What are the best settings for MY_RF24_PA_LEVEL?



  • I spent some time googeling the best value's for MY_RF24_PA_LEVEL, but i could not find a definitive answer. I hope my questions are not very stupid, but i would like to understand the type of radio and its settings better.

    First i would like to know which NRF24L01 are the best. From what i have read, the NRF24L01 + PA + LNA has a build in amplifier and is therefore more powerful. Usually these have a external antenna mounted by a SMA connector. The normal NRF24L01+ have a PCB antenna.

    For a gateway i would guess the NRF24L01 + PA + LNA would always be the best choice right? Same for a repeating node i would guess... Off course this is amusing power consumption, costs of the more expensive NRF24L01 + PA + LNA radio, and the lager size are no problem. Or am i missing something here?

    Considering range. The best combination is always NRF24L01 + PA + LNA for both nodes if i understand right. For some node's i prefer the smaller, cheaper, and less power hungry NRF24L01+. Does using a NRF24L01+PA+LNA as a gateway to communicate with the NRF24L01+ offer any improved performance over using a NRF24L01+ for both the gateways and the node?

    Will MY_RF24_PA_LEVEL work on both the NRF24L01+ and NRF24L01+PA+LNA, or will it only work on the NRF24L01+PA+LNA?

    From reading the library API i understand the default value is RF24_PA_MAX. I'm a bit of a noob with Arduino, so i'm not sure how this works. If i make a sketch without manually adding MY_RF24_PA_LEVEL, will the library set it to RF24_PA_MAX automatically?

    So what is the generally the best value for the MY_RF24_PA_LEVEL when used with a NRF24L01+PA+LNA on a gateway? A lower power will obviously mean less range. But i can imagine a very high power can sometime also cause problems. So is there a sweet sport for a average configuration when the gateway is inside of a regular house where all sensors are in a max 20m range (with walls) and the furthest sensor is maybe 30-40m away?



  • Anyone? Or am i asking stupid questions again? :confused:



  • Hi SuperKris,

    most likely, there is not a definite answer to your questions.

    First a very good point for a lot of info around the nrf's: https://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo

    I personally got best results using the PA+LNA-Versions and additional base modules, power sourced through 5V with PA-Level set to max.

    This is the standard-level which is used as long as there is no explicitely defined other level. This is the standard mechanism using the myconfig.h settings. Keep eyes open, as this is defined to LOW e.g. in the GW-Sketch...

    MAX will also work with the non PA+LNA-Boards, but keep in mind using this setting also means higher power consumption, so soucing the NRF through Arduino's 3.3V-PIN might not work.


  • Hardware Contributor

    @SuperKris said in What are the best settings for MY_RF24_PA_LEVEL?:

    Does using a NRF24L01+PA+LNA as a gateway to communicate with the NRF24L01+ offer any improved performance over using a NRF24L01+ for both the gateways and the node?

    I am also really interested in the answer to this question as I am planning to switch from a serial to a MQTT gateway and could change the radion in the process. Can't use the PA/LNA version on my battery powered nodes though, only on the gateway. Does that even help?



  • @LastSamurai
    According to my personal experience I would answer with a clear yes! The +PA+LNA-Version gets better receiving results and generates a stronger signal when sending. So -apart form adding a capacitor- changing the module on the GW imo is also an action to recommend to improve the overall results. You may in addition think about shielding both decoder chips (not the antennas).



  • @rejoe2 said in What are the best settings for MY_RF24_PA_LEVEL?:

    Hi SuperKris,

    most likely, there is not a definite answer to your questions.

    First a very good point for a lot of info around the nrf's: https://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo

    Thanks for the link, there was some useful information there

    I personally got best results using the PA+LNA-Versions and additional base modules, power sourced through 5V with PA-Level set to max.

    This is the standard-level which is used as long as there is no explicitely defined other level. This is the standard mechanism using the myconfig.h settings. Keep eyes open, as this is defined to LOW e.g. in the GW-Sketch...

    One of the reasons i started asking about this that it was defined to LOW in the default gateway sketch. I started to google on these settings and found a couple of topics where they advise to lower MY_RF24_PA_LEVEL. This made me even more unsure about selecting the right voltage level.

    MAX will also work with the non PA+LNA-Boards, but keep in mind using this setting also means higher power consumption, so soucing the NRF through Arduino's 3.3V-PIN might not work.

    I always use a e-cap on every PSU. For this the radio i often use 47u, and a 470-1000u on the arduino 5V. Also always a 50n in parallel as close to the chip as possible. I dont use a extra regulator board, but i use arduino's with a strong 3V3 PSU. I love the one's by Robotdyn. They have a AMS117 (SOT223 size i think?). They specify the 3V3 at 350mA. I have not tested this, but the AMS117 should be good for 1A if it can cool enough, so i expect it to be able to deliver plenty of power.

    @rejoe2 said in What are the best settings for MY_RF24_PA_LEVEL?:

    @LastSamurai
    According to my personal experience I would answer with a clear yes! The +PA+LNA-Version gets better receiving results and generates a stronger signal when sending. So -apart form adding a capacitor- changing the module on the GW imo is also an action to recommend to improve the overall results. You may in addition think about shielding both decoder chips (not the antennas).

    Does shielding actually improve results? This is interesting to me. how should one proceed with this? First warping it in plastic, and next in aluminium foil? Should the shield be connected to the ground pin, or maybe even to the shell of the USB?



  • @SuperKris said in What are the best settings for MY_RF24_PA_LEVEL?:

    I always use a e-cap on every PSU. For this the radio i often use 47u, and a 470-1000u on the arduino 5V. Also always a 50n in parallel as close to the chip as possible. I dont use a extra regulator board, but i use arduino's with a strong 3V3 PSU. I love the one's by Robotdyn. They have a AMS117 (SOT223 size i think?). They specify the 3V3 at 350mA. I have not tested this, but the AMS117 should be good for 1A if it can cool enough, so i expect it to be able to deliver plenty of power.

    To be honest, I never made any measurements wrt. the power supplied by the 3.3V-Pin, because I found it much easier to use these boards. Basically, the ones I used consist of an AMS and some caps. So results may not differ much between a self-engineered version and these modules. For quite a long time I used one GW that uses an AMS directly for power supply. That also worked pretty good.

    Does shielding actually improve results? This is interesting to me. how should one proceed with this? First warping it in plastic, and next in aluminium foil? Should the shield be connected to the ground pin, or maybe even to the shell of the USB?

    Once again, I didn't investigate much in analysing this in depth, just found it somewhere around in the depth of the web:simple_smile: . I made a couple of shieldings (plastic tape, some thin alu foil, and again plastic tape for fixation, no connection to ground) and at least, results didn't get worse...
    At around the same time the pa+lna-modules and the adopter boards arrived, so my transmission problem was solved anyhow.
    Most likely, it would be a good idea to connect the shielding to ground, but I am not an real expert...



  • I have a node that is not working perfectly. I'm not sure about the reception problem, but it doesnt help its in a thick aluminium housing. I'll try some foil on the radio of the gateway!


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