Sending your data through the air
What About Transmitter Range?
The Serial RF Pro is rated for 600 meters in free air (i.e., no obstructions along a line-of-sight path). Anything in your way reduces the received power and the range. To test the range, I took the solar-powered transmitter system on a walkabout (see Figure 7) and ran two tests: one with the receiver behind three interior walls and a single exterior wall and one with the receiver behind only one interior wall. I specifically looked for continuous data flow. I found that I could walk 5% - 10% further than the maximum reliable distance and still get a packet now and again. Putting my arm up in the air also increased the distance. Height really helps in this kind of a situation.
Table 1
Maximum Transmission Distance
Receiver Condition | Maximum Transmitter Distance |
---|---|
Behind 3 interior walls/1 exterior wall |
220m/720ft |
Behind 1 exterior wall |
438m/1,437ft |
Conclusion
Once again, I am amazed at what can be done with inexpensive hardware and, once I had the Grove Pro Mini LP built, how easy and fast it was to build the WXLink transmission system. I have run out of room in this column, but I have a lot more information on this project, some of which you can find at the SwitchDoc Labs website [12] including a lot more discussion about the solar-powered version.
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