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Retro Edition MkII

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Linar Yusupov edited this page Jun 26, 2026 · 63 revisions



Retro Edition Mark II is a successor of SoftRF Retro Edition.

The Mark II uses the same STMicroelectronics® MCU ( STM32F103 ) that older Retro Edition does. The STM32F103 microcontroller was very popular between 2010 and 2020. That's why we call the design as Retro.

The Retro MkII is based on third-party's hardware - Ebyte® E80-900MBL-02 product, which is available for direct purchase from manufacturer at more or less reasonable price ( 10+ USD ).

Ebyte® E80-900MBL-02 uses the most recent and advanced Semtech LR2021 multi-band radio on the market



Compatibility 1

Type Protocol FLARM OGN tracker PilotAware Skytraxx SoftRF
Radio FLARM AIR V7

 

1090 ES
ADS-B

2
Data FLARM NMEA

  Garmin GDL90

 

Dump1090  

1 - it is necessary for a reader to distinguish the difference between statement "compatible" and statement "fully compatible".
     SoftRF implements only a reasonable minimum of the protocols specs. No "bells and whistles" so far.
2 - Reception of DF17 traffic 'downlink' frames only.

Important

Ebyte® E80-900MBL-02 has very limited internal flash memory space - 128K bytes only.
Due to this constraint, default build of SoftRF firmware binary for Retro Mark II includes

  • 1090ES ( ADS-B @ 1090 MHz ) and
  • Legacy ( AIR V7 )

radio protocols only.
Users who need other protocols should build a custom firmware from source code.

Warning

For the Legacy ( AIR V7 ) radio protocol to function properly it is required to connect the Retro Mk.II board with

  • ( NMEA ) GNSS module or
  • ( MAVLINK ) UAV autopilot

ADS-B Out remark

No doubts that an amateur-built non-certified low-cost ADS-B transponder is possible.
It was shown to public by our own "proof-of-concept" study for :

However, as a certified and instrument rated pilot with 20+ years of experience, in no way I will give a tool for every looser in the world, all he/she can afford is to spend 10 USD for the Ebyte® E80-900MBL-02, to abuse the ADS-B technology and compromise my own flight safety and flight safety of every other air law abiding pilot.

SoftRF firmware does intentionally exclude every possibilities to transmit anything on 1090 MHz radio frequency.
Any attempt to contribute the transmit feature into SoftRF from aside will be blocked at very early stage.


Comparison

Edition Retro ES Nano  Retro Mk.II 
Picture
First appearance 2019 2022 2025 2026
Manufacturer you Great
Scott
Gadgets		 RadioMaster
RC		 Ebyte
SoC STMicro
STM32F103		 NXP
LPC4320		 Espressif
ESP32-C3		 STMicro
STM32F103
sub-1GHz radio Semtech
SX1276		 Maxim
Integrated
MAX2837 and
MAX5864		 Semtech
LR1121  		Semtech
LR2021 
Protocols AIR V6
OGNTP
FANET
P3I		 ADS-B  AIR V7
OGNTP
FANET
P3I
ADS-L  		ADS-B 
AIR V7
Wi-Fi 2.4 GHz
802.11bgn
USB 2.0 device 2.0 device CH340
USB to UART

Summary

New Retro Edition Mark II

  • uses the same SoC as Retro Edition ;
  • can receive ADS-B traffic @ 1090 MHz like ES Edition does ;
  • compact enough to operate together with a UAV autopilot. This makes the device to be a good ADS-B receive add-on for Nano Edition

Use cases

Basic

Follow these instructions to install SoftRF firmware binary into your Retro Edition Mark II.

The minimum list of hardware to start using the Retro Mk.II is:

  • Ebyte E80-900MBL-02 ;
  • USB OTG cable for your smartphone ;
  • 1090 MHz antenna

Default setting is to output air traffic over USB in Garmin GDL90 data format.

One can see GDL90 "Heartbeat" message on this screenshot right after completion of the boot sequence:



Important

Be aware, that when a GNSS module is not connected to Ebyte E80-900MBL - the SoftRF is unable to supply GDL90 OwnShip Location Report message. Your EFB software should use some other GNSS source to locate itself.


This is an example of settings for Avare application


Wireless

When USB connection to EFB software is unwise or impossible - one can use this LilyGO® T-Dongle as a bridge from USB into Wi-Fi:

This Espressif ESP32-S2 SoC based device contains a Type-A connector that can operate in USB-OTG mode:

When LilyGO® T-Dongle is driven by SoftRF WebTop USB firmware - it takes GDL90 messages from Retro Mk.II over USB, then transfers the data through Wi-Fi to a connected EFB software client, such as Avare application:

 



UAV

Ebyte® E80-900MBL-02 does not have any of 5V power pins exposed to the header(s).
You need to solder this pin by yourself.




Put a jumper between GND and PC13 pins in order to enforce the Retro Mk.II device to enter into UAV mode on every boot.




Apply the following wiring scheme

Autopilot
TELEM2		 Ebyte® E80-900MBL-02
VCC 5V
TX (OUT) PB11
RX (IN) DIO7 (PB10)
GND GND

One can use this picture as an example.


