RadioLink F121 Mini Racing Drone User Manual

RadioLink F121 Mini Racing Drone

Product Information

The F121 Mini Racing Drone Altitude Hold by Inertial Navigation is a high- performance drone designed for racing enthusiasts. It is manufactured by RadioLink Electronic Limited, a reputable company in the industry. The drone comes with various accessories and components, including a carrying/shoulder bag for easy transportation, an R8SM receiver, a T8S transmitter for controlling the drone, an FPV camera for real-time video transmission, a 660mAh Li-Po battery forpower, spare propellers, a propeller guard for safety, a propeller removal tool, a Hawkeye 4.3 FPV monitor, a TX and FPV monitor holder, a shell for DIY customization, a hook and spring for  attaching additional equipment, a battery charger, a USB cable for charging and data transfer, RX and FC connect cables, a direction LED for night flight visibility, and a screwdriver for assembly. The package includes the F121 User Manual and the Hawkeye FPV Manual to guide users through setup and operation. The F121 drone features altitude hold capability, which allows it to maintain a stable height during flight using inertial navigation technology. This feature is especially useful for racing and aerial maneuvers.

Product Usage Instructions

1. Power Supply
   • Make sure the transmitter T8S is fully charged before flight.
   • The F121 drone comes with a 1S LiPo battery that is not fully charged by default. Before flight, use the charger CM120 to charge the battery. The CM120 charger is specifically designed for 1S LiPo batteries and ensures safer charging and longer battery lifespan.

For detailed instructions on setup, operation, and safety precautions, refer to the F121 User Manual and the Hawkeye FPV Manual provided in the package. Regularly check the official RadioLink website for any updates to the manuals.

Important safety precautions to remember:

• Do not operate the drone in adverse weather conditions or poor visibility.
• Avoid using the product in crowded or illegal areas.
• Ensure the trim levers of the transmitter are set to 0 and the battery is properly charged before connecting the receiver.
• Maintain a safe distance from the aircraft during flight to avoid injury from high-speed rotating components.
• After landing, make sure the aircraft is disarmed and the propellers have stopped moving before approaching it.
• Always turn off the receiver/power off the aircraft before turning off the transmitter.
• Follow the instructions for propeller installation in case of dropping during flight.
• Choose a flight space without interference like high voltage cables, communication base stations, or launching towers for optimal radio communication.
• This product is not a toy and is not suitable for children under the age of 14. Keep it out of reach of children and exercise caution when operating it in their presence.
• In wet weather conditions, use plastic bags or waterproof cloth to cover the transmitter to prevent water or moisture from entering and causing model instability or loss of control.
• Ensure compliance with FCC Rules and prevent external wireless interference.

Please kindly note that this manual will be updated regularly and please visit RadioLink’s official website to download the latest version：www.radiolink.com

Thank you for purchasing the RadioLink mini racing drone F121.
To fully enjoy the benefits of this product and ensure safety, please read the manual carefully and set up the device as instructed steps. If any problems are found during the operation process, either way, listed below can be used as online technical support.

1.  Send mails to after_service@radiolink.com.cn and we will answer your question at the earliest.
2. Send message to us on our Facebook page or leave comments on our YouTube page
3. If purchased from an approved dealer or distributor, you can contact them directly for support.

All manuals and firmware are available on RadioLink’s official website www.radiolink.com and more tutorials are uploaded. Or follow our Facebook and YouTube homepage to stay tuned with our latest news.

SAFETY PRECAUTIONS

• Never operate models during adverse weather conditions. Poor visibility can cause disorientation and loss of control of the pilot model.
• Never use this product in a crowd or illegal areas.
• Always ensure the trim levers of the transmitter at 0 and the battery is properly charged before connecting the receiver.
• Stay at a certain distance from the aircraft during flight to avoid getting hurt by the components of high-speed rotation (e.g.. Propellers, brushed motors)
• After landing off, make sure the aircraft is disarmed and the propellers have stopped moving before getting close to touching the aircraft.
• Always be sure about turning off the receiver/powering off the aircraft before the transmitter.
• Follow the instructions of propeller installation in case of dropping during the flight.
• To ensure the best radio communication, please enjoy the flight in space without interference such as high voltage cable, communication base station or launching tower.

