How To Set Up and Wire the TBS Crossfire Nano Diversity Rx

If you want to fly longer range with Crossfire then the TBS Crossfire Nano Diversity is likely to be the most ideal choice of receiver.

The setup is similar to that of the TBS Nano receiver, however there are a few extra things to consider due to the additional features that come with Team Black Sheep’s diversity offering.

If you are using TBS Nano Receiver, check out this guide instead.

The TBS Nano Diversity is a fully featured TBS Diversity receiver, including the ability to make use of a backup battery in the event of battery ejection. Awesome!

If you are just looking for a quick reference wiring diagram / pinout to aid you with a build, check out the wiring overview.

Prerequisite

This guide aims to help you understand some of the many various configuration options available for the TBS Nano Diversity receiver.

You will need a TBS Nano Diversity receiver and one of the compatible Crossfire transmitter modules.

We will assume that if you are reading this, you are likely already using TBS Crossfire and have a good understand about what it is.

Whether you are new to the TBS Crossfire ecosphere or you already have a good understanding, there is some good information here worth checking out too!

TBS Nano Diversity Receiver Wiring Overview

The following reference diagrams are for the TBS Nano Diversity receiver and aim to provide a clear reference to assist in your build.

You can also consult the TBS Crossfire manual and TBS Nano Diversity quickstart guide for further information.

TBS Nano Diversity Pinout

The following diagram shows the pinout for the TBS Nano Diversity. It shows the available functions for each pin.

This diagram is designed to be used as an easy reference when wiring the receiver. Some functions are duplicated and in these cases you can choose whatever pin you prefer to use.

TBS Nano Diversity Channel Mapping

The following table shows the various functions that are available for each channel on the TBS Nano Diversity receiver.

In order to choose the function that you want to operate on a particular pin, use the channel mapping menu accessible from your TBS Crossfire transmitter module (either Lua script or OLED display on the full sized Crossfire).

You can sort the table by clicking the column headers. For example if you wish to connect CRSF Tx, simply click the header to sort the table and show all suitable pins at the top.

You can also scroll the table left and right to reveal all of the functions. The table shows which functions are compatible with each pin.

TBS Nano Diversity Typical Wiring Diagram

The following diagram shows typical wiring between TBS Nano Diversity Rx, a flight controller and TBS Pro Nano video transmitter.

CRSF and Video Transmitters (TBS Fusion)

If you are planning to use a TBS video transmitter (VTx), such as the Unify Pro Nano shown in the diagram, you have two options for wiring:

• CRSF Tx and CRSF Rx from the VTx can be wired to a spare UART (serial port) on the flight controller. This allows data to be passed between the Unify and Crossfire system via the flight controller.
• CRSF Tx and CRSF Rx can be wired directly to an additional UART on the TBS Nano Diversity receiver for direct communication between the receiver and the VTx (shown above with the dotted line).

When your TBS gear onboard the drone is connected using the CRSF, it allows for some awesome additional functionality.

For example, if you are using TBS Fusion as your video receiver (VRx) then it is possible to use CRSF to synchronize the video settings automatically between the VTx and VRx.

TBS Nano Diversity Backup Battery

Unlike the smaller TBS Nano receiver, the TBS Nano Diversity receiver can be connected to a backup battery.

There is a special pin for connecting the battery and TBS Nano Diversity will automatically charge the backup battery from the main pack when connected.

What does the backup battery in TBS Nano Diversity do?

If the TBS Nano Diversity is connected to a backup battery it will remain switched on in the event of losing power after a crash, such as if the main battery is ejected.

This allows the TBS Nano Diversity receiver to function as a beacon in order to aid recovery of the drone.

TBS Nano Diversity receiver can also reconnect to the TBS Crossfire transmitter and send crash site GPS coordinates.

If the telemetry connection was lost before the crash, for example as you came down behind a mountain, the GPS coordinates that you have may not be accurate.

However if you travel to this position it is a lot more likely that your Crossfire system will be able to establish a connection and provide your transmitter module with an updated set of GPS coordinates of the actual crash site.

