Maximize range on nRF52840 pdk

RE: Maximize range on nRF52840 pdk

run_ar — Tue, 28 Mar 2017 08:56:10 GMT

Linking to new question here.

RE: Maximize range on nRF52840 pdk

endnode — Sun, 26 Mar 2017 17:40:49 GMT

What do you mean by "default" Tx Power value? There is only default value of that register and then default value decided by app which is HW&FW specific (use case + certification constrains + HW limits). Hard to say why Nordic decided to remove that function call from the example but it probably doesn't matter. For some reason they don't want +4dBm but 0dBm, you can change it easily and recompile (btw. nRF52840 should support up to +9dBm).

RE: Maximize range on nRF52840 pdk

Matija Tudan — Sun, 26 Mar 2017 16:55:43 GMT

Yes, but not just after the reset. Generally what is the default tx power value? In the 13.0.0-1.alpha SDK version it is by default set to 4dBm from the tx_power_set() function.

RE: Maximize range on nRF52840 pdk

endnode — Sun, 26 Mar 2017 13:42:47 GMT

Oh you mean what is the default value of TXPOWER register after reset? That seems to be zero.

RE: Maximize range on nRF52840 pdk

Matija Tudan — Sun, 26 Mar 2017 13:06:27 GMT

Just like Ole mentioned, in the 13.0.0-1.alpha SDK version, in the ble_app_att_mtu_throughput example in the main file there is the tx_power_set() function which sets the tx power value. In the 13.0.0 SDK version (2017 version) in the same example in the main file there is no tx_power_set() function or anything similar. You can manually add the function to set the tx power value, but I want to know what is the default tx power value and how it is being set by default.

RE: Maximize range on nRF52840 pdk

endnode — Sun, 26 Mar 2017 12:44:50 GMT

Can you refer to specific line of specific file and SDK version? Of course Soft Device has API call to set Tx Power so it's probably just some refactoring in the examples...

RE: Maximize range on nRF52840 pdk

Matija Tudan — Sun, 26 Mar 2017 09:25:44 GMT

Where did the tx_power_set() function disappear in 13.0.0 SDK?

RE: Maximize range on nRF52840 pdk

embo san — Thu, 23 Feb 2017 11:59:58 GMT

just tested the PHY CODED and power_set(8), outdoors in a crowded street, with trams and cars, and we managed to reach 255m!

RE: Maximize range on nRF52840 pdk

Scott — Wed, 18 Jan 2017 02:24:54 GMT

Good to know, thanks!

RE: Maximize range on nRF52840 pdk

daguro — Sun, 15 Jan 2017 14:45:53 GMT

I paced off 110 meters and had no problems. I didn't repeat the test at 4 dbm. I'm pretty sure that I would have had no problems.

RE: Maximize range on nRF52840 pdk

Scott — Sun, 15 Jan 2017 13:39:52 GMT

What range did you end up getting after changing these? And was this in open air, line-of-sight?

RE: Maximize range on nRF52840 pdk

daguro — Wed, 11 Jan 2017 19:11:52 GMT

That worked.

Thanks for your help.

RE: Maximize range on nRF52840 pdk

Ole Bauck — Wed, 11 Jan 2017 11:26:00 GMT

Hi,

You can change the PHY to CODED. This will set the on-air bitrate to 125kbps which is a new feature of nRF52840 called long range Bluetooth, and will give you about 7dBm more sensitivity compared to 1Mbps, see here. You can do this if you use the example from SDK 13.0.0-1.alpha and SoftDevice S140 5.0.0-1.alpha (SoftDevice for nRF52840). There is an option called "Select preferred PHY".

You can set the tx power higher. The default in the example is 4dBm (supported by both nRF52832 and nRF52840). nRF52840 has an internal PA capable of tx power up to 8dBm. This is not an option to set while you are running the example, so you have to go into the code and change this. Look for the tx_power_set() function and change it to:

void tx_power_set(void)
{
    uint32_t err_code;
    err_code = sd_ble_gap_tx_power_set(8);
    APP_ERROR_CHECK(err_code);
}

You should also set the connection interval to the minimum (7.5ms). This will lower the time between each resent packet if you start loosing packets.

The features of nRF52840 is summarized here.