high Tx Power kills d/l speed on WNDR3700v3

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darussiaman
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PostPosted: Thu Nov 04, 2021 1:05    Post subject: high Tx Power kills d/l speed on WNDR3700v3 Reply with quote
Hello.

I followed the "BCM Best Wifi Settings" sticky. However, I found that the recommendation there to use maximum possible Tx Power is counterproductive on this device: a Netgear WNDR3700 v3. The build is v3.0-r47495 mega (09/28/21).

I did an experiment to document it on both frequency bands, which you can see below. It's arranged sequentially from top to bottom and from left to right. That is, I first started testing on the 2.4 GHz radio with 251 mW, then 1,000 mW, etc. I believe 71 mW was the number I saw when I first edited this setting after a reset to defaults, so that's where that comes from.

The tests were done with me on my laptop sitting ~1 yard away from the router. All other settings were kept constant the whole time, and only the Tx Power was changed on a single radio between tests. I used speedtest.net for the tests, and after switching each setting I did the test 3 times in quick succession.

The outcome you can see is that on both radios the download speed is markedly higher at lower Tx Power, by a factor of 4 on the 5 GHz band.

****

I wanted to document this in case anyone else has problems with wireless speeds.

Also, I have some questions. Is this result peculiar to my device? Or could it be an issue with the build?

Lastly, what speeds should I realistically expect on this router?



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kernel-panic69
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PostPosted: Thu Nov 04, 2021 2:25    Post subject: Reply with quote
The settings of 40mW thru 71mW are in the sweet spot. I would actually have to look at the sticky to see what is likely not quite correct for your device...
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ho1Aetoo
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PostPosted: Thu Nov 04, 2021 7:48    Post subject: Reply with quote
@darussiaman

you sit 1m away from the router and think that 1W is a good setting?

haha

The transmitting power should be adapted to the distance between the router and the client and contrary to popular belief, a high transmitting power is not always better.

In small apartments and rooms, the transmitting power can be reduced significantly.

And a too strong transmitting power can also have a negative effect.
I also always test with lower transmitting power on 4m because the throughput collapses with a too high transmitting power.

anyone who knows anything about WLAN also knows this - it's not a new discovery.

In the interest of your own health, radiation should also be kept as low as possible.

WLAN, operates in the microwave range, especially in the 2.4Ghz range in which microwave ovens also operate.
You are exposed to a permanent microwave radiation of 1W which heats the tissue of your body.
Whether this is healthy in the long run (hundreds - thousands of hours) is up to you.
Especially at 1m distance.

for "short range" also 13dB = 20mW works well and not only on 1m distance


Last edited by ho1Aetoo on Thu Nov 04, 2021 11:59; edited 1 time in total
the-joker
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PostPosted: Thu Nov 04, 2021 11:05    Post subject: Reply with quote
ho1Aetoo wrote:
WLAN, operates in the microwave range, especially in the 2.4Ghz range in which microwave ovens also operate.
You are exposed to a permanent microwave radiation of 1W which heats the tissue of your body.
Whether this is healthy in the long run (hundreds - thousands of hours) is up to you.
Especially at 1m distance.

for "short range" also 13dB = 20mW works well and not only on 1m distance

Ive experienced the exact issue when testing higher transmit power on the 5GHz band, from interference to distortion alone was a fun experiment, and coverage was not improved at all or signal strength at all improved. It really depends a great deal on specific environmental factors how well wifi works, even if two different ppl are in a room with 4 walls, the rooms walls materials matter for instance.

And also, yes, most microwaves are around 2.4/2.45GHz but you cannot compare how radio/microwaves work based on the frequency. Microwave ovens have different technology to achieve cooking, something the wlan radios dont have for one.

However, I would still not like to be sat next to a 1W wireless radio, for 10/12 hours a day for many years in a row, that's for sure.

Each to their own.

Be well.

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ho1Aetoo
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PostPosted: Thu Nov 04, 2021 12:13    Post subject: Reply with quote
It is also known from cell phones that the antennas heat the tissue of the head (SAR value). Wink

The amplifiers of the radios must be able to process the high signal levels without interference.

Otherwise they can overdrive (similar to an overdriven and distorted microphone)

So 1W high power is at 1m distance certainly not a good and sensible setting.
kernel-panic69
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PostPosted: Thu Nov 04, 2021 15:07    Post subject: Reply with quote
"Anyone who knows anything" knows that 71mW or thereabouts is the default and 40mW is an optimal setting on Broadcom Rolling Eyes
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darussiaman
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PostPosted: Thu Nov 04, 2021 17:00    Post subject: Reply with quote
ho1Aetoo wrote:
@darussiaman

you sit 1m away from the router and think that 1W is a good setting?

haha

The transmitting power should be adapted to the distance between the router and the client and contrary to popular belief, a high transmitting power is not always better.

In small apartments and rooms, the transmitting power can be reduced significantly.

And a too strong transmitting power can also have a negative effect.
I also always test with lower transmitting power on 4m because the throughput collapses with a too high transmitting power.

anyone who knows anything about WLAN also knows this - it's not a new discovery.



