• Compatibility
• Comparison with Prime Mark II
• Certificates
• ADS-B Out remark
• Use cases
  • Receiver
  • Bridge
  • Solo
• Hardware dependencies
• Known limitations
• Disclaimer
• Bill of materials
  • Required
  • GNSS
  • Battery
  • Recommended
• Wiring
  • Receiver
  • Bridge
  • Solo
• Periphery connections
• Firmware
• Antenna
• Enclosure
• Battery life
• Optional equipment

Uni Edition has taken it's name as an abbreviation of "Universal Access Transceiver" (UAT), which is one of ADS-B standards that operates at 978 MHz aviation radio band. Despite "transceiver" word being used in previous sentence, this particular SoftRF device does NOT transmit anything on the 978 MHz band (dedicated for certified aviation equipment). Only receiving capabilities of the device are in use.

ATTENTION ! Purpose of this SoftRF Edition is NOT for new users! Instead, Badge, Prime Mk II or Dongle Editions are recommended for you to start with.
Uni Edition is for those of current SoftRF users who already familiar with other devices and ready to spend own time and efforts to evaluate if unique UAT ADS-B reception feature works appropriately for his or her needs.

Uni Edition is based on third-party's hardware - TI SensorTag LPSTK-CC1352R development kit, which is available for direct purchase from manufacturer at more or less reasonable price - 30 USD _{(plus shipping)}.

Type	Protocol	FLARM	OGN tracker	PilotAware	Skytraxx	SoftRF
Radio	UAT 978 ADS-B					2
	FLARM AIR V6
	OGNTP
	P3I
	FANET+					3
	SRD 860 ADS-L
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 traffic 'downlink' frames only ;
³ - valid for Uni Edition with optional SoftRF LoRa module.

These are key features to distinguish Uni from other SoftRF Editions :

• UAT (ADS-B 978 MHz) reception and decoding is it's built-in functionality ;
• TI Sensortag is FCC, CE and IC certified equipment ;
• it is manufactured and distributed by world famous Texas Instruments brand ;
• LPSTK-CC1352R is a retail product that comes with a nice, factory made enclosure ;
• it is designed to be powered by hazard-free AAA battery cells ;
• easy to install or revert device firmware by means of Bluetooth LE OAD smartphone app.

However, there are few features missing, such as :

• it does not have a built-in GNSS receiver ;
• no built-in Wi-Fi nor 'classic' Bluetooth ;
• unable to operate with FANET protocol (it uses LoRa modulation) 'out-of-the-box' .

TI SensorTag has the following certificates of compliance :

• (EU) CE Declaration of Conformity
• (US) FCC ID : Z64-LPSTKCC1352R
• (Canada) IC ID : 451I-LPSTKCC1352R

It means that this device is approved by corresponding agencies for:

• land use and
• with genuine factory firmware only.

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 :

• 1090 ES ("ADSB-Out" GitHub project) in 2017, and
• 978 UAT ("UAT-test-signal" GitHub project) in 2018 .

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 30 USD for the TI SensorTag, 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 978 MHz radio frequency.
Any attempt to contribute the transmit feature into SoftRF from aside will be blocked at very early stage.

UAT Receiver makes reception of UAT signals, then transmits serial data frames over UART @ 2 Mbps.
This data rate and format of the frames were choosen to be compatible with Stratux UATRadio, Low Power v3.

Receiver function is better explained on a separate page.

Purpose of the UAT bridge is to receive ADS-B traffic information on UAT (978 MHz) aviation frequency,
then to re-broadcast the data using one of supported RF ISM band protocols.

Bridge function is better explained on a separate page.

We assume that you are already familiar with Dongle and Prime Mk II Editions.
In Solo use case the Uni is operating exactly the same way as other Editions do:

Radio	UAT	Air V6	OGNTP	P3I	FANET+
Receive					4
Transmit					4

⁴ - valid for Uni Edition with optional SoftRF LoRa module.

Data	Stratux	NMEA	GDL90	Dump1090
Input
Output

Procedure of settings change is similar to that the Dongle has.
Settings description is located here.

