Jumper T16 Pro - is it ready for prime time?

The launch of the Jumper T16 has attracted a lot of attention. It's well equipped, runs OpenTx, and is very aggressively priced. But is it good enough for high value sailplanes? Could it replace my FrSky X9D Plus?

There was only one way to find out, which was to get one and play with it!

A bit of background: for the last six years I've used a FrSky X9D and X9D Plus for all my flying, including F3F competition. These radios have proved to be excellent workhorses - reliable and easy to manage. For sure, the T16 Pro would have to be seriously good to replace them! Does it hit the mark? Read on!

Overview

Although they look quite different, the T16’s specification is strikingly similar to the FrSky X10 - switch layouts are the same, the screens appear identical, and they run almost identical variants of OpenTx.

T16 has a same similar spec to X10, but adds an MPM

The main differentiator is the T16's multiprotocol module (MPM). This supports more than 50 protocols including ACCST/D16/D8, DSM2, DSMX and HOTT. The module is internal in the 'Pro' version, leaving the external bay free for an additional JR-style module.

Of course the question is: do you need 50 reverse engineered protocols? Only you can decide! But as we'll see, it's really rather clever, especially for FrSky users.

Operating system

My T16 Pro came with JumperTX, a quick and dirty fork of OpenTx 2.2. What I didn't know was that JumperTX is not compatible with OpenTX Companion. This meant that the T16 Pro was effectively useless, as I could not transfer my existing models from the X9D+ except by typing them directly into the transmitter. The prospect of wearing out my fingers didn't appeal, so I put the new transmitter to one side.

A few weeks later, the T16 gained official OpenTX support which meant that I was finally able to get up and running. Woohoo - all my models and Lua scripts work fine in the their new home!

New units will come with OpenTX preinstalled.

It works! My F3F setup with adaptive trim script under OTX 2.3.2. Bubbles are from screen protector (my fault!).

Flashing the multi-protocol module (MPM)

With OpenTx installed and running, my attention turned to the MPM.  This is an open source project by Pascal Langer and the design is well proven in products such as the iRangeX.

The first task was to install the latest MPM firmware. Normally this would be done by copying the firmware to the SD card and flashing from OpenTX, however my MPM didn't have a bootloader which meant that I had to flash the MPM using a USB to serial adapter. The procedure is well described here (thanks Benzo99) and I had no problems.

A bootloader was installed as part of the process (future MPMs will be shipped with the bootloader pre-installed).

Using the MPM with FrSky ACCST

Many users will want to pair the T16 Pro with their FrSky receivers. One really nice feature is that both EU and non-EU receivers are supported, and I had no problems binding to an X8R and RX6R (both non-EU), and a G-RX6 (EU-LBT). All worked fine, including telemetry. Note however that while the MPM understands the LBT protocol, it doesn't actually listen before talking. Neither does it support the newer ACCESS protocol.

Before flying with ACCST for the first time, the MPM's frequency must be calibrated using a FrSky receiver as a reference. The procedure is straightforward, and once the calibration setting is known it can be copied into subsequent binds.

The interface between OpenTX and the MPM is well designed - each can be updated independently, and OpenTx will always list the available protocols.

Overall I think the MPM is a cool system, and by all accounts pretty effective.

[edit 31 Mar 2020: the MPM now supports ACCST V2.1 (hooray!). It also adds another clever feature: a 'receive' mode, which allows it to clone the GUID of an existing transmitter, for seamless sharing.]

The case 

The case is a decent moulding with rubberised grips at the side and back. It's comfortable to hold, though I prefer the slightly chunkier feel of the X9D. Unlike the ergonomically challenged X10, I have no difficulty pushing the sticks into the top inner corner.

The carry handle incorporates a moulded grip - a nice touch. However the handle projects back quite a long way, so extra space may be needed in the backpack. A compact folding handle is available as an extra.

Top view, showing substantial carry handle

Sticks and switches

The gimbals are Hall effect units. Stick length and tension are adjustable. The sticks are nice and smooth, and there's none of the 'creaky spring' sound which I get on my X9D Plus.

However the stick feel slightly odd, the tension being higher in one direction, and weaker - and non-linear - in the other. The result is that pushing the right stick towards the top left corner is like balancing on a pin - the gimbal wants to return to one or other axis. It only happens in that quadrant.

The layout of the switches is similar to the FrSky X10, except that the 6-position switch is replaced by six illuminated buttons. From a programming perspective they work the same. Like the X10, a couple of extra trimmers are provided (T5 and T6) - great for mix adjusters or auxiliary functions.

