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laithmikrotik
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The Tx power of the mikrotik wireless interface

Wed Nov 14, 2018 12:52 pm

hi every one
there are 4 options in the tx power mode of the wireless interface /
1- default
2- all rated fixed
3- card rates
4- maunual
the question is about the options 2,3,4..
in which case we have to change the number value that shown in options ?
with thanks
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WeWiNet
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Re: The Tx power of the mikrotik wireless interface

Wed Nov 14, 2018 5:04 pm

If you use a wireless AP you should use "regulatory domain" and select correct country to respect local regulation :-)
And not change anything else.
If you use external antennas/PtP links etc. you want to play with the output power at modulation rates.

With 17dBm max output power you can not do much (I assume this is a hap lite or small AP product integrated antennas).
With such a product you can lower the output power to reduce interference if you have couple of Wifi AP close buy.
Or say on AP that only needs to cover a conference room, or reduce radio "smog" :-)

Playing with output power makes more sense / is required with high power devices where indeed you might not need all the power
or you have high or low gain antenna that you want/need to match over data rates.

PS: If the HW provides you max 17dB, you can put in 35dB, but it won't change anything and reset to the 17 value
PSS: If the client does only have ~17dB output power on his side (such as phones , tablets, which have even less in high data rates) there is
no need/benefit to further increase AP output power, as the client won't be able to reach back to the AP over distance.
In that case only increased receive sensitivity will help, via for instance 4 chain Wifi radios... (such as RB4011!), beam forming etc.
 
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laithmikrotik
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Re: The Tx power of the mikrotik wireless interface

Thu Nov 15, 2018 8:37 am

thank you very much for your replay :D :D
indeed, im asked about another concept . if you have any access point with 1000mw tx power .How can you reduce the tx power 1000mw to 500mw ? which value you have to change? is the reducing of the tx power manually have bad side effect on the access point performance ? :?
that is all in the matter
 
r00t
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Re: The Tx power of the mikrotik wireless interface

Thu Nov 15, 2018 10:23 am

Don't use "all rates fixed" unless you really know what you are doing and have equipment (spectrum analyzer) to see the resulting signal. Reason is that more complex modulations (ie. higher MCS levels) require more linear power amplifier and as a result, it can't be driven as much as when using simple BPSK/QPSK on low speed levels. Card knows these safe values and will limit power accordingly to not distort the signal (and essentially turn AP into jammer), this is what "card rates" mean. In this mode, when power is too high, card will limit it to safe level.
So if you want to lower the power relative to max allowed one by the card, start by using "card rates" and set it to high value (say 40.. card will clamp it down). Then in Current TX power tab you can see actual values card supports and you can adjust them down as needed. Values are in dBm, change of -6 dBm means halving of the original power.
 
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Petri
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Re: The Tx power of the mikrotik wireless interface

Thu Nov 15, 2018 10:37 am

r00t gives good advice. I would like to correct just one detail: -6dB is a quarter of the original. -3dB is half.
 
PainSama
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Re: The Tx power of the mikrotik wireless interface

Thu Nov 15, 2018 10:47 am

I am also facing this issue, i am not sure how to solve it but my diagram shows that clients dont enough signal from the APs (metal 2shpn) any way i can boost or change the tx or signal?
attached is my WISP AP page
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