Tutorial on Setting Up a 6-Position Switch with RadioLink AT10 Transmitter and APM Flight Controller



RadioLink AT10 is a 10‑channel professional RC transmitter launched by Shenzhen RadioLink Electronic Co., Ltd. It features a well‑arranged switch and knob layout, easy operation, and simple programming. Its Chinese menu is user‑friendly for domestic users, and it also supports data feedback. Targeted at professional users, the AT10’s most important feature is its unique curve mixing function, which enables simple, intuitive setup of six flight modes using one 2‑position switch and one 3‑position switch. For these reasons, the AT10 is highly recommended for use with APM flight controllers.

First, understand the flight mode switching principle of the APM. The APM supports multiple flight modes, but only six can be assigned at a time. These six modes are controlled by Channel 5 (Channel 8 for fixed‑wing aircraft). Unlike conventional RC switches that output low/medium/high signals, the APM identifies modes by reading PWM pulse width ranges from the receiver. The six ranges (unit: μs) are:

0–1230, 1231–1360, 1361–1490, 1491–1620, 1621–1749, 1750+.

A PWM value within each range triggers one flight mode. To prevent accidental mode switching caused by signal drift near thresholds during flight, use these optimal mid‑range values: 1165, 1295, 1425, 1555, 1685, 1815.

This guide explains how to configure these six precise PWM values using the RadioLink AT10.

I. Basic Transmitter Configuration

Before setting the 6‑position switch for APM, complete these three basic settings on the transmitter:

  1. Set model type to Fixed‑Wing (required regardless of APM firmware, even for helicopters; ensures independent channel output).
  2. Assign switches to channels.
  3. Set channel phase (reverse).

Detailed steps below:

1. Set Model Type to Fixed‑Wing

  1. Power on the transmitter. Long‑press the MODE key to enter the Basic Menu.
  2. Navigate to System Settings using the navigation keys, then press the PUSH key to enter.
  3. Navigate to Model Type, rotate the PUSH knob to select Fixed‑Wing Model.
  4. Long‑press the PUSH key. When “Confirm Change?” appears, press the PUSH key again. After hearing several beeps, the model type will switch to Fixed‑Wing.

2. Assign Switches to Channels

  1. In the Basic Menu, navigate to Auxiliary Channel Function and press PUSH to enter.
  2. Select Channel 5, rotate the dial to choose SwC, then press PUSH to confirm the switch assignment.

3. Set Channel Phase

  1. In the Basic Menu, navigate to Servo Phase and press PUSH to enter.
  2. Set Channel 5 phase to Normal (positive).

II. Six‑Mode Setup with Two Switches

After completing the basic settings, prepare the hardware: Connect the receiver, APM flight controller, and computer; bind the transmitter and receiver.

Open Mission Planner (MP) → Initial Setup → Flight Modes to monitor real‑time PWM output and mode switching status.

1. Setup Logic

We use curve mixing with:

  1. 2‑position Switch B: Enables/disables mixing.
  2. 3‑position Switch C: Selects mode groups.

Core Logic

  1. Switch B = UP (no mixing): Three modes (Mode 1, 4, 6) set via servo travel and subtrim to match optimal PWM values.
  2. Switch B = DOWN (mixing enabled): Three additional modes (Mode 2, 3, 5) set via curve mixing points 1/3/5 to match optimal PWM values.

Switch & Mode Mapping

  1. B(UP)+C(UP) → Flight Mode 1
  2. B(UP)+C(CENTER) → Flight Mode 4
  3. B(UP)+C(DOWN) → Flight Mode 6
  4. B(DOWN)+C(UP) → Flight Mode 2
  5. B(DOWN)+C(CENTER) → Flight Mode 3
  6. B(DOWN)+C(DOWN) → Flight Mode 5

2. Step‑by‑Step Setup

2.1 Configure Mode 1, 4, 6

  1. Power on the transmitter. Long‑press MODE → Basic Menu; short‑press MODE → Advanced Menu.
  2. Navigate to Programmable Mixing → Curve Mix 5 and press PUSH to enter.
  3. Set Subtrim for Mode 4 (1550 μs)
  4. Set Switch B = UP, Switch C = CENTER.
  5. Go to Basic Menu → Subtrim → Channel 5 (Gain).
  6. Adjust the subtrim while monitoring MP until PWM = 1550 μs (subtrim value: +46).
  7. Set Servo Travel for Mode 1 & 6
  8. Go to Basic Menu → Servo Travel and press PUSH.
  9. Mode 1 (1164 μs): Set B=UP, C=UP. Adjust travel until PWM = 1164 μs (travel: 75%).
  10. Mode 6 (1815 μs): Set B=UP, C=DOWN. Adjust travel until PWM = 1815 μs (travel: 48%).

2.2 Configure Mode 2, 3, 5

  1. Go to Advanced Menu → Programmable Mixing → Curve Mix 5 and press PUSH.
  2. Mode 2 (1295 μs)
  3. Set B=DOWN (mix on), C=UP. Navigate to Point 1.
  4. Adjust the value while monitoring MP until PWM = 1295 μs (ratio: ‑32%).
  5. Mode 3 (1425 μs)
  6. Set C=CENTER. Navigate to Point 3.
  7. Adjust the value until PWM = 1425 μs (ratio: +37%).
  8. Mode 5 (1685 μs)
  9. Set C=DOWN. Navigate to Point 5.
  10. Adjust the value until PWM = 1685 μs (ratio: +50%).
  11. Smooth Transition: Set Point 2 and Point 4 for linear interpolation between Point 1–3 and Point 3–5.

With these settings, the RadioLink AT10 is fully configured for six flight modes with the APM flight controller.