2019-03-20 08:35 AM
Hello. I am trying to establish a working wireless communication between two radio units using S2-LP components.
Both units are an S2-LP development kit which includes a nucleo-L053R8board with a mounted STEVAL-F433V2 board.
The code is the example project included in the S2-LP DK_1.2.1 software package.
The specific project compiled is the SDK_BasicGeneric_A.c example project in the
\S2-LP DK_1.2.1\Projects\Projects_Cube\S2LPLibrary_Examples\MDK-ARM\STM32L053R8-Nucleo
directory. (running on Windows 10).
It is compiled and flashed into the components using Keil uVision V5.26.2.0
The transmitter unit is flashed with the SDK_BasicGeneric_A.c code (transmitter code) and the receiver unit is flashed with the SDK_BasicGeneric_B.c code (receiver code).
The issue is, while I manage to establish a one-way communication, the range of reception is extremely limited. Any distance between receiver and transmitter beyond about one meter causes loss of reception. The receiver reports a maximum RSSI of -79dBm when transmitter and receiver are close together (zero distance) and a minimum RSSI of -112dBm at the edge of the reception range (about a meter).
Changing the datarate did not seem to have any significant affect on the range, and local interference was pretty much eliminated.
As this is a long-range 433MHz communication device, we would like to resolve the issue and increase the range (we need at least 100-150 meters of reliable communication).
What can be done to increase the range and bring it to it's maximum potential? Is there a need for external amplification on transmission? or should the settings be change to achieve full range? (attached is the file SDK_BasicGeneric_A.c (transmitter code) we are using.
2019-03-21 06:22 AM
Hi, Actually the STEVAL-FKI433V2 is not designed to do RF test range because it's ground plane is bad.
It does not reflects the real range the S2LP can achieve.
(FYI, STEVAL-FKI433V2 (433MHz) groundplane have the same size that the STEVAL-FKI868V2 (868MHz) and it's half the frequency. that's why).
By playing with the modulation/DR/FDEV/CHF you should increase the range.
With an other antenna, on a light of sight environment (without noise & obstacles) with : DR=38.4kbps : FDEV=20kHz : CHF=100kHz with modulation : 2-GFSK05 the STEVAL-FKI433V2 can reach up to 2.1km.
The antenna does impact a lot. The little antenna provided with your kit may be not matched @ 50ohm for 433MHz. You can change de antenna with one fully matched @433Mhz and it will increase by far the range.
2019-04-09 01:40 AM
Hi,
>> Any distance between receiver and transmitter beyond about one meter causes loss of reception.
One meter is really a short distance.
There must be a problem with the transmitter or the receiver.
Program the transmitting power to 0 dBm
If you have a spectrum analyzer, measure the transmitted power out of the SMA connector.
You will need a cable or an SMA to N adapter.
You should measure -3 dBm or something like that.
Ciao,
Enrico Migliore