DX Reminder Alarm on a Silent Phone: Android Settings That Matter

An alert that does not sound is worse than no alert at all, because you trust it and walk away. The DX Reminder alarm is designed to ring even when the phone is silenced, but modern Android has several layers of protection that can hold an alarm back without telling you: notification permissions, battery saving, restrictions on full-screen alarms and the way a given make of phone treats background apps. This guide goes through each of them in the order in which they usually cause trouble, explains what the LY4A app checks for you and shows how to test that the alarm really wakes the phone. The same ideas apply, in simpler form, to the computer versions of the app.

How the Alarm Is Meant to Work

When DX Reminder finds your callsign on one of its five sources, it does not just add a line to a list. It plays the alarm on the alarm channel of the phone, which is separate from the ringer and media volume, and it wakes a locked screen. The Stop and Snooze buttons are on the notification itself and visible without expanding it, and you can also delete the reminder from there. Closing the full-screen alarm with the Back button stops it as well. On a Windows or Mac computer the app keeps running from the tray, so closing the window does not end the watching.

If you have not installed or configured the app yet, begin with the setup guide in this series, which covers the first launch, the callsign list and the choice of bands and modes. This article assumes that you already have a callsign in the list and want to be sure the alarm will reach you.

The Five Things That Can Hold an Alarm Back

Most failures come from one of five causes. The table lists them with the symptom you notice and the place to look. The sections after it explain each one in turn.

1. Notifications

The alarm is built on a notification, so if notifications for the app are off, there is nothing to show. The app asks for this permission on the first launch, and it warns you if notifications are later turned off, because before this warning existed the app could keep watching and alarming with nothing to show for it. If you see the warning, open the notification settings for the app in the system and switch them on. Check also that the alarm category of the app has not been silenced separately, since Android lets you control each channel of an app on its own.

2. Alarms and Reminders

On newer versions of Android an app that sets exact times needs a special permission, usually called Alarms and reminders. DX Reminder asks for it on the first start. If you answered no, or if an update of the system reset the choice, the checks can be delayed by the system, so a spot that appeared at 19:02 may reach you at 19:15 or later. Open the special access settings in the system, find Alarms and reminders, and allow the app. It is a small change with a large effect, especially if you use the one-minute check interval.

3. Battery Saving

Battery saving is the most common reason why background apps stop working. Android puts apps to sleep to save power, and it may pause the watching of an app that you have not opened for a while. The Android operating system works on this principle: when the device is idle, the system limits the network access and the timers of apps. A DX alert app must run its checks regularly, so it depends on being allowed to run in the background.

Since version 4.2 of the Android app, the settings screen checks whether battery saving is holding the app back and leads you directly to the right system screen. Use that shortcut rather than searching through the menus, because the path differs from one make of phone to another. On some phones the setting is called unrestricted battery use, on others it is an exception list for optimisation. Whichever name you find, the aim is the same: the app must not be put to sleep.

Manufacturer extras

Some makes add their own task killers on top of Android, with names such as auto-start, protected apps or sleeping apps. If the alarm still comes late after you have changed the standard settings, look for such a list in the settings of your phone and make sure that DX Reminder is not in it. The app keeps running in the background and after a restart of the device, but a manufacturer tool may stop it anyway.

4. Full-Screen Alarms on Android 14 and Later

Since Android 14 the system gives full-screen alarms only to apps that it treats as alarm clocks. If the app is not allowed, the alarm still appears, but only as a normal notification that may light the screen briefly or not at all, so a locked phone on a night table will not show the full alarm. The app now checks this permission as well and leads you to the right system screen. If you ever see a small heads-up notification and no full-screen alarm, this is the first place to look. You can read the general background in the list of changes between versions on Android version history.

The app itself runs on Android 8.0 and newer, and it has been built against Android 16, so it follows the current rules of the platform. The more recent the version of your system, the more likely it is that you have to confirm one of these permissions by hand.

5. Volume and Sound

Because the alarm uses the alarm channel, the volume that matters is the alarm volume, not the media or ringer volume. Open the sound settings and set the alarm volume to a level that you will hear from the next room. Check also that Do Not Disturb is set to let alarms through; by default this is usually so, but it is worth a quick look if you use a custom schedule for the night.

Since version 4.2, the app settings let you choose the sound of the alarm. You can pick one of the system alarm sounds or any music file on the phone. If you select a file and later delete it, the system sound comes back, so the alarm never falls silent. A distinctive sound is a good idea for a DX alarm, because it helps you separate it from the alarm clock you use for waking up. A clear, short tone or a piece of a CW callsign recording works better than a soft melody.

