Re: wireless-regdb: Wrong ETSI tranmit power without TPC

Johannes Berg
2025-05-16T09:29:48Z

On Fri, 2025-05-16 at 11:22 +0200, Alexander Wilhelm wrote:
>
> I referred to the following EU Rules:
>
> * ETSI EN 300 328 V2.2.2 (2.4 GHz)
> * ETSI EN 301 893 V2.1.1 (5 GHz)
> * ETSI EN 300 440 V2.2.1 (5.8 GHz)

Is that really all that relevant? I don't think ETSI has normative
power, that's left to the per-country regulators, IIRC. Who in Germany,
as demonstrated, did a mix of units for the range you were talking about
before.

> The problem with them is that almost always the unit _mW_ is used. And the
> reduction without TPC then is given in _dBm_. However, for 5.8 GHz (SRD devices)
> the transmission power is stated as 25 mW. Does the EU Rules means 14 dBm or
> only 13 dBm are allowed?

It means just that, 25 mW is allowed? I'm not sure you should read more
into it than written.

You could argue that 14 dBm is "close enough" at 25.11886 mW (0.47% too
much), but perhaps that's not something the computer should do, but
rather whoever updated the database. It might even differ slightly per
country, I guess, technically - though here the German document [1]
states the same.

[1] https://www.bundesnetzagentur.de/SharedDocs/Downloads/DE/Sachgebiete/Telekommunikation/Unternehmen_Institutionen/Frequenzen/Allgemeinzuteilungen/FunkanlagenGeringerReichweite/2018_05_SRD_pdf.pdf?__blob=publicationFile&v=2

So perhaps the database could state 14 dBm with an appropriate
justification, but the conversion from 25 mW to eventually rounded down
13 dBm also seems right.

johannes