WARNING

• This product is not a toy and is NOT suitable for children under the age of 14. Adults should keep the product out of the reach of children and exercise caution when operating this product in the presence of children. Water or moisture may enter the mini drone and the transmitter through gaps in electronics and cause model instability, even out of control. If flying in wet weather(such as a game) is inevitable, always use plastic bags or waterproof cloth to cover the transmitter.
• This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: This device may not cause harmful interference and Prevents external wireless interference, including interference that may cause undesired operation.
• Any Changes or modifications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment.

Packing List

Features of F121

• As the mini racing drone that can fly at high speed at Altitude Hold Mode, F121 is very easy to master for drone freshmen. The inertial navigation system technology blending Kalman filtering, gyro, accelerometer, and barometer makes it F121 possible to flight through narrow space with accuracy and hold altitude even if it’s less than one meter height to the surface or at high speed. With three flight modes Alt-Hold at low speed, Alt-Hold at high speed, and Stabilize, beginners can flight stably at the first trial.
• F121 is monitored by RadioLink mini racing drone flight controller F121, which is different from other flight controllers with PIDs that need to be set before use and will tune automatically. The software noise reduction technology not only enables a more pleasant flight but also makes the motors more responsive and more efficient than traditional 8520 coreless motors. It can be thrown and start to fly at any angle even under high speed and remains stable even when faced with sudden airflow fluctuations such as during takeoff, under braking, or after extended flying. Without compass locking, F121 always automatically modifies angles during flight.

Before Flight

Power Supply

• Power for transmitter T8S: Make sure the transmitter is fully charged.
• Power for F121: The voltage of 1S LiPo battery packed with F121 by default is not fully charged so the battery needs to be charged with the charger CM120 before flight.
• The LiPo battery charger CM120, specially designed for 1S LiPo battery, sharing the professional development and high precision of CB86PLUS, ensures safer charging and battery life span.
• Charging current can be set as 1A or 2A by toggling the switch at the side of the charger.
• The Red LED flashes slowly indicating the battery is undercharging. The Green LED always on indicates the battery is fully charged. The Red and Green LED Flashing alternately indicates Fault prompt.
• CM120 applies a general USB connector, both computer and power bank for mobile phones can be used with CM120.
  Note Voltage output of the power supply should be NO higher than 5V.

Transmitter
The two joysticks of T8S correspond to the four basic channels respectively. The below example takes RadioLink radio T8S Mode 2 (Throttle on the left stick) .

Left joystick
Make the F121 rise or descend by toggling the left stick(THROTTLE) vertically upward or downward and turn clockwise or anticlockwise by toggling the left stick(YAW) to the left or right.

Right joystick
Make the F121 fly forward or backward by toggling the right stick(PITCH) vertically upward or downward and to left or right by toggling the right stick(ROLL) to the left or right.

Note If it’s the transmitter from other brands used with RadioLink F121, make sure that the receiver is SBUS signal output supported. Once the receiver is installed on the mini drone, the phase of the throttle should be reversed while the other three channels normal and the CH5 should be set with a 3-way switch. Servo phases of transmitters from other brands should be set according to the actual situation.

F121
Assembled as a building block the RC students exercise their DIY ability and are free from lengthy mobile games.Learning knowledge of science and technology when assembling, setting parameters, and flight.

Joysticks & Flight Movements

• A. Throttle: Rise/ Descend/Hover
  Toggle the throttle stick (on the left) vertically upward and F121 will rise and toggle the throttle vertically downward, then F121 descends.
  If at Alt-Hold Mode, toggle the throttle stick vertically upward till the F121 rises to the preferred height, then toggle back to center position and release, the F121 will remain at this height.

• B. Yaw: Clockwise/Anticlockwise
  Toggle the yaw stick (on the left) to the left and F121 will turn anticlockwise and toggle the yaw stick to the right, then F121 will turn clockwise.

• C. Pitch: Forward/Backward
  Toggle the pitch stick (on the right) vertically upward and F121 will fly forward and toggle the pitch stick vertically downward, then F121 flies backwards.

