I am really confused about ETSI standards for SRD. I need some ETSI standard which regulates frequency band 433 MHz (433,050 MHz to 434,790 MHz).

  1. I found ETSI EN 300 220-1 V3.1.1 (2017-02) - it seems like the latest, but there I can not find any information about maximal TX power and bandwidth on specific frequencies.
  2. I found ETSI EN 300 220-1 V2.4.1 (2012-05) where is chapter 7.2.3 for limits. There is clear table with frequency - power limit and bandwidth.

Which ETSI is valid? The newer without limits, or the older one?

  • \$\begingroup\$ Check out part 2 of the standard, ETSI EN 300 220-2. \$\endgroup\$
    – Klas-Kenny
    Commented Jun 3, 2022 at 11:22

1 Answer 1


Output power and bandwidth aren't regulated through a standard but through EU and national directives.

Different nations have different requirements of this licence-free band. EU has attempted to standardize it somewhat with 2006/771/EC, with amendment 2013/752/EU. In the latter you can see various available alternatives 44a, 44b, 45a, 45b, 45c.

Simplified, it means:

  • You can either stay within 433,05-434,04 MHz with 10mW ERP, 10% duty cycle and no bandwidth requirement.
  • Or you can stay in 434,04-434,79 MHz with 10mW ERP continous transmission but 25kHz channel spacing (narrowband transmitter).
  • Or you can go with the 1mW ERP, optionally with broadband modulation > 250kHz and then send across both 433,05-434,04 MHz and 434,04-434,79 MHz.

Also check out the 868 MHz bands. There's no coincidence that these are license-free too, because that's where your 1st harmonic is at.

Many EU and European nations follow the above to the letter. A few nations like Germany and Sweden allow more liberal use of the band still. In case national directives are different than EU directives, the national requirements take precedence. To know for sure, check with the national radio authorities.

This is also assuming that your device is compliant with EN/ETSI 300 220-2. The v3.1.1 that you found is the correct one used for CE marking, it is harmonized below the Radio Equipement Directive ("RED") 2014/53/EU. From the EU RED directive web page you can find a list of all harmonized standards here. You'll find EN/ETSI 300 220-2 v3.1.1 in that list, which is how you know which version to use.

EN/ETSI 300 220-1 describes measurement and testing, EN/ETSI 300 220-2 contains the actual requirements.

So if you for example go for the 25kHz spacing, then 25kHz becomes your occupied bandwidth (OBW) as mentioned in 300 220-2. If you go with the 10% duty cycle version then you can state the bandwidth yourself, assuming it is less than 250kHz and that you stay within the band.


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