW reports are collected from receivers around the world. Both are among the five sources that DX Reminder watches.

Good Habits After the Setup

Keep the list short. Ten wanted callsigns on all bands will produce so many alarms that you will stop paying attention to them. A better list holds the stations you really need, on the bands where you can hear them. Remove callsigns when you have logged them, or when the expedition has ended. Also use your own knowledge of propagation: if 15 m is closed to the target in your evening, a reminder for that band only adds noise.

Finally, keep the app updated. It checks with ly4a.com whether the installed version is still supported, and your callsigns and reminders survive the update. For a wider look at the tools hams use on a phone, our overview of ham radio apps for logging, propagation and DX alerts compares the main kinds of apps.

The Bottom Line

Setting up DX Reminder takes only a few minutes: install the version for your device, allow notifications, add the callsign you wait for, tick the bands and modes where you could work it and choose how often the app checks and how often it may ring again. Test the chain once with a station that is on the air right now, and keep the list of reminders short, so that each alarm means something. Then you can leave the radio for the kitchen without worrying that the one you need will pass unnoticed.

Frequently Asked Questions

What does DX Reminder do?

It watches five DX cluster sources for the callsigns you list, on the bands and modes you choose, and raises an alarm when one of them is spotted.

Which devices does DX Reminder run on?

It is available for iPhone and iPad with iOS 16 or newer, for Android 8.0 or newer, for Windows 10 and 11 in 64-bit and for macOS 12 or newer. Portable versions exist for Windows and macOS.

Do I need an account to use the app?

No. The app has no accounts. Your callsigns and settings are stored on the device, except on iPhone, where the LY4A website does the watching on your behalf.

Why do I have to allow notifications?

The alarm is shown as a notification, so without the permission it cannot appear. The app warns you if notifications are turned off.

Which bands and modes can I choose?

All HF bands from 160 m to 10 m including 60 m, plus 6 m, 2 m and 70 cm, in CW, SSB, FT8, FT4 and RTTY.

How often does the app check for my callsign?

You can set the check to every 1, 5, 10 or 30 minutes. The app keeps running in the background and after a reboot.

Will the alarm ring on every spot of the same station?

You decide. The same station may ring again on every new spot, or only every 1, 5, 10, 30 or 60 minutes. The setting applies to that callsign, band and mode only.