Any amplifier available for increasing transmit power to 3W or so as to achieve 1000 m using small antenna at receiver side? Antenna at receiver side will be located at LOS (Line of sight). Can any one recommend the suitable Antenna to satisfy my requirement?that Antenna Length should be proportional to the distance travel required.
For example, to transmit 433 MHZ to 1000 m distance,
The Antenna Length = 1000m/433 MHz = 2.30m = (2.30/4) (i.e lambda/4) = 0.57 m = 57 CM.
But, I can able to realize only up to 100 meters.RF SETTINGS: CFREQ= 433 MHz,
+/- 30KHz deviation,
datarate 1.171875 Kbps (1200 bps),
BW = 64.1 KHz,
IF = 937.5 KHz.
If you get at 100 m (max) the signal will be 100 times less (20dB) at 1000 m.
No. It is not in a fixed location. Slave (Receiver) is a hand held device. It can move around. If the Master (TX) find the Slaves (RX) within its region (Line Of Sight - 1 Km), it will send a message. But it does not need to wait for acknowledgement from slaves (so no need for higher powered antenna at RX end). It is one-way transmission only.If they are line of sight, presumably they are in fixed locations.
It is not possible to use bigger antennas in RX side. Because it is a hand held device.Why not make up the extra 20dB or so by using a directional antenna at both ends
lambda/4 tried. The result was only 100 m. I am going to try dipole (λ/2) antenna. I will post the result tomorrow.I would try with a real lambda/4 or lambda/2 antenna first.
It is not possible to use bigger antennas in RX side. Because it is a hand held device.
As calculation shows, there's a huge difference between the theoretical range and your tests. The question is, what are the shares of bad spiral antenna efficiency and matching losses, obstacles blocking line of sight, RF interferences reducing the sensitivity.A dipole will maybe give 100m -> 150m increase.
As calculation shows, there's a huge difference between the theoretical range and your tests. The question is, what are the shares of bad spiral antenna efficiency and matching losses, obstacles blocking line of sight, RF interferences reducing the sensitivity.
YesIs your link really line-of-sight?
case 1: 10 footHow high radios are above the ground?
RSSI = 0x54 approx when Both TX and RX placed between 1 foot. reading RSSI when RX receives signal from TX.What RSSI you get reported from your receiver at the fringe of the link?
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