ESP32 Sonar to Android Wi-Fi Strengthening

ESP32 Sonar Data Streaming to Android Phone – 300–400m Direct Wi-Fi Link, No Repeater

I am looking for an experienced embedded/RF developer to build a reliable wireless communication system for a fishing boat sonar.

CURRENT SETUP

On the boat:
- Sonar
- Existing sonar driver
- ESP32

On shore:
- Android phone

WHAT I NEED

I want the following architecture:

DRIVER → ESP32 → Wi-Fi AP + external antenna → 300–400m → Android phone → APK

The Android phone must connect DIRECTLY to the boat.

STRICT REQUIREMENTS

- 350–450 meters real-world range
- Direct boat → phone connection
- NO repeater
- NO router/access point on shore
- NO additional radio receiver on shore
- NO internet connection required
- Android phone must receive the data directly using its built-in Wi-Fi
- Low latency
- Fast and stable data transmission
- Ideally real-time sonar image/data streaming
- The boat should create its own wireless network
- The Android APK should connect to the boat and display the sonar data

The current ESP32 setup reaches approximately 200 m, but I need to improve the system to reliably reach 300–400 m.

I NEED THE FREELANCER TO

1. Analyze the existing ESP32/sonar communication.
2. Recommend the appropriate Wi-Fi hardware/module.
3. Design the antenna/RF configuration for 300–400 m.
4. Keep the connection directly between the boat and Android phone.
5. Develop or modify the Android APK to receive and display the sonar data.
6. Optimize latency and throughput.
7. Test the system at approximately 300–400 m.
8. Provide the complete source code and wiring/configuration documentation.

IMPORTANT

I am NOT looking for a repeater-based solution or a system requiring additional hardware on shore.

The final system must be:

Boat → Wi-Fi → Android phone

with nothing in between.

Please apply only if you have proven experience with:
- ESP32
- Embedded Wi-Fi
- Long-range 2.4 GHz RF
- External antennas
- Android networking
- Real-time data streaming
- TCP/UDP/WebSocket
- Sonar/fish-finder data is a plus

In your proposal, please explain how you would achieve a reliable 300–400 m direct connection to an Android phone and what hardware you would recommend.