Crossfire will perform these crucial functions with or without a backup battery and with any of the available receiver modules.

What Battery should I Use for the TBS Nano Diversity Receiver?

There are some limitation as to what battery can be used for the backup battery. The TBS Nano Diversity does not have the ability to prevent over discharge.

Therefore it is important that the backup battery pin must be connected to a 1S Lipo battery which features a built in battery management system (BMS).

This type of 1S Lipo is readily available and is often used in small rechargeable electronic devices.

TBS Nano Diversity will automatically charge the backup battery when powered from the main battery.

This is a very cool feature to have for those wanting to fly longer range and in general when there is a greater risk of loss.

Diversity Antenna Configuration

Another primary feature of the Nano Diversity receiver when compared with the standard nano receiver is the inclusion of a second radio chip.

Unlike the standard Nano receiver which has a single radio chip connected to its onboard microcontroller, the Nano Diversity actually has two radio transceiver chips.

This allows us to connect two different antenna to the receiver, one to each of the onboard radio chips.

This gives the Diversity Nano receiver the ability to communicate with the Crossfire transmitter on the ground using either of its antenna.

Antenna diversity is not just used in FPV, it can be found in many different areas that utilize radio communications. Check out this Wikipedia article for a little further information if you are interested.

How To Mount TBS Nano Diversity Antenna on an FPV drone

Having the option to use two antenna on our quad allows us to overcome some of the shortcomings of a single antenna solution.

There are two approaches that I see being used for FPV drones, each giving a slightly different benefit.

Polarisation Diversity

Antennas mounted on FPV drones are always omni-directional so that the signal is received as evenly as possible no matter the orientation of the drone.

However in practice an omni-directional antenna does not receive or transmit a signal in a completely even sphere.

It’s pattern of sensitivity is more of a donut around its axis with a dead spot above and below it.

This means that as you bank your drone over, the moment the antenna is pointing directly at your radio it will lose signal if you are a certain distance away.

Polarisation diversity involves taking two antennas and mounting them orthogonally so that the dead spot of one antenna is covered by the coverage of the other and vice versa.

When using TBS Diversity Nano with two orthogonally positioned antenna, if you bank over so that the dead spot of one antenna is pointing at your radio, the other antenna at 90 degrees will have a good connection.

In this case the receiver will automatically switch to the best antenna RSSI and the connection will not be lost.

This type of antenna placement would be well suited to longer range freestyle type builds.

Anyone wishing to perform freestyle maneuvers at distance or with poor line of sight could consider mounting two Immortal-T antenna orthogonally.

Eliminating black spots

Another type of problem that can occur with FPV radio links is the drone itself causing a loss of line of sight. This can be more of a problem for larger drones.

If your drone banks over and the actual chassis of the drone blocks line of sight to the radio, it can cause loss of radio link.

Like with the problem of polarisation, the problem of black spotting can become more pronounced at a greater range.

Mounting a pair of matching antenna on opposing sides of the drone, such as at the very front and back, means that black spots from the chassis itself can be eliminated.

Ultra long range builds using 7-inch frames or larger will benefit from a BardPole in the same polarization mounted to the front and back of the drone.

This will ensure a rock solid link whether travelling towards or away from oneself.

Orthogonal placement maybe not so much a concern in this case as those looking to prioritise range are not likely to fly in a straight line and won’t be performing so many acrobatic maneuvers.

External References

• TBS Crossfire Manual: https://www.team-blacksheep.com/tbs-crossfire-manual.pdf
• TBS Nano Diversity quickstart: https://www.team-blacksheep.com/tbs-crossfire-diversity-nano-quickstart.pdf
• 1S backup battery with BMS on Amazon [affiliate link]: https://amzn.to/3ABYKvV
• TBS Nano Diversity on Amazon [affiliate link]: https://amzn.to/3axJA0b
• Ultimate TBS Crossfire FAQ: https://noirfpv.com/tbs-crossfire-faq/