ขายสายอากาศติดรถยนต์ COMET CA212H
ชนิด 1/2 แลมด้าความยาว 1.10 เมตรอัตราขยาย 2.15 dBi
จากแดนปลาดิบ มี 2 ต้นราคาต้นละ 1,500 รวมส่งลงทะเบียน
Power Output & Antenna Gain
The power output of the radio is in dBm and the gain of your antennas is in dBi.Gain is term used for measuring of increase in signal power, described in decibels (dB) which is a logarithmic measure of relative power. Gain is typically measured in dBi (decibels relative to isotropic radiator - a theoretically "perfect" antenna) and is based on decibels. The dBi is computed by comparing the output of the antenna to a theoretical isotropic radiator (antenna) with a dBi of 0: the higher the dBi measurement, the higher the power level of the antenna.
Antennas are designed to raise the power in the wanted direction and reduce it in unwanted directions.
To convert milliwatts to dBm :(0 dBm = power dissipated by a 1 mV signal into a 50W load)
dBm = 10 * (log (1000 * P))
P = Power in Watts
1000mW = 1 Watt
To convert dBm to milliwatts:
P = 0.001 * (10**(dBm/10))
P = Power in Watts
Calculator to convert dBm to watts and milliWatts
3 dBi gain antenna is equivalent to raising transmit power from 10 mW to 20 mW.
5 dBi ~ 33 mW,
8 dBi ~ 66 mW,
12 dBi ~ 160 mW,
15 dBi ~ 320 mW,
18 dBi ~ 640 mW.