• D. Roll: Right/Left
  Toggle the roll stick (on the right) to the left and F121 will fly to the left side and toggle the roll stick to the right, then F121 will fly to the right side.

Get Ready to Flight

Motor Installation
To make the aircraft fly, motors usually rotate clockwise(CW)/counterclockwise(CCW) with the propellers. The rotation direction of F121 motors can be identified by the cable colors. That is, red/blue means motor of clockwise(CW) while black/white means that of counterclockwise(CCW). It is very important to make sure about the rotation direction as below when installing motors. Otherwise, the drone would fail to take off.

• Motor installation can be skipped as the whole F121 is already assembled by factory default. If any of the motors is worn out and needs to be replaced, it’s essential to identify the correct motor rotation.

Propellers Installation
F121 is installed WITHOUT propellers protector by factory default because of the package consideration. To ensure a safe flight, it’s strongly advised to check if the protectors are well installed.

1. Find the two notches respectively on the motor protector and propeller protector as image on the right.
2. Put on the propeller protector from the bottom and adjust the position of the notches correspondingly.
3. Stabilize the frame with the left hand and buckle the notch of one side with the right hand. Then buckle the notch of the other side with your left hand. A “DA” sound will be heard if the installation is done with success.
4. Extra 4 screws are in the package and the pilot can install them on the propeller protector as preferred.

Note After the installation of the four propeller protectors, double confirm if they are leaning or slightly shake F121 to see if they drop. If they are crooked or drop, repeat the above steps to ensure the well installation.

• Propellers installation can be skipped as the whole F121 is already assembled by factory default. If the default propellers get worn and need to be replaced after a period of flight, it is important to identify the rotation direction of the propellers. If installed incorrectly, F121 can’t take off even if the throttle is pushed to the max.
• In order to identify the propeller rotation, take a propeller and observe there’s a radian at both sides of the small cylinder in the middle. The higher part (also called the windward side) of the right propeller is at the front and the rotating motor will make the propeller rotate counterclockwise(CCW). On the contrary, that is clockwise(CW) rotation. For the 65mm GEMFAN propellers used on F121, there are two marked with a letter R, meaning they should be installed on the motors clockwise.
• When the installation is done, make sure the four motors are vertical to the aircraft frame. Adjust them to vertical positions if necessary, otherwise, F121 may not fly successfully.

Power On F121
Before powering on F121, fully charge the 1S LiPo battery first. Plug the PH2.0 end of the battery into the F121, then insert the battery into the battery frame at the bottom of the F121.

1. Orange propellers indicate the head of F121 by default. make sure they point in the same direction as the pilot when powering on and be ready to fly, to ensure safety.
2. The green LED of F121 will begin flashing when powered on. When it’s off, it means F121 finishes calibration.

Note Head direction is determinate. If F121 is calibrated with a direction different from the default, it will turn back to the default direction automatically when starts flying, That’s what we call Head Front Forward Point Without Compass. When the flight controller incorrectly recognizes the nose direction, you can re-power the aircraft, or make the flight controller re-identify the nose direction by re-calibrating the aircraft.

Flight Note

• If it’s the first time flying a drone, the flight mode of Altitude Mode-Low Speed is strongly advised to set. At the altitude mode, when toggle the throttle upward till the drone reaches a certain height and release, F121 will remain at this height. It’s simpler because pilots only need to toggle the other joystick to make the F121 move forward/backward or turn left/right. If it’s the Stabilize Mode chosen, try to toggle the joysticks slightly to correct the flight and avoid the drone having sudden moves.
• If F121 drops by hitting something, toggle the throttle stick to the bottom position immediately to stop motor rotation. Make sure the signal output of the receiver is SBUS to ensure normal operation of F121. For RadioLink receivers(R8SM/R6DSM) installed on F121, the LED indicator is blue/purple when it’s SBUS working mode.

Setup Compatible Transmitters
By factory default, the F121 standalone version doesn’t have a receiver installed while the RTF version is packed with the transmitter T8S and receiver R8SM combo. Receiver R8SM is also compatible with RadioLink T8FB. If it’s RadioLink transmitter AT10/AT10II/AT9/AT9S/AT9S Pro used with F121, the compatible receiver should be R6DSM.

