[HELP] Transmit power restriction for RT-N66U

[RMerlin]

So you are talking theoratictly and I am saying what happened when I raises the value 10 mW. Why inSSIDer showed the invrease of 4 dBm after the change in TX settings coould be either because the value was changed or just Asus own firmware doing the change. The environment was the same , the distance the same ...

Was it still on the same channel, and same channel width? Could also be the router that switched the tx/rx antennas through AiRadar between the the two tests.

 

[JingYou]

No, CFE update carries all settings from old CFE to new one.

1. A CFE just stores default NVRAM variables which applied only at "Reset to default" command.
2. A default values will be copied from CFE itself to NVRAM area. A firmware (include Wi-Fi driver) works only with this writeable copy.

So all you have to do is to change some NVRAM values to bypass a regional restrictions (which I strongly do not recommend to bypass):

It will work until you do "Reset to default" command.

Please keep in mind, to cover a wider range a SNR (singal/noise) parameters is more important then power itself. Higher power leads to higher signal distortions.

It doesn't work, after inputs and rebooting all via telnet... still gives the following:

Tx Power adjustment 200 mW
Set the capability for transmission power. The maximum value is 200mW and the real transmission power will be dynamically adjusted to meet regional regulations

 

[TonyH]

Hi,
In a peculiar case if the signal level was on the verge of knee threshold(re: quieting point), regardless of signal level signal auality will
be very much useable.

 

[mikeg]

Yes , the channel was the same and the channel width also. Who knows why it changed and why I can not tell. The only thing is that it is strange...

Was it still on the same channel, and same channel width? Could also be the router that switched the tx/rx antennas through AiRadar between the the two tests.

 

[sddt]

Did it really works? when i set this to 500 or 300, at next boot he set it back to 80 on both radio's? should i do something additional?

 

[HTMLSpinnr]

So you are talking theoratictly and I am saying what happened when I raises the value 10 mW. Why inSSIDer showed the invrease of 4 dBm after the change in TX settings coould be either because the value was changed or just Asus own firmware doing the change. The environment was the same , the distance the same ...

Other factors can influence perceived RSSI, including client and antenna position, obstructions, humidity, etc. Was the reading consistent, or did it bounce all over, and the 4dBm increase was the peak increase?

The folks here who have spoken out about reciprocal power are correct. There's little point in going to 500mW if your clients can't return that sort of power. Most mobile devices hang out closer to the 50mW or less range with antennas that aren't capable of more than 2-4dBi gain.

WiFi is a two-way communication. If your client can receive signal from a "really loud" AP, but can't transmit at a point where the AP can receive at similar RSSI, you're accomplishing very little except for creating a frustrating experience.

Now, if you're attempting to bridge two routers with an equal transmit level, you'd be far better off equipping the devices with a highly directional yagi style antenna and using a lower transmit power. The antenna gain will take care of the rest without distorting the signal, and you'll be equally capable of reciprocating the signal at the far end. Plus, you'll be far less likely to violate any regulations or piss off your neighbors.

That all said, I agree that specialized equipment to handle the distance (appropriate antennas and amplifiers) is a better approach if you're attempting a long-range bridge. Using multiple APs is a better approach if you're simply trying to provide better coverage in a larger building. In either case, a single ASUS router is likely not the right tool for the job.

Perhaps if you explain what your use case is, the folks here can provide a bit more guidance to help you achieve your goal.

 

[DrTeeth]

Higher power leads to higher signal distortions

This is not inevitable and depends on the design of the transmitter. The same applies to audio amplifiers and for the same reasons too.

 

[richto]

We could really do with an editor or setting that lets you modify the restrictions.

For instance the EU has no restrictions on maximum transmitter power, yet the firmware limits it. If I set the system to the US to get round it, I get fewer 2.4GHz channels to use...

 

[DrTeeth]

We could really do with an editor or setting that lets you modify the restrictions.

For instance the EU has no restrictions on maximum transmitter power, yet the firmware limits it. If I set the system to the US to get round it, I get fewer 2.4GHz channels to use...

The EU itself may not have any limits, but ALL countries within the EU do.

 

[richto]

The EU itself may not have any limits, but ALL countries within the EU do.

As far as I am aware, there are no limits on WLAN transmitter power as per the ETSI regulations for anywhere in the EU. The only restrictions are on EIRP.

 

[DrTeeth]

As far as I am aware, there are no limits on WLAN transmitter power as per the ETSI regulations for anywhere in the EU. The only restrictions are on EIRP.

Every use, licensed or officially unlicensed has a power limit...EIRP is just a way of defining power output relative to a certain type of (theoretical) antenna, an isotropic one. Power and frequency allocations are set by national administrations and not any other body. I have been a radio ham for nearly 40 years and that is how it works with radio spectrum regulation.

 

[Stimpy]

I never have understood the way WiFi power output is enforced.