I hope it was therapeutic for you when you got all that sarcasm/attitude out of your system Laughing

If it's not a new discovery, why is the sticky at the top of this forum (posted less than 1 year ago) telling users to use 1 W of Tx Power?



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ho1Aetoo
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PostPosted: Thu Nov 04, 2021 17:35    Post subject: Reply with quote
Yes, this is the setting for the maximum transmit power.
The actual value depends on the regulatory domain and the hardware of your router.

Since the router is a bit older and does not have the best hardware, it is possible that the hardware limit for the TX power is significantly lower (the wiki says something about 251mW as the maximum TX power).

The actual deviating value should be in the WebIF ( Tab > Status > Wlan)

I also don't know why "msoengineer" thinks that you should always use the maximum transmitting power
This makes no sense at all with capable hardware and depending on the usage scenario.

E.g. if you sit 1m away ...
Or with a ceiling installation in a 30m² room

there you never need in life 1W transmitting power
in your special case it would still make the most sense to disable the WLAN and take a 1m LAN cable.

BS is of the same opinion, by the way, he wrote somewhere here in the forum that you can never have a quality connection with such a strong signal in your life.

BrainSlayer wrote:
sound all just like a incorrect setup. and if i see a snr of 50 and above, its clear that the signal is fucked up high and cannot be with good quality. its like your client i 1 meter away from your ap.
kernel-panic69
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PostPosted: Thu Nov 04, 2021 17:36    Post subject: Reply with quote
darussiaman wrote:
I hope it was therapeutic for you when you got all that sarcasm/attitude out of your system Laughing

It's the German male thing. Take it with a grain of salt and fry it like chicken.
darussiaman wrote:
If it's not a new discovery, why is the sticky at the top of this forum (posted less than 1 year ago) telling users to use 1 W of Tx Power?

Any way I comment here is going to have folks cross at me, so I shall relent to conceding.

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darussiaman
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PostPosted: Thu Nov 04, 2021 17:56    Post subject: Reply with quote
Well, I'm glad we're all on the same page now. Thanks for confirming.

ho1Aetoo wrote:

WLAN, operates in the microwave range, especially in the 2.4Ghz range in which microwave ovens also operate.
You are exposed to a permanent microwave radiation of 1W which heats the tissue of your body.
Whether this is healthy in the long run (hundreds - thousands of hours) is up to you.
Especially at 1m distance.


Also wanted to drop a comment on this. It's kind of a moot point since we all agree now that there's nothing gained from using 1 W, but I just want to say that there should be nothing to fear at 1 W in any case. The typical microwave oven is like 900 W, and the space inside the over is < 1 m. The radiation there is also concentrated in that space, which is far different than radiation diffusing in a 3D sphere. (Even if it's not really spherical from a router it's still not concentrated like a laser beam.) We also all use light bulbs all around us which are well over 1 W. Even if this microwave-spectrum radiation did noticeably heat our tissue (which would require more than just 1W), that by itself shouldn't be of concern--otherwise how would our bodies deal with all the times when we're outside in the sun and the sun heats up our skin?

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darussiaman
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PostPosted: Thu Nov 04, 2021 18:05    Post subject: Reply with quote
ho1Aetoo wrote:

The actual deviating value should be in the WebIF ( Tab > Status > Wlan)


Oh yes, I forgot to clarify, I did check that status page every time I changed the power setting to confirm that it was actually outputting that much. This router doesn't even give me the option to select regulatory domain. The wiki saying that max is 251 mW, I believe, is if the US regulatory domain is taken into account. But I don't have that section of "Country Settings" at all in my Wireless > Basic Settings page, so I guess it's unrestrained. I also see options for wireless channels that I'm not supposed to, like up to channel 14 on the 2.4 GHz radio.

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ho1Aetoo
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PostPosted: Thu Nov 04, 2021 18:07    Post subject: Reply with quote
kernel-panic69 wrote:
It's the German male thing. Take it with a grain of salt and fry it like chicken.


a joke comes to my mind

@kernel-panic69

How is Texas any different than Afghanistan?

The Afghans have more reliable electricity and are smart enough not to eat horse dewormer.

Laughing
itwontbewe
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PostPosted: Thu Nov 04, 2021 18:37    Post subject: Reply with quote
..

Last edited by itwontbewe on Tue Nov 09, 2021 2:10; edited 1 time in total
ho1Aetoo
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PostPosted: Thu Nov 04, 2021 18:46    Post subject: Reply with quote
you might want to read the FCC documents to see what radiation levels are specified for routers.
and also the manufacturer documents for "RF Exposure" there is for each router an absolute minimum distance specify

something like ~40cm
and 1yard is maybe the double

no one is stopping you from putting the router under your pillow
maybe it helps
ho1Aetoo
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PostPosted: Thu Nov 04, 2021 19:16    Post subject: Reply with quote
darussiaman wrote:
--otherwise how would our bodies deal with all the times when we're outside in the sun and the sun heats up our skin?



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