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I have ALFA AWUS036NH network adapter on raspberry pi model 2B running the latest raspbian. ALFA AWUS036NH should be capable of delivering up to 2W of power according to specs. Following some tutorials on the web and tweaking the CRDA database, I'm able to set TX power up to 33dbi (2W).

#iwconfig wlan0 txpower 33

I've installed USB power meter to measure the actual current consumption of the raspberry. Raspeberry with peripherals attached, but without the network card, uses about 400mA. When I plug in the network adapter, current usage increases to 600mA, which is comparable to most other network cards.

My understanding, that at least 400mA at 5V is required to transmit 2W. However, there are no changes in current usage when I change the TX power via iwconfig. The network adapter is connected to a network, so it is transmitting something. iwconfig output confirms the new TX setting.

Why the usb power does not change when I change TX power via iwconfig? Could it be that there is an internal "limiter" inside the network adapter?

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I wanted to make only a comment about what my theory is about your question is, but I need 50 points to comment and I don't have that.

Here is my theory. Plain and simple they are lying about its power output, they can wright whatever they want on the box.

If you live in the USA or Canada it is limited to 100 mw max if your in the USA you could search the FCC web site for the true output power but from what I have read on some forums the output could be anywhere from 43 to 400 mw.

And even if it could put out 2000 mw a lot of computers could not supply enough current to run it and it would shut the card down unless the drivers forced it to run at a lower output

EDIT: try setting it to 9000dbi see what happens

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  • You're right about FCC regulations, but that's is why you need to re-compile regulatory database or switch device location to e.g. BO ( Bolivia ), that allows 30dbi. However, my device is locked to GB, so I've modified setting for UK. My assumption is that the tx limits are also "embedded" into the device itself. Jun 23, 2015 at 10:42
  • BTW, you cannot set it higher then the limit in CRDA db.txt file, so 9000dbi won't work. Jun 23, 2015 at 10:45

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