I am extending my network using 900MHz connectorised. At the base station i have an omni directional antenna MT-243003 NH; it’s a 11.5 dBi antenna.
At the customer end, i am using a 917A-ISP yagi antenna; it’s a 17dBi antenna.
I would to know how can i set my transmit power output for me to get a best performance of my antennas. For now i have 5 customers and i intend to install a new one at about 20miles.
Please i need assistance.
To maintain FCC compliance (assuming you are in the USA) your EIRP cannot excede 4 watts or 36 dB.
To achive this, set the transmitter output power to 36 minus the gain of your antenna. IE: 17 dBi Yagi… 36-17=19 so set the output power to 19.
Also to keep in mind, ideally you want the AP to register all of its SMs at an equal power level. To achive this, turn down the output power of subscribers who have stronger signals.
The theory is that a SM that is blasting the AP with -30dB will desensitize the receiver. Making it harder for the AP to pickup that distant customer with a -79dB signal.
This this becomes more of an issue as the number of SMs on an AP increases. For the first dozen subscribers, it will hardly make a difference. But 150+ SMs register to an AP, and you’ll see what I mean.
ahull, is there a way to mathematically figure out what I should set the transmitter output too?
Sure, the short answer is:
36 - [antenna gain] = output power
See my post above for the long answer