[OpenWrt-Devel] Fix TX power handling

[Matthias Schiffer]

This is just the factor of 1/2/3/4 (approximated) in dB:

10^0.0 = 1
10^0.3 ≈ 2
10^0.5 ≈ 3
10^0.6 ≈ 4

I've seen these numbers being used in WLAN drivers to account for the
antenna array gain, so at least this part of the TX power computation might
already be working as expected.

Kind Regards,
Matthias


On 4/30/19 12:39 AM, Vincent Wiemann wrote:
> Hi Matthias,
> 
> thank you for the hint. That's funny, because someone from the German Federal Network Agency
> said that when radios have multiple antennas, the aggregated EIRP of the antenna array must not exceed the
> EIRP limits of a single antenna, but I've assumed this is done in hardware and not in software.
> 
> Can you hint me to the source for this lookup table?
> 
> Regards,
> 
> Vincent Wiemann
> 
> 
> On 29.04.2019 08:50, Matthias May wrote:
>> On 25/04/2019 17:54, Vincent Wiemann wrote:
>>> First EIRP is by definition ERP + antenna gain - cable loss.
>>
>> Hi
>> Small detail: Don't forget the antenna array gain.
>>
>> So EIRP as:
>> Antenna Port Power
>> + Antenna Gain
>> + Antenna Array Gain
>> - Cable Loss
>>
>> The Array Gain as a simple lookup table:
>> 1 Antenna: 0
>> 2 Antennas: 3
>> 3 Antennas: 5
>> 4 Antennas: 6
>>
>> BR
>> Matthias
>>
> 
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> 


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