Watches and Other Devices

If you wear a smartwatch paired with the phone, the notification is mirrored to it. A watch does not draw the extra buttons of the notification, so earlier versions showed only the frequency and mode on it. In version 4.2 the spotter and the source travel with the notification itself, so a glance at the watch shows who reported the station and where. This is useful when you are away from the shack and want to decide whether it is worth going back.

On Windows and macOS the same logic applies in a simpler form. Allow notifications for the app in the system, and leave it running in the tray. If you close the window, the app keeps checking. Quit it from the tray menu only when you really want to stop the watching.

Living With the Alarm at Night

Many DX openings happen in the small hours, and a reminder for a rare station on 160 m or 80 m may well be meant to wake you. If that is your plan, think about the whole chain. The phone should be on the charger, because a night of regular checks uses more battery than a night of sleep. The charger should not be on a power strip that is switched off by a timer. The alarm volume should be tested at the distance of your bed, and the phone must not be inside a pillow or a thick case that muffles the sound.

It is just as important not to be woken for nothing. Keep night reminders for the callsigns that you really need and for the bands where your antenna works. A reminder that fires at three in the morning for a station you can never hear will teach you to switch the whole app off, and then it will not be ready for the one night that counts. A longer repeat time for the same callsign, such as 30 or 60 minutes, makes sure that a busy expedition does not ring all night, while a first alarm still reaches you at once. Remember that the repeat time applies only to that one callsign, band and mode, so another station of your list still rings immediately.

Travelling and Changing Time Zones

When you travel, the alarm does not depend on your home location, because the sources report spots from all over the world. What changes is the local time of the opening. A target that is strong on 20 m at your evening may come in at a very different hour of the clock where you are. Before a trip, look at the list of reminders and switch off combinations that make no sense for the new place, and test the alarm sound once in the hotel, where the room, the volume and the Do Not Disturb schedule may differ from home. The settings you made, the callsigns and the reminders stay on the device, so you do not have to enter them again. For a wider view of what else belongs on a ham radio phone, see apps for logging, propagation and DX alerts.

A Short Test Routine

Do the following test once after any change of phone, any large system update and before an important DXpedition.

• Lock the phone and put it on silent, with the alarm volume turned up.
• Add a callsign that is on the air now, on the band and mode of its current spot, with a short check interval.
• Wait until the next check and watch what happens: the screen should wake, the alarm should sound and the buttons should be visible.
• Press Snooze, then trigger it again, and press Stop. Then delete the test reminder.

If the alarm arrives late, work down the table above, starting with battery saving. If it arrives without sound, check the alarm volume and the chosen sound. After the test, use your normal reminders for the stations you really want, and for good habits on the air once the alarm has called you, read about working a pile-up as a chaser.

The Bottom Line

The DX Reminder alarm is meant to ring on a silent, locked phone, but Android can hold it back through five settings: notifications, Alarms and reminders, battery saving, full-screen alarms on Android 14 and later, and the alarm volume and sound. The app checks the last two permissions of the system for you and leads you to the right screen, so start from its settings. Run the test routine after every big change of phone or system, and you can rely on the alarm when the callsign you need finally appears. For ideas on how to choose which stations deserve an alarm, see the guide to filtering DX cluster noise.

Frequently Asked Questions

Does the DX Reminder alarm sound when the phone is on silent?

Yes, it is meant to. It plays on the alarm channel and wakes a locked screen, so the ringer and media volume do not decide whether you hear it. The alarm volume and Do Not Disturb settings still apply.

Why does my alarm arrive late?

The most common reasons are battery saving that pauses the app and a missing Alarms and reminders permission. The app settings check for these and lead you to the right system screen.

What changed with full-screen alarms on Android 14?

Android 14 and later give full-screen alarms only to apps that the system treats as alarm clocks. If this is not allowed, the alarm shows as an ordinary notification.

Can I use my own alarm sound?

Yes. Since version 4.2 you can choose one of the system alarm sounds or any music file on the phone. If the file is deleted later, the system sound is used instead.

How do I stop or snooze the alarm?

Use the Stop and Snooze buttons on the notification, which are visible without expanding it, or press Back on the full-screen alarm to stop it.

Does the app need notifications to be allowed?

Yes. The alarm is shown as a notification, and the app warns you if notifications are turned off.