Firmware variant	USB to Serial adapter	GNSS module	Pressure sensor	OLED display	Wi-Fi or BT or BLE adapter
Receiver	Required	Not required	Not required	Not required	Not required
Bridge	Required 5	Highly recommended 6	Recommended	Not required	Not required
Solo	Required 5	Required	Recommended	Recommended	Recommended

⁵ - 'USB to Serial adapter' is in use by Bridge and Solo variants for the purpose of troubleshooting and settings change only ;
⁶ - bridging of UAT traffic into "Air V6" radio protocol needs accurate timing and true own position data to operate properly. It will NOT function in '"Air V6" option without a GNSS source. OGNTP, P3I and (optional) FANET bridging should be fine (in EU region) without GNSS.

1. reception of UAT signals is currently limited to "downlink" (air-to-air) packets only. So, realtime weather and other "bells and whistles" of the UAT protocol are not available ;
2. "Stock" TI SensorTag has built-in passive HF filter to meet FCC compliance. Because of that, sensitivity @ 978 MHz is a bit reduced.

SoftRF firmware for Uni Edition 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.

Author of SoftRF firmware:

• will reject any hardware related claims associated with TI SensorTag development kit. Ask for support from seller or manufacturer ;
• reserves the right to suspend or terminate support of TI SensorTag in the firmware at any time.

For the time being ( July '20 ) there were no critical hardware issues reported for current version of the SensorTag kit. However things my change over the time...
If you have issues with bringing up your new TI SensorTag or just not happy with the board - be prepared to execute your Purchase Protection plan.

Number	Part	Qty	Picture	Source
1	TI SensorTag LPSTK-CC1352R	1		TI Store
2	CP2102 USB 2.0 to TTL UART serial converter	1		AliExpress

Number	Part	Qty	Picture	Source
1	'noname' NEO-6M GPS module	1		AliExpress

This GNSS module is one of the most basic ones that is known to work good enough.
However, you may consider to read this guide while looking for an alternative.

AAA Ni-Zn (1.6 Volts) is the only battery type applicable for Uni Edition.
It is recommended to purchase an appropriate Ni-Zn charger as well.

Number	Part	Qty	Picture	Source
1	AAA Ni-Zn battery cell	4		AliExpress

Number	Part	Qty	Picture	Source
1	TTGO 0.96" I2C OLED display	1		AliExpress
2	Bosch BMP280 pressure sensor	1		AliExpress
3	Bluetooth HC-05	1		AliExpress
4	Serial WiFi v1.0	1		AliExpress 1 2 3 4 5
5	Antenna 868 MHz 7	1		EBay AliExpress 1 2

⁷ - 868 MHz variant is applicable for these world regions: EU, RU, NZ, SA, IN ;
     915 MHz - US, CA, AU, IL, KR ;
     433 MHz - CN .

This use case needs no changes to be applied to the SensorTag's PCB.

It is recommended to solder a wire between pins 21 and 1 of SensorTag's pin header in order to supply 3.3 Volts power to a GNSS module.

Solder additional power supply and ground wires in accordance with this illustration:

Type	Thumbnail	Details
Serial		Full picture
USB		Full picture
Bluetooth		Full picture
I2C		Full picture
OLED		Full picture
Sensor		Full picture

Depending on your use case, you need to choose an appropriate file from Receiver, Bridge or Solo SoftRF firmware binaries.

SoftRF firmware installation and update is performed by Bluetooth Low Energy "over-air-download" (OAD) method from a smartphone/tablet with Simplelink SensorTag (Android) or TI SensorTag (iOS) application.

For details, please, read this page.

Sensortag's 'stock' antenna is definitely NOT the best one for 868-915 MHz band:

It is Ok to begin with but it makes sense to further transit onto a better one.
Depending on your geo location and protocol preference you may think about to use a dedicated 868, 915 or 978 MHz antenna from a trustworthy source.

TI Sensortag comes with nice molded plastic case and rubber-like dust cover :

However, if you need more space for your external hardware options - please, consider to use 3D design of 'Sleeve' extension for the SensorTag enclosure :

STL files of this enclosure are available. For details, please, read this page.

Major power consuming component of the Uni Edition is a GNSS module being used.
Below are measurements have been taken with ublox 8 based GG-1802 GNSS module :

GNSS	Not connected	Acquisition Mode	Power Save Mode
Avg. current	10-15 mA	50-60 mA	25-35 mA

Operating time from a full charge depends on your actual battery capacity.

SkyView EZ is a DIY companion device for SoftRF Uni Edition.