Mobile Signal and DJI Transfer Issues

Mobile Signal and DJI Transfer Issues | Generated by AI

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I’ll search for information about mobile signal coverage on Dong’ao Island and DJI interference issues.Question: How are the China Telecom and China Mobile signals on Dong’ao Island (东澳岛)? People say China Mobile is good. I use an iPhone and often get “SIM card failed” messages. I noticed that during busy hours of the day, the signal is poor, but during midnight, the signal is better. Also, why does DJI Mini 3 Quick Transfer show “high interference” and only get 300KB/s transfer speed?

Answer:

Mobile Signal Issues on Dong’ao Island

Based on general network behavior patterns and the symptoms you’re describing, here’s what’s happening with your mobile signal:

Network Congestion During Peak Hours

Your poor signal during busy hours is likely caused by network congestion, which occurs when too many devices try to connect to the same cell tower simultaneously, causing signal quality to drop. During peak times like evenings, lunch breaks, and weekends when people are not working, networks experience higher traffic similar to rush hour on roads.

At midnight, fewer people are using their phones, so the cell tower has more available bandwidth for your device, which explains why your signal improves significantly during those hours.

China Mobile vs China Telecom

China Mobile is the largest telecom operator in China and worldwide with over 900 million subscribers, offering extensive 4G LTE coverage and widespread 5G services in major cities. While China Unicom’s coverage reaches nearly 90% of the population, it’s noted that its coverage is not as extensive as China Mobile’s, which suggests China Mobile generally has better infrastructure deployment.

However, on tourist islands like Dong’ao Island, even the best networks can struggle during peak tourist seasons when the local tower capacity is overwhelmed by visitors.

iPhone “SIM Card Failed” Issues

The “SIM card failed” messages on your iPhone could be related to:

Network congestion - When the tower is overloaded, your device may lose connection entirely
SIM card age - Older SIM cards can develop connectivity issues over time
iPhone compatibility - China Unicom is noted for wider compatibility with devices from other parts of Asia, Europe, and Australia, which suggests some carriers may have better device compatibility than others

Solutions to try:

Request a new SIM card from your carrier (they wear out over time)
Restart your iPhone regularly to refresh the network connection
Avoid high-data activities during peak hours (evenings, weekends)
Consider switching carriers if the problem persists

DJI Mini 3 Quick Transfer Interference Issue

The “high interference” warning and slow 300KB/s speeds on your DJI Mini 3’s Quick Transfer feature is a very common problem with several possible causes:

WiFi Interference from Nearby Devices

One user discovered their WiFi router in the same room was causing interference with Quick Transfer. The 2.4GHz frequency band is often crowded because many household devices like microwaves and baby monitors use this frequency, creating signal noise that slows down transfer speeds.

Environmental WiFi Congestion

In high-density urban environments, hundreds of home WiFi routers, Bluetooth devices, and cellular towers compete for the same airspace, creating “electronic smog” that can lead to intermittent connection drops. On a tourist island during busy hours, many visitors using their phones’ hotspots and WiFi networks create similar interference.

Solutions to Fix Quick Transfer Speeds:

Turn off nearby WiFi sources: Move away from WiFi routers, turn off your phone’s WiFi when using Quick Transfer (you only need Bluetooth to initiate the connection, then the drone creates its own WiFi network)
Disable Bluetooth during transfer: Bluetooth operates on the 2.4GHz frequency and can cause direct interference during the handshake process
Optimal positioning: For the fastest QuickTransfer speeds up to 30MB/s, ensure your mobile device is within 2 meters of the drone and using the 5.8GHz frequency range
Check for app/firmware issues: Some users reported Quick Transfer speeds dropping to around 300KB/s after firmware updates, while remote controller transfer maintained speeds around 5MB/s
Try the basic troubleshooting fix: Turn off cellular data and WiFi on your device before opening the DJI app to transfer content

The correlation between your phone signal issues and DJI interference makes sense - during busy hours when the cellular network is congested, there’s also more WiFi and wireless interference in the environment, which affects both your phone’s cellular connection and your drone’s WiFi-based Quick Transfer.

References:

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