Why the hell can't we tell the router what country we live in, then set the power to the limit for the given country?

EU law states that a wireless device must not output more than the limit of the country the device is SOLD in. So as long as the manufacturer sets a responsible DEFAULT power output, then it can be left to the end-user to make any changes. This is permissible by law, so why don't we have a solution to this already? It's really not rocket science.

I have never known anybody to be prosecuted for increasing the power limit on consumer hardware, as it is simply not high enough power output to cause any kind of interference to government or military equipment.

Please somebody make a GUI for actually making REAL changes to the WiFi power output level, that survive a reboot. I don't want to hear about signal distortion, or burning out radios, or the age old argument of "it does no good to only increase the power output of your router, you have to increase the power output of all devices", well, duh, that's what we are asking for, we have to start somewhere!

 

[DrTeeth]

It is not permissible under UK law to exceed the power limit laid down. In the regulations and never has been. I suspect it is the same elsewhere as all jurisdictions have limits.

 

[Stimpy]

It is not permissible under UK law to exceed the power limit laid down. In the regulations and never has been. I suspect it is the same elsewhere as all jurisdictions have limits.

But the limit in the UK is 500mW. This router won't go over 100mW.

And exactly who will be knocking down my door if I up the power to 501mW? (if it was possible)

 

[DrTeeth]

And exactly who will be knocking down my door if I up the power to 501mW? (if it was possible)

If I told you, I'd have to kill you; then 'they' would have to kill me .

It is not just government and the military that are protected by power limits. I'm sure you'd be the first to complain if you wi-fi was rendered useless by some selfish moron transmitting way in excess of the legal limit. A limit to which receivers are designed to work regarding break-in and signal selectivity by the way.

 

[richto]

It is not permissible under UK law to exceed the power limit laid down. In the regulations and never has been. I suspect it is the same elsewhere as all jurisdictions have limits.

There is no WLAN transmitter power limit in the UK, or as far as I can find, anywhere in the EU. Only an EIRP limit.

From OFCOM:

Frequency band: 2400 MHz to 2483.5 MHz
Application: Wideband Data including RLAN
Maximum transmit power limit:
a) -10 dBW (100 mW) EIRP
b) PSD for frequency hopping -10 dBW (100mW) EIRP per 100kHz
c) PSD for other forms of modulation -20 dBW (10mW) EIRP per 1 MHz

 

[richto]

Every use, licensed or officially unlicensed has a power limit...EIRP is just a way of defining power output relative to a certain type of (theoretical) antenna, an isotropic one. Power and frequency allocations are set by national administrations and not any other body. I have been a radio ham for nearly 40 years and that is how it works with radio spectrum regulation.

As stated there is no transmitter power limit. EIRP is a measure of the output from the actual antenna.

It is of course up to you to make sure that you use an appropriate antenna and / or balun with a high power transmitter to ensure that the EIRP limits are not exceeded.

The key point is that you can make a transmitter with any power output you like and it will be legal to use anywhere in the EU with the appropriate antenna. i.e. you can't break the law in the EU just by making a firmware or transmitter that provides a certain power level...hence the ability to adjust it for EU users would be a good and legal thing to have....

 

[DrTeeth]

As stated there is no transmitter power limit. EIRP is a measure of the output of device + actual antenna.

I believe you are mistaken. EIRP is the output based on a throetical isotropic antenna; http://en.wikipedia.org/wiki/Equivalent_isotropically_radiated_power. It also makes it illegal to use a directional antenna to exceed that limit, so one has to reduce the power if squiring it in one direction http://en.wikipedia.org/wiki/Effective_radiated_power.

In short, if one is limited to 100mW EIRP, that does not mean one can squirt the whole 100mW in one direction with a directional antenna.

From OFCOM:

Frequency band: 2400 MHz to 2483.5 MHz
Application: Wideband Data including RLAN
Maximum transmit power limit:
a) -10 dBW (100 mW) EIRP

 

[RMerlin]

Regardless of the law-related debate, I will make one thing clear tho: I have NO intention of implementing any webui interface that would allow one to change his regulation country in the router, or bypass the limitations implemented and enforced inside the driver.

 

[richto]

I believe you are mistaken. EIRP is the output based on a throetical isotropic antenna; http://en.wikipedia.org/wiki/Equivalent_isotropically_radiated_power. It also makes it illegal to use a directional antenna to exceed that limit, so one has to reduce the power if squiring it in one direction http://en.wikipedia.org/wiki/Effective_radiated_power.

In short, if one is limited to 100mW EIRP, that does not mean one can squirt the whole 100mW in one direction with a directional antenna.

No, i'm not mistaken - as stated there is no limit on transmitter power.

As per your link "EIRP can take into account the losses in transmission line and connectors" and also SWR loss, etc. so it is possible to run more than 100mW transmitter power, and remain fully legal.