Maximum allowed output power ESB

[TinyRick]

Hi Nordic folks,

We are developing a product using nRF52832 with a Power Amplifier (RFX2401C) for extended range. For communication we are using ESB with some modifications to allow the use of a PA. The PA will add +22dBm to the output power.

We plan to release the product in Europe and USA.

Do anyone have a summary of what we will have to do to comply with the regulations in these countries? I am sure that someone has had the same kind of problem before here.

I have read a bit of the regulations for devices operating in the 2.4GHz band in Europe (EN 300 328), but as most of these documents this can be hard to read sometimes. Therefore we would like to know if someone on this forum has some tips.

[bjorn-spockeli]

Hi Rick,

As far as I know, you're allowed to transmit up-to +30dBm in the US as long as the bandwidth at 6dB is larger than 500kHz.

In Europe there are several regulations when transmitting above 10dBm, described in ETSI EN 300 328 Chapter 4.3.2. The most "problematic" part is 4.3.2.3 Power Spectral Density, which is limited to to 10dBm per MHz. Thus, with a 2MHz bandwidth the maximum output power of 13dBm, transmitting above this limit will require you to hop between frequencies (minimum of 15 channels)

In addition there is a requirement to "Listen Before Talk" (chapter 4.3.2.6.2.2), i.e. you need to check whether the channel is used or not before transmitting as well as requirements of the Medium Utilization, i.e. duty cycle.

Best regards

Bjørn

[AmbystomaLabs]

You should clarify this would only be true for non-bluetooth applications. So, it needs to be proprietary protocol. There is no bluetooth spec allowing more than 20dBm. And, at 20dBm bluetooth there are requirements for monitoring requests for power reduction.

As you pointed out even with proprietary protocol the radio would likely fail PPSD (peak power spectral density) for most regulatory bodies. Further, ETSI have recently made their SAR requirements more restrictive and a high power device would have problems with SAR.

And we haven't even begun discussing the problems of band edge compliance with a 52832 with nearly 20dB of gain on it.

TinyRick should investigate this thoroughly before proceeding.