I developed SatBox Cloud, a service for predicting amateur satellite passes and receiving AOS alerts in a smartphone or computer browser.

This web version of SatBox focuses on pass prediction and AOS alerts. It does not include radio Doppler control or antenna rotator control. No dedicated Android app is required. On iPhone, add the site to your Home Screen using Safari.

Main features:

• Predict satellite passes for each user's observing location (QTH)
• Set callsign, latitude, longitude, altitude, time zone, and grid locator
• Select satellites from the NASA.ALL catalog
• Display passes in progress and upcoming passes over the next 24 or 48 hours
• Check AOS/LOS times, peak elevation, AOS azimuth, and countdowns
• Show the satellite name and countdown in red during a pass, with the time remaining until LOS
• View the target satellite's position, visibility footprint, azimuth, and elevation on the map during a pass
• Set satellites for alerts, a minimum peak elevation, minutes before AOS, and allowed alert hours
• Register multiple smartphones and computers under the same account
• Set the number of Web Push notifications and the interval between them
• Tap a notification to view that satellite's pass details
• Check upcoming notifications in the scheduled alerts list
• Hear voice announcements before AOS and at AOS while the pass list is open
• Switch between Japanese and English

For example, your smartphone can receive the AOS time and peak elevation of RS-44 at the configured time before AOS. This is useful when doing other things while waiting for a pass. The service is currently in trial operation.

AOS (Acquisition of Signal) marks the start of a pass when a satellite enters the observing range. LOS (Loss of Signal) marks the end when it leaves that range. A pass is one such transit. TLE (Two-Line Element) data describes satellite orbits and is used for pass prediction.

For initial setup, follow this order: Create an account → Satellite selection → AOS notification settings → Notification devices → Send a test notification.

Note: Web Push notifications and voice announcements within the page are separate features. Web Push requires device and browser notification permission and a network connection. Voice announcements work while the page is open and may stop when the screen is locked or the browser is in the background. Notification sounds, delivery times, and the number and spacing of repeated alerts depend on device settings and delivery conditions.

Screenshot 1: Satellite pass prediction

Check satellite passes from your observing location using the map and pass list. The following screenshots explain registration and initial setup.

Screenshot 2: Login

Open SatBox Cloud. If you are already logged in, the pass list appears.

Select Japanese or English for the display language. Registered users should enter their login ID and password and click Log in. New users should follow the registration link to create an account.

Screenshot 3: Create an account

Enter your login ID, password, password confirmation, and callsign. Passwords must be 8–128 characters long.
Your login ID cannot be changed after registration. To request account deletion, or if you forget your password, send an account deletion request by email.

Enter your observing location's latitude, longitude, altitude in meters, and time zone. Use positive values for north latitude and east longitude, and negative values for south latitude and west longitude. Use Asia/Tokyo for Japan or Asia/Manila for the Philippines.

Leave the grid locator blank to calculate a six-character locator automatically from your coordinates. If entering it manually, use a 4-, 6-, or 8-character locator matching your location.

Select a prediction period of 24 or 48 hours and click Create account and view passes. After registration, you can change your location and prediction period in QTH settings.

Screenshot 4: Main screen

Passes in progress and upcoming passes are listed in AOS order. The list shows the countdown to AOS, AOS/LOS times, peak elevation, AOS azimuth, and alert status. During a pass, the satellite name and countdown turn red, showing the time remaining until LOS.

Use LOCAL and GMT to switch AOS/LOS times between your location's local time and GMT (UTC). Alert hours always use the time zone in QTH settings, regardless of this display setting.

The checkbox beside a satellite name turns alerts for that satellite ON or OFF. This setting applies to all passes of the same satellite, rather than only one individual pass.

Passes outside the alert conditions remain in the list, with “Below minimum peak elevation” or “Outside alert hours” shown in the status. “Scheduled (not sent)” means a notification is scheduled; it does not confirm receipt.