When using transmitters and receivers from other brands, please note:

1. Check the minimum working voltage of the receiver.
   The minimum working voltage of many mini receivers on the market can only reach 3.7V, while aircraft with coreless motors are usually powered by 1S 4.2V lithium batteries, and the voltage of the aircraft can easily drop below 3.7V during high-speed flight. Then the receiver will lose control due to insufficient power supply, and the aircraft will crash. So if you use transmitters and receivers from other brands, please pay attention to the minimum working voltage of the receiver. The minimum working voltage of RadioLink R8SM, R8FM, R6DSM mini receivers, and F121 flight controllers can work well even when it reaches 2.3V.

2. Please make sure that the receiver you are using supports the SBUS signal.

T8FB/T8S
RadioLink 8-channel transmitters are well set by factory default with the flight modes. To control F121, binding is the only thing that needs to be done.
There are three flight modes for F121 including Altitude Mode- Low Speed, Altitude Mode- High Speed, and Stabilize Mode. It can be changed by pressing the three-way switch on T8FB- SWB or T8S- CH5 as below

AT9S Pro/AT9S/AT9/AT10/AT10II

1.  Enter BASIC MENU, select MODEL TYPE, and choose MULTIROTOR
2. Return to BASIC MENU, select REVERSE, and set CH3 Throttle as REV .
3. Enter ADVANCE MENU, select ATTITUDE, and set the CHANNEL as CH5, SW3 as SWC with up position as Alt-Hold Mode(Low Speed), a middle position as Alt-Hold Mode(High Speed), and low position as Stabilize Mode.

• For more setting instructions for different RadioLink transmitters, please visit www.radiolink.com to download the corresponding detailed e-manual.

Binding
If it’s the RTF version( whole pack including T8S+F121+bag) purchased, there’s no need to bind because the binding is complete with receiver R8SM installed by factory default. However, if it’s only the aircraft F121 is purchased, binding between the transmitter and F121 with the receiver installed needs to done first.
If fly F121 with RadioLink transmitter and receiver, binding steps are the same as following.

1. Place the transmitter and receiver(installed on F121) close to each other within 50 centimeters.
2. Power on the transmitter and F121.
3. There is a black binding button(ID SET) on the side of the receiver, press it for more than 1 second. When the LED starts flashing, it means binding process has started
4. The binding is complete when the LED is always on.
5. Make sure F121 is armed (Details in next section). Gently push the throttle of the transmitter to see if motors move. If doesn’t, retry binding again.

Note

• F121 currently supports SBUS signal output only, always make sure the LED of R8SM/R6DSM is blue/purple, meaning SBUS signal output. If the LED is red, press the binding button twice in 1 second and release it to change it to purple/blue.
• If it’s the transmitter of AT9S Pro/AT9S/AT10/AT10II used, the channel quantity needs to be set first in order to be compatible with receiver R6DSM. Long press MODE to enter BASICE MENU, select SYSTEM, and modify CH-SELECT as 10CH. Otherwise, F121 won’t be able to be armed.

Arm and Disarm F121

• A. How to arm
  Throttle on left(Mode 2): Toggle the left joystick to the lower right corner and hold this position for 3 seconds till the green LED of F121 is on.

• Throttle on right(Mode 1): With right joystick at bottom, toggle the left stick to the right and hold this position for 3 seconds till the green LED of F121 is on.

B. How to disarm

• When the flight is finished, always make sure F121 is disarmed when get close and try touching it to avoid unexpected harm.

• Throttle on left(Mode 2): Toggle the left joystick to the lower left corner and hold this position for 3 seconds till the green LED of F121 is off.

• Throttle on right(Mode 1): With right joystick at bottom, toggle the left stick to the left and hold this position for 3 seconds till the green LED of F121 is off.

