How much can you boost the output power of the Linksys WRT54G without messing it up?

[kehi]

I have been reading that you can boost the antenna output power on this model with various firmware updates. Can someone please provide a link where I can read more or if you know what the base setting is and what the range of the output power is. Does it matter if you use the factory antenna compared to a detached antenna? Thanks


BTW: I want to get two of these and use the firmware upgrade to bridge them to connect two wired networks.



UPDATE: Tried with stock antennas and it did not work. Read more in last post

 

[xanis]

There are some hacked firmwares for the WRT54G out there. There was one set from WiFi that let you boost signal strength but I can't seem to locate it. In the meantime, check out the firmwares from WiFi-Box. https://sourceforge.net/projects/wifi-box/

 

[JackMDS]

When you boost the Output power, it gets Hot. Therefore, the capacity of the unit to withstand the boosting depends on the environment. It seems that 60mW is safe (the original output is under 40mW); 80mW might be OK if to you are in a cool AC environment.

http://www.hyperwrt.org/

Whether a Boosted power unit is better then regular power with Directional Antenna depends on the Environment. As an example, if there is a metal Grid that blocks the signal it will block 60mW too.

One can try a Boosted unit with regular Antenna and then add a Directional Antenna if necessary.

There is No one set sure be inexpensive solution to extending Wireless. You have to try, taking into consideration that at the end you might spend more then you thought or an end up with some ?spare? hardware.

:sun:

 

[kehi]

thanks for the responses. Does the hyperwrt firmware or the wifi box firmware allow this router to be configured as a bridge? Thanks

 

[JackMDS]

Nope, the firmware in my link allows boosting and few other things No change in Modes.

The one that changes Modes is the sv*** something.

Many people here are using it, I do not like it (a personal matter).

This thread might give you a better answer: http://forums.anandtech.com/messageview...atid=36&threadid=1513386&enterthread=y

The biggest thread ever on the Network Forum.

:sun:

 

[cmetz]

kehi, this is the sort of material that separates the EEs from the boys. At the receiver end, raw power matters only as much as it takes for you to get a signal that your receiver is sensitive enough to see - in practice, power alone is not usually at issue. What matters more is the signal to noise ratio - SNR. That is, you need the signal carrying the data to be a certain amount stronger than the noise the receiver also sees along with it, in order for the receiver to pick the signal out from the noise. That noise comes from several places - including the transmitter itself. No transmitter is perfect, especially on its analog side, it introduces some noise along with the signal it's transmitting.

According to a lot of other research, when you crank up the power in the WRT's transmitter a little bit, you get more signal, and not much more noise - you win. But if you keep turning up the power in the WRT's transmitter, you start getting more and more noise, and you can quickly get to a point where you are transmitting more signal but also so much more noise that the signal to noise ratio is lower than if you left things alone.

So boosting the good signal of the WRT is not nearly as simple as just turning up the power - it's a matter of optimizing the SNR. And that is tricky. According to what I've read, the Linksys default settings are fairly close to optimal for most units.

Now, there's also another issue for you to consider - the device is only legally (per the FCC) allowed to transmit a certain amount of signal strength. So you need to be sure that if you go tweaking the output power to turn it up, that you are still within the legal requirements. It's not like you set the variable to 100% and the Gestapo comes knocking on your door - more like you go from being a good citizen to a naughty boy, and if more people did that the 2.4GHz spectrum would be even more polluted than it already is, and your wireless network would never work because everyone else's overpowered routers are introducing more noise into the channel you're trying to use.

All that said.... most of the third party firmware allows you to tweak the output power. The HyperWRT firmware is fairly close to the Linksys firmware. Sveasoft are a bunch of jerks (or maybe just one?), don't deal with them. OpenWRT is great, but requires Linux skill. There are other firmwares out there - check linksysinfo.org. Also check that you're running a good Linksys firmware - some of them for whatever reason set the power down way low.

Incidentally, most of the discussion of power and SNR applies to any wireless device, it's just that with most of them, you the user don't get to fiddle with such things.

 

[skyking]

nice post, cmetz. It goes along with the real world experiences I have had. I run several of those routers with 3rd party firmwares, and discovered that overmodulation is a bad thing
The power sweet spot with stock antennas is not more than 42Mw, which is much less than the mandated maximum 100Mw. The ideal power output is the minimal amount that gets the job done.

 

[kehi]

If I change the output power from 28mw(default) up to the 42mw, how much do you believe the range increases? I know this is dependent on environment but can someone give me an idea if the signal has got to cross plywood, no concrete or metal? Thanks


BTW: I bought two of the WRT54G routers from OD yesterday and I have set them up as bridges to connect two wired networks(no wireless clients). I tested them with the
DD-WRT v23 alpha software and they are functional. They are going to share a 4mbps cable connection. My regular download speed when using my wired connection is usually ~500kbps when downloaded from a good site. I know that throughout depends on distance but what speeds should I expect from the bridged side of the network compared to the ~500kbps from the wired(non-bridged side)? Thanks

 

[cmetz]

kehi, the problem is that signal strength is typically not the limiting factor in wireless networks, at least in my experience.

There's stuff that signal goes through, and there's stuff it doesn't. If your signal hits the latter stuff, you're more or less SOL no matter what gear you have. If you have none of that stuff, then you're restricted by distance, which is strength sensitive. So in my experience with higher end wireless gear (Cisco Aironet 1200), upping the power, or using high-gain antennas, typically buys you nothing. Because they solve a problem that's not the problem you really have. The problem you really have is that real buildings, and real houses, have objects that pretty much just block the signal. For example, in office buildings, the elevators just block you. No amount of power within reason is getting through those big pieces of metal. Similarly, houses are made out of a lot of wood, which is also fairly toxic to 2.4GHz signals (that whole water thing, look it up).

kehi, if you can establish a stable wireless link between two bridged WRTs, you probably will be able to get the 500kbps you're used to without much trouble.

 

[JackMDS]

Originally posted by: skykingThe power sweet spot with stock antennas is not more than 42Mw, which is much less than the mandated maximum 100Mw. The ideal power output is the minimal amount that gets the job done.

Since we are talking entry Level Hardware that might be variation even within unite of the same model.

I use 60mW into a "Big" 6dbi Omni (higher dbi and omni might be oxymoron but it is better built Antenna then the original ?Stick?).

SNR is good and range is excellent through two wooden walls and long backyard with a lot of wet Brush.

:sun:

 

[kehi]

I had everything working great at my apartment with the factory antennas installed and at 40mw. I mounted one bridge(connected to the wired router) in my closet high close to the attic space. I took the other bridge to my brothers place and installed it the same way and hooked it up through a 5 port switch. His computers where not able to obtain an ip from the wired router which lead me to believe it is not getting a signal down there to his place. I even turned to antennas up to 60mw each and nothing. As I mentioned before the config was working great in my apartment so I know it was setup properly.

What I am wanting to ask is what you guys think of This type of antenna. I know that I also have to buy the cable with it. My plans are to install one of these on each bridge and point them toward each other. Would this be considered 24dbi gain for too?

BTW: You can see my building layout at this thread. I think I will try putting the bridges up in the attic next, just hope to use POE. Thanks