TX Power adjustment, what is safe/stable?

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TFroehlich3
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PostPosted: Sun Nov 27, 2011 1:36    Post subject: TX Power adjustment, what is safe/stable? Reply with quote
I was just wondering, the default setting for the TX Power (antenna power) is set at 71mW and can be set all the way up to 251mW. Would anything go wrong if it was set all the way to 251mW? If so, what is a safe power setting other than the default?
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Murrkf
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PostPosted: Sun Nov 27, 2011 2:00    Post subject: Reply with quote
Router usually needs to RX as much as it needs to TX. Sort of like yelling, but being deaf.

Tx increases noise = diminished signal quality.

Tx can increase heat.

People often LOWER TX to increase throughput and stability.

Safe setting depends on router. See the first post in this forum.

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TFroehlich3
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Location: Kalamazoo, Michigan

PostPosted: Tue Nov 29, 2011 19:39    Post subject: Reply with quote
So would it be best to just leave the settings at the default 71mW?
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Handyman007
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PostPosted: Wed Nov 30, 2011 14:17    Post subject: Reply with quote
The only reason I could see to raise the Tx power is if you are using external antennae that have a long enough cable run as to cause a signal loss over the cable run.

I suppose you could also increase the Tx power if you have clients that are dropping connection because they think the signal coming from the router is too weak. I have done this and it has helped to an extent. The caveat is that part of the equation is how well the AP hears the client, too, and the only way to beef that up on the AP end is to get higher gain antenna(e).
Pjotr12345
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PostPosted: Wed Nov 30, 2011 14:59    Post subject: Reply with quote
The optimal Tx-power is the LOWEST that's still adequate for your needs. Better to reduce electrosmog than to increase it.

I've reduced the Tx-power of my own router to 5, by the way. On my laptops I've reduced the Tx-power of the wireless chipsets to 5 as well (only possible in Linux, as far as I know). Fine for my needs. Smile

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TFroehlich3
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Location: Kalamazoo, Michigan

PostPosted: Thu Dec 01, 2011 15:12    Post subject: Reply with quote
I understand. The walls in my place are just so thick. The router is located in my bedroom, and when I am sitting in my living room about 25 feet away, the signal is cut to about half. Hmmm, I suppose I will just have to invest in some hi-gain atenna's huh?
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Murrkf
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PostPosted: Thu Dec 01, 2011 17:37    Post subject: Reply with quote
TFroehlich3 wrote:
I understand. The walls in my place are just so thick. The router is located in my bedroom, and when I am sitting in my living room about 25 feet away, the signal is cut to about half. Hmmm, I suppose I will just have to invest in some hi-gain atenna's huh?


No. That would be foolish and likely counter productive. Read the "catfish" thread. Hi gain antennas are NOT more powerful. They are more directional and inappropriate for 25 foot distances.

Losing half signal is not abnormal or problematic in most cases. Spend some time reading to understand this.

Pjotr12345 wrote:
Off topic: please use black font. Colored fonts are for Christmas cards, not for a technical support forum. Evil or Very Mad


QFT. Bold is equally inappropriate.

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markiechan
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Joined: 20 Jun 2011
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PostPosted: Mon Jul 30, 2012 8:39    Post subject: Re: TX Power adjustment, what is safe/stable? Reply with quote
TFroehlich3 wrote:
I was just wondering, the default setting for the TX Power (antenna power) is set at 71mW and can be set all the way up to 251mW. Would anything go wrong if it was set all the way to 251mW? If so, what is a safe power setting other than the default?


Most consumer routers aren't designed to really go above 20dBm/100mW. And there are definitely diminishing returns above that level. Some companies like EnGenius/Senao specialize in higher power WiFi. The problem is most clients only transmit at 15-20dBm. So therefore, the ideal is probably right around 100mW/20dBm for most environments though in one large scale install I maintain, I'm running AP's everywhere between 17dBm (default as you noted on many APs) and 29dBm (EnGenius AP's designed for it, several high power client bridges attached over a large area - serving clients up to 500 meters away though a forest...).

As for safety, more power = more heat = more potential for damage. Also, more power = more distortion of the signal = more packet loss. I wouldn't go above 20dBm without good reason on equipment not designed for it. I also made an old AP with overheating issues stable by running it way down at 12dBm (16mW) but that's ridiculously little power, and the thing just got replaced ultimately.
Mangix
DD-WRT User


Joined: 04 Aug 2011
Posts: 367

PostPosted: Mon Jul 30, 2012 19:08    Post subject: Reply with quote
on one router I have, I get the best results with the txpower set to 15mW. I also have another one set to 25mW(lowest it will go). Best results there too. Low as possible is best.
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