Flight at Different Flight Modes

• It’s strongly advised for beginners to start from Altitude Hold Mode (Low-speed) to Altitude Hold Mode (High-speed) then to Stabilize Mode.
• It’s better to keep the direction of the F121 head the same as the pilot in order to easily judge the flight direction. Otherwise, F121 may fly towards the pilot and get him/her hurt. If the aircraft head is changed unexpectedly and different from the pilot’s direction, pull the throttle stick to the lowest position to land F121.

Altitude Hold Mode (Low-speed) and Altitude Hold Mode (High-speed)
Rise/Descend

• Press the CH5 switch of T8S backward, which makes F121 fly at Altitude Hold Mode (low speed). Make sure the orange propellers at the front when powering F121 on. Then arm F121 and push the throttle joystick vertically upward higher than center position, then the F121 will rise while if push it vertically downward, then the F121 will descend.

Hover

• Push the throttle joystick vertically upward till the F121 rises to a height as wished, then toggle it back to the center position and release, the F121 will hover at this height.

Forward/Backward/Right/Left

• At Altitude Mode, F121 is able to fly forward/backward or towards to right/left by toggling the right stick at a certain height.
• For beginners, make sure to push the stick gently because being a racing drone, the F121 is very responsive. It’s advised to release the stick as soon as toggles to one direction so that F121 will back to level automatically. Otherwise, F121 will keep flying in the toggled direction with accelerated speed.

Clockwise/Anticlockwise Rotation

• When get familiar with the above flights, try flight clockwise/anticlockwise because the yaw practice is more difficult to judge the flight direction. Clearly knowing the direction will quickly help master drone flight. Try imagine sitting on the drone could be a better way to practice.
• Toggle the rudder joystick to the left and the F121 will fly anticlockwise while if to the right, then the F121 will fly clockwise.

Stabilize Mode

• Press the CH5 switch of T8S backward and it keeps F121 working in Stabilize Mode.
• When at Stabilize Mode, F121 will fly faster than when at Altitude Mode. Toggle joysticks as gently as possible to avoid drastic movements, which may possibly hurt the pilot. Make sure that the battery is fully charged before enjoying the flight.
• Once get familiar with the low speed and high speed at the Altitude Mode, beginners can practice how to rise/descend, hover, pitch forward/backward, move to left/right, and rotate to clockwise/anticlockwise at the Stabilize Mode, which is more challenging.

Switch for 360 Angle Flips Mode

• F121 add a mode named Switch for 360 Angle Flips Mode except Altitude Hold Mode and Stabilize Mode. The setting steps as below:

• When the transmitter is T8S, press the CH6 switch twice continuously and then push the aileron or elevator stick. If the aileron sticks to the left, the F121 will roll 360 degrees to the left. If the aileron sticks to the right, the F121 will roll 360 degrees to the right. If the elevator stick is upward, the F121 will roll 360 degrees forward. If the elevator stick is downward, the F121 will roll 360 degrees backward.

• When you are ready to control your F121 roll 360 degrees backward, you must fly your F121 far away from yourself first to ensure safety.

• When the transmitter is T8FB, the 360 Angle Flips Mode switch is VrB, and the operating steps are the same as T8S. Attention: The interval time for pushing the aileron or elevator stick is not more than 5 seconds when you press the 360 Angle Flips Mode Switch. You have to press the switch again if the time is more than 5 seconds.
  Note When the green LED on F121 starts flashing during flight, it means the voltage of F121 is lower than 3.8V as this value is default for 1S battery. It’s advised to stop flying to avoid battery over-discharging.
  If the F121 purchased is with a camera integrated, it’s capable of OSD function and the pilot can check the current voltage of the battery by goggles or FPV screen in real-time.

Image Transmission of F121

• The image transmission device of F121 is a 5.8G 25mW all-channel camera integrated image transmission. If it’s the image transmission version purchased, the binding between F121 and the FPV screen has been done by factory default. Pilots only need to power both on before the flight. If it’s the standalone version of F121, an FPV screen or a goggle with an integrated 5.8G image transmission receiver is needed and set up by following its instructions.
• The default transmission power is 25MW. Available power between 25MW,100MW, and 200MW can be changed by pressing the button on the camera. For more instructions about setting the power, please visit www.radiolink.com for a detailed manual.
  Note As a device of image transmission includes transmit and receive, the distance could be influenced by the gain of transmit and receive.

