Radio experts can you anwer my noob question

Hardware Questions and Recommendations
1

So... I am using android device without RF shielding ( Material which was used for shielding got damaged during repair ( is safe to assume device has 0 shielding )

I'd like to reduce wifi power coming out of the device for some ease of mind... :smiling_face_with_tear: Don't laugh ik... it's low power but still

What idk is how RX TX work and how to use iw tool to check RX/TX of the device.... Could use some help w this

Anyways since I'm a noob I researched how and first stumbled upon iwconfig - which doesn't seem to work on my device ( all interfaces give : no wireless extensions when I type iwconfig into shell of device )

But iw works - and with it I can set the txpower in mBm to my desired level
iw wlan0 set txpower limit 700

After running this command I see lower signal on the openwrt realtime graph (from -40 dBm to -60 dBm) Android device reports wifi signal as excellent so I am asuming only openwrt is receiving lower signal which is expected.

wrt
wrt768×510 16.3 KB

.... Since I can set TX power of the device already - should I be concerned about RX power ?

What does RX power mean? Like do the antennas that receive signal use power for this ? ( I know routers have antenas for RX and TX , I am assuming phones have one each as well - so do those antennas emit any signal to the surroundings or just passively sit there and soak in ? )

Or is RX power simply some limit - like disconnect wifi when it falls below this limit?

iw doesn't have option to set RX power otherwise I would have played with it first before asking silly questions :upside_down_face:

1 Like
2

Not seeing a response from a more knowledgeable person, so I’ll take a stab here :wink:

I’m sure you can take RX power as a receive gain. This is local to the device and will most likely be DC. Purpose is for digitization only.

As you undoubtedly know, unshielded TX power will have an EMF (and hence SAR) impact… (although in these low power devices it may not have real world consequences).

3

Why aren't you using the OpenWrt config files to change settings?

Can you better explain?

No.

Maybe I should note that RF power is measured in Watts, just like Electrical power.

???

Can you show a screenshot of what you're talking about?

You set RX power for the device in question - on the other device (i.e. that's...Transmitting (Tx)). :wink:

4

This topic was automatically closed 10 days after the last reply. New replies are no longer allowed.