"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?

[ovrebekk]

Hi

Was the output power of the nRF52832 +4dBm when you compared it, or was it lower?

I strongly doubt the antenna of the Tile module is better than the one on the DK, due to it's smaller size. If they did a good job tuning it (which I assume they did, judging by the range) it should be comparable.

If the range is double this is most likely caused by higher output power, and double the range equals roughly 6dB higher output power.

To summarize, if the Tile was double the range of the nRF52DK at +4dBm, then I doubt the nRF52840 at +8dBm will be able to beat it, but it should get you close.

As a final note, the TC35678 appears to be a Toshiba part. I wasn't aware they were in the BLE space, but these days everyone is.

Best regards
Torbjørn Øvrebekk

[jumpingfool]

Hi Torbjorn - really appreciate your help.

I managed to get hold of a PCA10056 today and do some experimenting. I built the proximity demo with the TX power set to 8db, flashed the board and then did some comparisons against the Tile board.

With the antennas on both boards optimally positioned it is a very close race, with the Tile giving roughly another 10-15 feet of additional range over the PCA10056. My guess is the RF amp on the Tile board is probably boosting the signal to 10db which is giving it a slight edge. Impressive they've managed to get the power budget down so low if that's the case though - any idea what manufacturer the "X8 OZ4D" part comes from?

However, it is a different story when the boards are rotated and positioned such that the antenna is at 90 degrees to the receiver. Here the PCA10056 drops out at about half the distance of the previous test while the Tile board shows almost no impact.

Given the application of the Tile board as a key finder where orientation to the receiver is an unknown clearly the funky looking antenna is optimised for this use case. Do Nordic offer a keyfinder reference design with a similarly optimised antenna, or if not could we engage you to assist with optimising our design?

[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.

[ProfHindsight]

jumpingfool said:

any idea what manufacturer the "X8 OZ4D" part comes from?

RFFM6205 - Qorvo part