Little Pilot (SCHOOL) All-in-one 4.3-inch FPV Monitor
Buttons and Functions

Long press to start auto search;

Short press to select desired frequency from 6 groups A-B-C-D-R-F

2. Power/Menu button| Short press to enter menu setting; Long press to turn- on/off
3. Adjustment button(-)| Item decrease;

Short press to select desired frequency from groups 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8

4. Micro USB Charge port| Charging
5. Reset| Reset

Little Pilot Monitor Frequency Group Selection

Bind Little Pilot Monitor to F121

1. Automatic binding (Recommended):
   Power on F121, and then long press the button(+) in Little Pilot FPV to start the auto search. After searching, the FPV screen with the strongest signal will be automatically displayed.

2. Manual binding:

3. Check the frequency of F121 according to the method in Chapter Chapter 5.3.2 Customize the power/Band/Frequency

4. Match frequency of F121 to the frequency table of Little Pilot FPV. Short press button(+) to adjust to the corresponding frequency band, and short press button(-)to adjust to the corresponding frequency point
   For example, the frequency of F121 is B5, 5809, according to the method in Chapter 5.3.2 Customize the power/Band/frequency. 5809 corresponds to D5 in the frequency table of the Little Pilot FPV Monitor. After the FPV monitor is turned on, adjust the band/frequency at the top of the screen to D5 by short- pressing the button(+) and button(-) to complete the binding.

LONGSITE 3-inch FPV Goggle

Description

1. Key 1: Short press for MENU mode; Long press (More than 3 sec) for Power ON/OFF.
2. Key 2: Short press for Auto-Searching (Automatic selection of the strongest channel).
3. Key 3: Short press for Band+ (Change bands A-B-E-F-R circularly).
4. Key 4: Short press for Channel+ (Change channels 1-2-3-4-5-6-7-8 circularly).
5. Eye ring: protect the surrounding parts of the eyes, so that the wear more comfortable.
6. Micro-USB Charging port: Supports DC5V only.
7. Antenna port A: RP-SMA male.
8. Charging indicator: Red light when charging light; full power, the indicator goes off.
9. Antenna port B: RP-SMA male.
10. AV Jack: In RF receiving mode can output AV signal; In AV mode can enter the video signal.
11. Head band: Adjustable headband.

Menu Operation Instructions
In normal mode, press Key 1 to enter the MENU mode.
In MENU mode:

• Key 1: Select the option bar.
• Key 2: Return to normal mode.
• Key 3: Value -.
• Key 4: Value +.

LONGSITE FPV Goggle Frequency Table

Frequency Table(MHz)

 | CH1| CH2| CH3| CH4| CH5| CH6| CH7| CH8
Band A| 5865| 5845| 5825| 5805| 5785| 5765| 5745| 5725
Band B| 5733| 5752| 5771| 5790| 5809| 5828| 5847| 5866
Band E| 5705| 5685| 5665| 5645| 5885| 5905| 5925| 5945
Band F| 5740| 5760| 5780| 5800| 5820| 5840| 5860| 5880
Band R| 5658| 5695| 5732| 5769| 5806| 5843| 5880| 5917

Bind LONGSITE FPV Goggle to F121

1. Automatic binding (Recommended):
   Power on F121, and then long press the Search button in LONGSITE 3-inch FPV Goggle to start the auto search. The successful display of the image transmission means that the binding is successful.

2. Manual binding:

3. Check the frequency of F121 according to the method in Chapter 5.3.2 Customize the power/Band/Frequency

4. Match the frequency of F121 to the frequency table of LONGSITE FPV Goggle. Short press the Band+ button to adjust to the corresponding frequency band, and short press the CH+ button to adjust to the corresponding frequency channel.
   For example, the frequency of F121 is D5, 5820, according to the method in Chapter 5.3.2 Customize the power/Band/frequency. 5809 corresponds to F5 in the frequency table of LONGSITE FPV Goggle. After the FPV goggle is turned on, adjust the frequency at the top of the screen to F5 by short-pressing the Band+ and CH+ buttons to complete the binding.

