Small range with OpenThread.

[Kostiantyn Makhno]

Hi there, I tested range on NRF52840 with Thread SDK, so I have got small enough range. The test has been performed indoor, power transmission 0dBm, the range result is 10m. When I changed power transmission to 8dBm the result is approximately 13m. What I do wrong? Does someone have any idea? 

P.S.: How I can change IEEE802.15.4 i.e. to LR-BLE or BLE-1Mbit, is it possible?

[awneil]

You need to give more details of what, exactly you used and how exactly, you performed your tests.

In particular:

• Was this with two nRF52840 boards ?
• Did you increase the Tx power at both ends of the link?

Kostiantyn Makhno said:

How I can change IEEE802.15.4 i.e. to LR-BLE or BLE-1Mbit, is it possible

They are entirely different radio links - so you would have to redesign & re-implement your entire system.

Yes, the nRF52840 can do both IEEE 802.15.4 and BLE.

[Kostiantyn Makhno]

It is particle xenon board with nrf52840 chip with PCB antenna. Yes, I changed power at both ends. So, what I observed that is most significant influence has the direction of the antenna, and so example on distance 0.1m I got RSSI -28dBm, then I moved one of the boards on 0.5m and got RSSI -50dBm, it seems to me that is strange behaviour. So, Is there a difference multicast or unicast I use?

[Kostiantyn Makhno]

Influence on the range.
<So, Is there a difference multicast or unicast I use?

[awneil]

Kostiantyn Makhno said:

most significant influence has the direction of the antenna

PCB chip antennas are often quite directional

The antenna datasheet will show the radiation pattern - ie, how the gain varies in different directions.

It might be included in the Particle documentation - otherwise you will have to google the particular chip antenna used ...

Kostiantyn Makhno said:

it seems to me that is strange behaviour

No - it is perfectly normal & to be expected.

Kostiantyn Makhno said:

So, Is there a difference multicast or unicast I use

What do you mean by that?

[Kostiantyn Makhno]

I mean, that when I use multicast transmission I get better range than I use unicast. But I think it doesn't matter. 

[Kostiantyn Makhno]

So, last measurements I had a range approximately  30 meters with 0dBm. By 8dBm I had ~32 meters. Although, perfectly I should get the range by sqrt(Transmitter Power) times more than by 0dBm.