The transmitter can accommodate two extra switches or pots (SI, SJ), if you're prepared to do a bit of drilling and soldering. A typical use would be to install momentary buttons, for tasks such as querying RSSI or pack voltage.

Top view showing mini-USB and trainer ports

One area which could be improved is the side levers - it's difficult to achieve fine control as their travel is very short, and there's little friction. The centre detent is also rather weak.

The sound from the speaker is clear, and volume is good.

User interface (OpenTx)

Like the FrSky X10 and X12S, the T16 Pro has a 4.3 inch 480x272 colour TFT display. It also uses the same widget based variant of OpenTX - and suffers from the same deficiencies. In particular, the default view is almost bare; it shows just the model name, plus some icons for RSSI and battery level.

Default screen is a bit bare.

To show more info, you have to add widgets, and this can rapidly get tiresome if you have several models due to the less than intuitive navigation system. Also widgets can not be configured inside Companion.

To try and improve matters, I’ve written a widget which displays basic info in a single large pane. You can download the widget from here.

My 'show it all' widget

As you can tell, I'm not a great fan of the widget-based variant of OpenTX. The X9D's interface may not be as pretty, but all the basic info is just a couple of clicks away. Furthermore, the X9D's telemetry scripts (the equivalent of widgets) can be configured in Companion.

External module bay

The external JR-style module bay adds considerable flexibility. In particular, it permits the use of protocols which are not supported by the MPM, such as Crossfire and M-LINK. Also, by swapping a module between different transmitters, you can swap tx’s without needing to rebind. Or you might just be happier using an 'official' module (remember that the MPM depends on reverse engineering the official protocols.)

Curiously, Jumper skimped on the module bay dimensions - my XJT just module only just fits (after pressing hard), and my M-LINK module refuses to click in place at all. An extra millimeter in depth would have made all the difference.

External module bay with FrSky XJT module

To cover the hole, my unit was provided with an empty module case. It looked untidy and rattled, so I made a simple plate for it (downloadable from Thingiverse). I rather like the colour accent from the pink PLA!

Printed module bay cover

The insides

Access to the electronics is easy - just pull off the rubber panels and undo six screws. The internals look neat and tidy.

The switches are soldered to small daughter boards, so there’s no chance of them working loose or being misaligned. On the downside, it  means that swapping out an individual switch is not a simple task. So if you like the momentary switch on the left hand side (for DLG), this transmitter may not be for you.

Ribbon cables woes

Almost all the interconnections use ribbon cables. On the plus side, it avoids clutter. However there have been a disturbing number of reports of failures causing buttons to behave unexpectedly or not work at all. Moreover the sockets reportedly lose their effectiveness after a few insertions.

I checked out a couple of the cables on my tx (those with more of the blue leader visible), and while the contacts seem fine, one of the ribbons had not been fully inserted into its socket.

Neat innards. Note use of ribbon cables.

Battery and charging

Power is supplied via two 18650 LiIon batteries (not supplied); these fit into a tray which connects to the tx via a short balance lead.

Takes 2 x LiIon 18650 batteries, requires external charger.

To charge the battery, it's necessary to use an external charger which means removing the tray and yanking out the cable - not helped by the battery hatch being rather stiff. In short, the T16 is crying out for USB charging; in the meantime various aftermarket solutions are available.

In summary

The T16 Pro is a radio of contrasts. On the one hand, it's nicely designed, feels comfortable in the hand and has adequate build quality. The multi-protocol module adds great flexibility and by all accounts works well.

Nothing's perfect though, and there are some significant negatives. These include: lack of internal battery charging, feeble sliders, asymmetrical stick action and - most critically - those issues with the ribbon cables. In short, the T16 Pro could so easily have been a great budget radio, but it just feels a little, well, unfinished.

As to whether the T16 Pro is going to replace my X9D Plus.. well you've probably guessed, it's the the older radio which still hits the sweet spot. It's got nicer sticks, a slicker interface, and is easier to live with. And it uses proper connectors.

In the meantime, watch out for the forthcoming Radiomaster TX16S. It sounds like a more developed knock off of the T16 Pro, and should address at least some of the issues identified in this review.

[Update 23 June 2020] Jumper have been pretty responsive with regard to the ribbon cable issue and have started distributing replacement packs to their agents. I've just received a set. I've also ordered a USB-C upgrade board (to permit internal USB charging), as well as the folding handle upgrade. So while this is not going to be my #1 radio, it'll get a good stab at being #2.