Data protocol Baud rate
MAVLink 1.0 57600

Important

In order to succeed, your autopilot (AP) has to be configured in Mission Planner as explained on this page:
http://ardupilot.org/copter/docs/common-ads-b-receiver.html#setup-through-the-ground-station

From AP to SoftRF

Required

MAVLINK_MSG_ID_HEARTBEAT
MAVLINK_MSG_ID_SYSTEM_TIME - accurate GNSS time for Air V7 / ADS-L / OGNTP frequency hopping
MAVLINK_MSG_ID_GPS_RAW_INT - own aircraft position

Recommended

MAVLINK_MSG_ID_SYS_STATUS - AP battery charge level
MAVLINK_MSG_ID_VFR_HUD - barometric altitude
MAVLINK_MSG_ID_ATTITUDE - pitch, roll, yaw
MAVLINK_MSG_ID_ADSB_VEHICLE - traffic from other connected ADS-B receivers (if any)

From SoftRF to AP

MAVLINK_MSG_ID_ADSB_VEHICLE - air traffic received by SoftRF sub-1GHz radio
request for MAV_DATA_STREAM_EXTENDED_STATUS
request for MAV_DATA_STREAM_EXTRA3


When a signal is received from local air traffic, a corresponding icon is displayed in the Mission Planner:



Live air traffic map

The Retro Mark II can supply data to private or public Live Traffic resources.
Most widely used data format for this purpose is D1090, also known as AVR or "raw ADS-B".

One needs to change the device settings to select D1090 as data output format.
Next boot of the Retro Mk.II produces the following output over USB



This is an example of instructions for Raspberry Pi

Server

$ dump1090 --net-only --interactive

Feed

$ stty -F /dev/ttyUSB0 38400 raw
$ cat /dev/ttyUSB0 | tee log.txt | nc -N localhost 30001

This is how Live Traffic Map looks in a web browser


Disclaimer

SoftRF firmware for Retro Edition Mark II is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

In general a lot of Chinese DIY electronics manufacturers are known to behave this way:

  • sometimes they may not apply necessary Q.C. before releasing of a product from factory ;
  • they may arbitrary change schematics and electronic components from one batch to the next one.

Author of SoftRF firmware:

  • will reject any hardware related claims associated with Ebyte® E80-900MBL-02 product. Ask for support from seller or manufacturer ;
  • reserves the right to suspend or terminate support of Ebyte® E80-900MBL-02 in the firmware at any time.

For the time being ( June'26 ) there were no critical hardware issues reported for current version of the Ebyte E80 product. However things my change over the time...
If you have issues with bringing up your new Ebyte® E80-900MBL-02 or just not happy with the product - be prepared to execute your Purchase Protection plan.

Bill of materials

Required

Number Part Qty Picture Source
1 Ebyte® E80-900MBL-02 1 Ebyte Store
AliExpress

Important

Make sure that you are ordering -02 variant of Ebyte® E80-900MBL device.
Earlier made -01 variant uses previous Semtech LR1121 radio which is not able to receive ADS-B @ 1090 MHz. Driver for LR1121 radio is NOT included into SoftRF firmware for Retro Edition MkII.


Recommended

Number Part Qty Picture Source
2 Antenna
1090 MHz		 1 TBD
3 Test Stand PCB Clip 2.54mm Spacing 1 AliExpress
4A ST-LINK V2 adapter 1 AliExpress
4B DAPLink adapter 1 AliExpress

Settings

Procedure of settings change is explained here.
Settings description is located there.

Important

Default build of SoftRF firmware binary for Retro Mark II includes

  • 1090ES (ADS-B @ 1090 MHz) and
  • Legacy (AIR V7)

radio protocols only.

If you are an application developer and you think about to add the Retro configuration menu into your software, please, use:

Default settings

Protocol Aircraft type
1090ES (ADS-B) Glider

Important

Default radio protocol setting for the Retro Edition Mk.II is ADS-B.
However, most of other SoftRF devices use OGNTP protocol as the default one.
Devices can "see" each other when they operate on the same radio protocol only !


Antennas


915 MHz and 2.4 GHz antennas that come with the Ebyte® E80-900MBL-02 are quite good for their original purpose.

 


However, an ADS-B antenna ( purchased separately ) performs much better for the 1090 MHz band.


LEDs

  • steady red PWR LED indicates unit power on status ;
  • blue LED1 blinks when the Retro MkII transmits a radio packet ;
  • blue LED2 blinks when device receives a radio packet.

Power consumption

Average current from 5 Volt source is 50 mA.

Enclosure

When a basic cover from moisture, grease and dust is sufficient for you - it is quite typical to use a heat shrink tube for this purpose. Matching diameter of the tube for Ebyte E80 board is 35-40 mm.

This is an example of Dongle Edition - Retro will have a quite similar look.


Optional equipment

SoftRF WebTop USB (USB to Wi-Fi adapter)



Additional information on E80 900MBL-02

  1. Ebyte® E80-900MBL-02 User Manual
  2. Ebyte® E80-900MBL-02 Schematics
  3. Ebyte® E80-900MBL-02 Demo
  4. Ebyte® E80-900M2212S module User Manual

Hardware

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