"Tile Pro" Tracker - Impressive Range

[jumpingfool]

I have recently purchased the newly released "Tile Pro" bluetooth tracker after noticing a number of reviews online were giving good reports in terms of the BLE range.

The device is using the TC35678 from TI connected to an RF amplifier that I've been unable to identify marked X8 OZ4D. It also has a pretty funky looking PCB antenna - you can see it in the FCC report here:

fccid.io/.../Internal-Photos-3495407

They claim battery life of 1 year on a CR2032.

Under test the line of sight range from this device is nearly double that I can achieve from the NRF52 DK. Is this a function of the amplifier, the antenna design or potentially both?

If I move my design to the 52840 with +8db output can I reasonably expect to achieve similar performance in terms of range and battery life, or will an RF amplifier need to be incorporated into the design in order to achieve this?

[endnode]

Also everything matters including PCB shape (= this might be more important for DK then "best" tuning), casing etc. (so if you think this thru there is no real "line of sight" test unless you send the thing into space and measure from the distance, there are always some holders or other objects which are close to the beacon and can absorb or reflect 2.4GHz waves... Still you can get close to that scenario and I do believe that Ruuvi tag has very good antenna design which can be superior to nRF5x DK boards.

[ovrebekk]

Hi

It's not unreasonable that the smaller Tile antenna would be more omni-directional. A straight monopole antenna will have a hole in the direction it is pointing, while a meandering antenna will have a more unpredictable (and usually more omni-directional) radiation pattern because of the many bends in the antenna.

I have never heard about the X8 part. Googling this part number didn't yield much either, so it's hard to say what it could be. Skyworks is the most common provider of PA solution in Nordic designs, but it doesn't look like one of those.

If you want to design your own PCB we are happy to look over your layout, and we can also assist in tuning the antenna if you don't have the lab equipment to do so yourself.

Best regards
Torbjørn

[jumpingfool]

Hi Torbjorn,

Thanks again for your help. After a bit more research I have found this module from notWired which pairs the nRF52832 with the SKY66112 and a chip antenna:

www.notwired.co/.../

I've ordered a couple to experiment with before we move to our own PCB design.

From reading the datasheet I can see that the PA must be toggled between TX and RX mode using GPIO in sync with the radio activity from the the Nordic SoC. Are there any examples/tutorials available that I could use to understand what modifications will be required to the SDK examples to enable them to drive the PA?

[endnode]

This is good description of PA/LNA built-in function in S132 and here is documentation of API call. There seems to be no usage of this structure in nRF5 SDK examples but there were people before you asking on this forum so using search with terms like "PA/LNA" should give you some rewards.

[jumpingfool]

Thanks to Torbjorn and endnode for their help with my question.

Just in case anyone else is looking to try out the skyworks power amplifier recommended by Torbjorn I can highly recommend this dev kit from notwired:

www.notwired.co/.../

Not only do they provide a reference design containing the NRF52832 and the Skyworks SKY66112-11 on a tiny board, they also provide example code showing how to interface the two using the Nordic SDK, which can then easily be translated to other applications. Using this I was up an running with my own application in just a couple of hours.

The radio module also has a handy set of 1.27mm headers (male and female) down each side that make it easy to incorporate the module into other designs - it's like a miniature PCA10040 dev board.

The range from the module with the PA set to high power is very impressive, adding around another 10 meters onto the (already impressive) range of Tile's TC35678 based design.

Fantastic!