During the target satellite's pass, the map shows its position and visibility footprint. While waiting for AOS, you can check its AOS azimuth. The list updates every 60 seconds. Check the TLE update time, because older data may produce predictions that differ from actual pass times.

Screenshot 5: Satellite selection

Select satellites for pass prediction from NASA.ALL. Choose a satellite under Available satellites, then click > to add it to Selected satellites. Use < to remove it from your selection. >> adds all satellites; << removes all satellites from the selection.

Click Save after making your selection. More satellites require more time for the initial calculation. This page selects which satellites to display; choose which ones generate alerts separately in Notification settings.

Screenshot 6: AOS notification settings

Check the satellites you want alerts for from those chosen in Satellite selection.

• Minimum peak elevation: The lower limit for the highest elevation reached during a pass. For example, 10 degrees allows alerts for passes whose peak elevation is at least 10 degrees. It does not trigger an alert at the moment the satellite reaches 10 degrees.
• Minutes before AOS: Set 0–180 minutes. A value of 0 schedules the notification at AOS.
• Alert start and end times: These use the time zone in QTH settings. The scheduled notification time before AOS is checked, rather than AOS itself. The end time can be 24:00. Overnight periods such as 22:00–06:00 are supported. Identical start and end times allow alerts 24 hours a day.
• Notification count and delay: Set 1–5 notifications per device and a delay of 1–15 seconds between sends. The delay should be at least as long as the notification sound. Device restrictions may prevent every notification from producing a sound.

Click Save and view scheduled alerts and check the scheduled alerts list.

After registering your devices, click Save repeat settings and send a test notification to send a test to all devices registered to your account. Tests ignore alert hours and elevation conditions and can be sent once per minute. This button saves only the notification count and delay. Save changes to satellites, elevation, and alert hours using the upper save button first.

Screenshot 7: Notification devices

Log in to SatBox Cloud on the smartphone or computer that should receive notifications and open Notification devices. You cannot register another device on its behalf.

Enter a recognizable device name, such as Smartphone or your callsign, and click Register notifications for this device. If prompted, choose Allow and confirm the device appears in the registered devices list.

For multiple devices, log in with the same account and register each separately. To stop notifications, use Unregister notifications for this device or the removal button in the list.

Send a test from Notification settings to check the display and sound. If notifications are blocked, follow the Android steps below to allow them. Notifications must also be enabled in your device's system settings.

Screenshot 8: Allow notifications on Android (Chrome)

If Notifications are blocked appears, tap the page information/settings icon to the left of Chrome's address bar. These screenshots show Chrome on Android. Labels and screen layouts may differ by device and version.

Screenshot 9: Open site notification settings

Tap the item showing Notifications blocked. If Permissions appears, open it and select Notifications.

Screenshot 10: Change notification permissions

Tap the notification item showing Not allowed to open its permission settings.

Screenshot 11: Allow notifications and register again

Turn Allow notifications ON. If notifications for Chrome itself are disabled in your device's settings, enable those as well.

Return to Notification devices in SatBox Cloud, reload if necessary, and click Register notifications for this device. Send a test notification to confirm reception.

If there is no sound, also check notification volume, silent mode, and Do Not Disturb settings.

Receiving notifications on an iPhone

1. Open SatBox Cloud in Safari and select Add to Home Screen from the share menu. If Open as Web App appears, turn it ON before adding the site.
2. Open the site using the icon added to your Home Screen and log in.
3. Open Notification devices, enter a device name, click Register notifications for this device, and allow notifications.
4. If necessary, open Settings → Notifications → the added web app's name. Turn Allow Notifications ON and check the display and sound settings.
5. Send a test from Notification settings to confirm reception.

Web Push on iPhone is supported for Home Screen web apps on iOS 16.4 and later. Use the Home Screen icon rather than simply opening a regular Safari tab.

References: Google: Chrome notification settings on Android / Apple: Add a website to your Home Screen / Apple: iPhone notification settings