Image Transmission of F121
LED Indicator of the image transmission

1. RED and BLUE always on means normal working status. YELLOW is used to indicate that the module is overheated, and the image transmission enters the protection mode.
2. If RED is always on while BLUE is off, it means it’s at PitMode. That is, transmission off. The transmission distance is 1-2m. It’s advised to choose this mode if there are many people switching channels simultaneously at the same space so that channels won’t get mixed.
3. The transmission power is 200MW by default. If you need to change the transmission power, press Channels/Power Switching Button on the camera to set it. The transmission power can be set to 25MW, 100MW and 200MW. For details, see Chapter 8.3.2 below.
4. Since the image transmission system consists of the transmit and the receive, the receiving distance of the image transmission is related to the gain of both the transmitter and the receiver of the image transmission.

Customize the power/Band/frequency
After powering on, wait for 10 seconds to initialize, red and blue(and yellow) always on means normal working status. Long press the channels/power switching button, the channel frequency, the channel team and the transmit power will recycle.

*The cover of F121 needs to be removed when pressing the button
Table of Band/Frequency

Frequency Selection : When the image transmission is in a normal working state (that is, when the RED and BLUE indicator lights are always on), long press the channels/power switching button for 5 seconds, and the RED LED flashes once means entering the frequency selection mode. Then short press the button again, the frequency changes each time the button is pressed once. The blue LED flashes 1 time means Frequency 1, 2 times means Frequency 2, 3/4/5/6/7/8, etc.

Take F121 and Little Pilot FPV Monitor as an example:
For frequency selection, long press the channel/power switch button on F121 for 5 seconds to enter the frequency selection mode, and then short press the button to switch to the desired frequency point. For example, the frequency point was originally A1 5865. Short press the channel/power switch button 3 times to switch the frequency point from A1 5865 to A4 5805. After switching the frequency point of F121, the Little Pilot FPV Monitor screen will be disconnected due to different frequency points. At this time, long press the button(+) on the Little Pilot FPV Monitor to start auto search (for the method of manual binding, please refer to chapter: 5.1.3 Bind Little Pilot (SCHOOL) FPV Monitor to F121), After searching, the FPV screen with the strongest signal will be automatically displayed. and the frequency on the screen will be changed to A4 5805 synchronously. After the frequency point is changed, you need to save the settings. Press and hold the channel/power switch button for 3 seconds. The RED and BLUE lights always on indicate that the modified parameters are saved successfully. Otherwise, the original frequency point will remain after F121 is powered on again.

Note : Sometimes the frequency point on the lower left of the FPV screen of the Little Pilot FPV Monitor is different from the frequency point on the upper right, but the image can also be displayed. That is because the image can be seen in a similar frequency band, but once the distance between the aircraft and the FPV display screen is far away, The sensitivity will be reduced, and the image will be unclear, so it is best to keep the same frequency.

Band Selection: In frequency selection mode, long press the channels/power switching button for 5 seconds, and the RED LED flashes twice means entering the band selection mode. Then short press the button again, the band changes each time the button is pressed once. The blue LED flashes 1 time mean Band A, 2 times mean Band B, C/D/E/F, etc.
After F121 and Little Pilot FPV Monitor are successfully bound, if you still need to switch the band, please press the channel/power switch button in the band selection mode to switch to the desired band. After switching, you need to long press the button(+) on Little Pilot FPV Monitor to automatically search for channels. After the band is changed, you need to save the settings. Otherwise, the original band will remain after F121 is powered on again. Press and hold the channel/power switch button for 3 seconds. The RED and BLUE lights always on indicate that the modified parameters are saved successfully.

Power Selection: In Band selection mode, long press the channels/power switching button for 5 seconds, and the RED led flashes three times means entering the power selection mode. Then short press the button again, the power changes each time the button is pressed once. The blue LED flashes 1 time means 25mA, 2 times means 100mW and 3 times means 200mW.
After F121 and Little Pilot FPV Monitor are successfully bound, if you still need to switch the power, short press the channel/power switch button in the power selection mode to switch to the desired power. At the same time, the screen of the Little Pilot FPV Monitor will update the power in real-time. After the power is switched, it will be automatically saved, you don’t need to save the parameters again.
Turn on/off the transmission: When at the normal working status(with RED and BLUE lights on), quickly press the button twice and the working mode will change. When the RED light is on and the BLUE light is off, it means it’s at Pitmode(Low power mode). When RED and BLUE lights are on, it means the normal transmission mode.

