Project Curacao2 – Part 3 – Testing the LoRa Range
Project Curacao2 is a redesign and rebuild of the Project Curacao environmental monitoring system that was running down on the island nation of Curacao in 2014 and 2015. It finally died after a loose wire in the solar panel assembly (not in the panels, but in the internal wiring) finally came completely loose.
We have one more step to do before we start building the base Raspberry Pi Zero Project Curacao2 base unit and that is testing the LoRa radio data range.
- Part 1 - Introduction to Project Curacao2 and the LoRa WXLink Feeder Stations
- Part 2 - First LoRa WXLink Feeder Stations Report
- Part 3 - Testing the LoRa Range
- Part 4 – Initial LoRa Range Results
- Part 5 – Final LoRa Range Results
- Part 6 - Raspberry Pi Zero Base Unit Build
- Part 7 - Flame On! Initial Base Unit Tests
- Part 8 - Solar Power Management System
- Part 9 - Ready for Deployment and Status
- Part 10 - PC2 in the Caribbean! Repairs and Testing
- Part 11 - It Lives! Deployment and Initial Results
- Part 12 - One Month of Results from Paradise
The LoRa Range Test Setup
Project Curacao2 has two LoRa WXLink remote stations. One on a tower located about 30 meters away from the base unit and one located about 1Km away from the base unit (the Ridge antenna for those familiar with the world famous Amateur Radio Station, PJ2T). We felt it would be interesting to get the two sets of wind speed, humidity and wind direction from both sites, hence Project Curacao2 was designed to receive information from two remote, identical LoRa WXLink units.
Before we go down 3500 miles to set this up (scheduled in early June 2017), we want to know if we need a better
antenna for the 1Km radio Ridge link. We could get significantly more gain from a Yagi antenna than our simple pole antenna at the cost of having to aim the antenna. But that’s a deployment problem for another day.
We decided to run a test by setting the LoRa WXLink boxes on top of the house and then put a GPS based Raspberry Pi in a car with a Grove LoRa Receiver and then go for a drive. We will change one of the boxes to transmit every two seconds so we get lots of data.
We decided to use a Raspberry Pi 3 processor on battery power using an Adafruit GPS with a Grove 433Mhz LoRa Transceiver (identical to the units in the LoRa WXLink boxes) with a normal dipole antenna (identical to the current LoRa WXLink boxes). We know we can make the 30m range to the local tower in Curacao (we have tested that range), but we don’t know if we can get to the Ridge. Because of the logistics of this deployment, we are getting a 433MHz Yagi antenna to take down with us as we don’t quite have a line of sight to the Ridge antenna, so we may need it anyway.
One thing we don’t show on the block diagram is a buzzer that will buzz every time it gets a good packet. That way we only need one person in the car for the test.
Here is the block diagram for the test setup:
We plan to mount the antenna outside of the car (to avoid the “Faraday Cage” effect) and then go for a drive, checking reception and saving the GPS coordinates every time we get a good packet from the LoRa WXLink (modified to send every 2 seconds). The software for the data gathering is pretty simple and will be discussed in the next posting. It basically checks for new packets with good checksums and then records the GPS location when it receives them. Going from the GPS coordinates in a text file to a Map will be a bit more complicated.
Results
We will be running this test sometime this week. We are specifically looking for range, but plan to place the data on a map in any case.