nrf24L01+ , problems while transmitting from ground

[AlexandruG]

Hello,

We are trying to put togheter a custom mesh communication protocol based on nrf24L01+. Everything was good until we made transmission tests outside, from ground level. While at 0db, 250KHz the signal is OK, we encountered range transmission problems when putting the sensors on the ground; the range fell to about 4-5 meters; things got worse when between the sensors there was a parked car.

We are using the boards from sparkfun.

Your help would be very appreciated on how to solve this issue, as we want to design the pcb with all the components. The sensors will be mounted on the ground so you can imagine that this a great deal for us. As, probably, you can imagine that we are not very good on radio transmission.

We are kind of stuck with the NRF24L01+, so please don't tell me there are no options :)

Desired range for us is 10-12 meters.

Thank you in advance, Alex

[ovrebekk]

Hi Alex

4-5m sounds very low, especially in 250kbps mode.

Do you have a picture of the module during your test?

I assume the module you use is this one?
It appears they don't have any tuning components on the antenna, which means the antenna is probably not very well tuned (a perfect 50 Ohm antenna doesn't really exist). It is very likely that a different type of module would yield better results.

One thing you can try to is to remove the antenna completely, and solder on a ~23mm wire instead. If this improves performance you can be pretty sure that the antenna is to blame.

Best regards
Torbjørn