Parameter saving : When all parameters are set, press and hold the channel/power switch button for about 3 seconds, the RED and BLUE always on means the setting is saved successfully; the RED and BLUE lights alternately flash means the frequency/band/power selection mode, and the parameters are not saved successfully. You need to press and hold the channel/power switch button again until the red and blue lights are always on.
Note

1. When installing the image transmission camera, make sure the heat radiation is considered. Otherwise, the transmission power will decrease even when turned off as the protection of overheating is activated.

2. It’s normal that the camera will get heated during usage. DO NOT touch it directly with your hands in case of getting burnt.

3. If the transmission antenna is broken or not well welded, the transmission distance will be impacted.
   Replace the antenna as soon as possible.

4. The detailed instructions of setting the FPV screen and goggles, please refer to its corresponding manual.

5. If there’s interference during the usage, try switching the camera channel first, then search for a new channel on the FPV screen or goggles.

T8S Mobile/FPV Monitor Holder Instruction

**** Specifications

• Name: F121(Altitude Hold Micro Racing Drone）
• Weight: 47.5g(Drone only)
• Drone Size: 121*55mm(with antenna; 41mm without antenna）
• Package Size: 170X210x113mm(RTF bag)；210x163x67mm(Standalone box）
• Transmitter Frequency: 2.4G
• Image Transmission Frequency: 5.8G
• Material: Carbon Fiber(Frame), Plastic(Cover, Bases for Image transmission/battery, Prop protector)
• Motor: 8520 coreless with software to reduce noise
• Propeller: GEMFAN propellers with diameter of 65mm
• Transmitter: RadioLink 8-channel handle transmitter T8S
• Receiver: RadioLink 8-channel mini receiver R8SM
• Flight Controller: RadioLink flight controller F121
• Battery: FULLYMAX 3.7V 660mA 25C LiPo Battery
• Charger: USB Charger (1A/2A)
• Flight Time: 10 minutes, suitable for Indoor and outdoor
• Low Voltage Alarm: Green led flashes quickly when lower than 3.8V
• Control Distance: 2KM in the air(Maximum range is tested in an unobstructed area free of interference)

Image Transmission System Specifications

• Operating Frequency: 5.8G(48 channels: 6 brands, 8 channels of each band)
• Power: 25mW/100mW/200mW
• Voltage: DC 3~5.2V (1S)
• Current (4.2V): 320mA(25mW)/400mA(100mW)/460mA(200mW)
• Weight: 4.4g
• Dimensions: 18.0316.8316.55mm
• Resolution: 800 TVL
• FOV: 150°
• Focal Length: 1.2mm

Little Pilot Monitor Specifications

• Brand: Hawkeye
• Frequency: 5.8GHz
• Display Dimensions:4.3 inch
• Resolution: 4803(RGB)272
• Channels: 48 channels
• Brightness: 700 cd/㎡
• Aspect Ratio: 16：9
• Response Time: <10ms
• Color System: PAL/NTSC
• Working Time: more than 2.5 hours
• Receive Sensitivity:-94dB

LONGSITE FPV Goggle Specifications

• Name: Mini FPV Goggles
• LCD Screen size: 3.0 Inch
• Resolution: 480*320
• Display Ratio: 16:9
• View Angle: 6 o’clock
• Brightness: 350cd/m² with high brightness backlight LED
• Video delay: less than 20ms
• Lens: 4X Fresnel Lens, 92% transparent rate no distort of light
• Antenna: 2 X RP-SMA male
• Languages: English and Chinese
• Power adapter: DC5V/1A (USB interface)
• Battery: 3.7V/1200mAh, Each full charge revive around 2.5hr working time

Thank you again for choosing RadioLink products.

References

• RadioLink 乐迪电子-官方网站

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