RF concept:

• dBm = 10log(mW/100 +30)
• dBi isotropic dBd = dipole are respective gain of anntena compared with isotropic/half-wave dipole antenna
• reference: 0dBm = 1mW, 10 = 10mw, 20dBm = 100mW
• Range: 6dB double (line of sight) 12dB in urban
• Antenna: More gain more directionality, cabels should short as possible; there are omni/directional

• Ideal range: good tx power + gain anntena +/- environment----->Conducted= only TXpower RF module, EIRP = effective - Isotropic Radiated Power (anntena+ tx power RF module).
• Over the same power, higher directive anntena high range (similar a lantern with adjust beam)

• Antenna considerations: -Shorter long between rf anntena-->better, max long cable =15m -High quality cable (less 20dB attenuation every 100m) -Place the antenna diferent height if there are already -Attenuation increases with frequency

• Fresnell zone: space electromagnetic wave dependence distance, frecuency, a formule permitt to see a radio; for example at 900MHz 16KM ratio neccesary is 29m

• Current consumption assumes 50% transmitter time.