Can’t find any definitive information on this, so would be grateful if someone in the know would point me in the right direction. I have a RB912UAG-5HPnD that is causing adjacent channel interference with a colocated radio and would like to try turning down its txpower (all its clients have rx signal in the -50’s). The doc suggests I need to use power mode == “all rates fixed”, then specify a tx power value in dBm. However, I have no idea what value to supply such that tx power is reduced, say, 6dB vs the default.
Hmm…that makes no sense to me. Can you explain further? To clarify: I want to set the tx power to , say, 6dB lower than the default. How can the regulatory restrictions possibly match my goals here (except by coincidence)??
There is a sense, belive me:
You are trying to do something with tx-power because of interferences, but I’m answering you how to make it better So do not try to just lower the signall with all-rates-fixed, it’s half-measure method to set it wright, especially inside buildings.
“Antenna-gain” in dBi is used to calculate maximum transmit power according to country regulations. If you set antenna gain, country, and tx-power to default, all power’s for rates will be selected by Routeros.
But answering to your question directly: if you enable radio, which is set to default tx-power, than you can check actual tx-power in “Current Tx Power” tab. My solution is better than all-rates-fixed, because rates will have it;s own power values.
Still not making sense unfortunately. I’m not interested in setting txpower to some random value determined by the phase of the moon and regulatory requirements. I want to set it to an actual power output value in the realm of engineering and physics
The moon has nothing to do with your network. Just try the solution czolo gave to you. To better understand it when you set antenna gain ros thinks you have a more powerful antenna and decrease the power on the wireless chip to maintain country regulations. But you will have the same antenna and with the output power decreased it will make what you want. You can try with 1 db step to increase antenna gain until your output power will not interfere with others…
Just try my solution. More faith in engineering and physics, because my answer based on that. After the try, when you see the results, think again read “kiaunel” post below and try to understand how it works.
Thank you. I would never have understood this without your explanation. To help anyone else finding this thread in the future, here’s what I think you’re saying:
There is no good/easy way to control the power output on this board. Instead the best workaround is to enable regulatory compliance mode. This is done not for the purpose of complying with regulatory needs, but rather because it has the side-effect of enabling the “antenna gain” parameter. This in turn allows you to specify different purported antenna gain values (that have nothing to do with the actual antenna gain). RouterOS subtracts the supplied antenna gain value from some notional EIRP derived from its regulatory regime data and adjusts the radio txpower accordingly. Thus, you can by specifying increasing “antenna gain” values, effect a corresponding reduction in txpower. This approach is superior to simply specifying a single txpower value using “all rates fixed” because it preserves the txpower vs modulation rate relationship (txpower should be higher for lower symbol rates).
Did I get all that right?
What I still don’t know is how to know what magical information is in the regulatory domain data. Unless I’m an expert on all that (it seems complex – txpower depends on the channel in the USA for example), it seems I’m never going to be quite sure what txpower value will be selected.
So do not try to just lower the signall with all-rates-fixed, it’s half-measure method to set it wright, especially inside buildings.