by Mark Gilliam
I frequently fly my paraglider with several of my friends at Eagle Rock near Roanoke, Virginia. Like most flying sites, there is no weather reporting at the site. Pilots would look at the local weather forecast, then drive to launch. Sometimes conditions were as expected or better. Sometimes they were not.
I got to thinking about all the times pilots had wasted a drive to the mountain, only to find that the conditions were not as forecast. The money spent on gasoline alone could pay for a weather reporting station. So I researched what we would need.
We needed similar hardware that a desktop computer station requires:
1) Computer
2) Router
3) Internet modem
4) Internet provider
5) Electrical source
We also needed a weather station:
6) Transmitter (shown below)
7) Receiver
8) Computer software to send the information to the Internet
There were a few difficulties. There was no electricity or Internet available. We definitely did not want some bulky desktop computer sitting somewhere on the mountain. We needed a small, inexpensive way of setting this up.
I first tackled the two hardest items.
Item 5 above--Electricity. After researching the other hardware, I determined that everything could run on 5V, through USB connections. That simplified things. So I needed a solar panel, solar controller (to regulate 12V from the panel and charge a battery), 12V battery, and a 12V-to-5V converter.
Items 3 and 4--Internet. The only option was cellular Internet, so I needed a cellular modem and a monthly service.
I next researched the needed software (Item 8). The other components would depend on its requirements. I found that Meteobridge was widely used and supported many popular weather stations. I purchased a TP-Link TL-MR3020 router, because it could be reprogrammed (flashed) to run the program. So this router was now actually the computer (Item 1). It was only 3”x3”x1”, tiny compared to a desktop.
I next needed a second TL-MR3020 to act as a router (Item 2). I purchased a USB 3G modem to plug into it (Item 3). I got a Straight Talk SIM card (AT&T service) for our Internet service (Item 4). It all sounds complicated, but it goes back to the desktop computer station requirements--computer, router, and Internet modem/service.
So the computer system was done. The first TL-MR3020 was the computer (running Meteobridge). The second TL-MR3020 became the router. The USB modem with SIM card was the Internet access.
Now the weather station itself (Items 6 and 7). I needed a weather station that transmitted wirelessly to its receiver. Unfortunately, a secure structure for mounting the receiver unit and connecting it to the computer was 1000 feet away. Not many weather stations can transmit that far. Most are limited to 300 feet. A Meteostick receiver would have been ideal for size as it is no bigger than a memory stick, but it too is only good for receiving within 300 feet.
There are several weather stations for less than $100, but our distance requirements required a more expensive station. So, I used the Davis Vantage Vue. The Davis Vantage Pro would work as well, but was more expensive. Both are rated to transmit 1000 feet. In my tests, without obstacles, they were reliable to over 1500 feet. With the help of a fellow pilot, Carl Dennis, we mounted the station transmitter on a high structure.
Everything was then placed in a waterproof box called a SockitBox. Because of the size of the receiver and the battery, it took the large box, approximately 16”x13”x6”. In the box, I enclosed all the computer equipment, battery, and weather station receiver.
Back to solar power. During the day, in most cases, the solar panel powers all the hardware. At night, the battery does all the work. To minimize the solar panel and battery requirements, it was decided to only run the station during the day. So I connected a delay relay to turn off the equipment at night. With this setup, I only needed a 50W solar panel. I elected to get a large battery, 18amp. I calculated that the station could run for several days on a fully charged battery if we had continuous dark stormy days. This setup was probably more than we needed, but it was not too expensive, and the solar panel can completely charge the battery in only a few hours on a sunny day.
The last thing was handling and disseminating the weather data. I had the Meteobridge software send the data to Weather Underground. Setting up a weather monitoring page is free, but for a small cost (I think it was about $15 for several years), additional options are available. I also sent the data to our website and created a Webpage. I programmed this myself. After working out a few bugs in my programming, the station has been working great for several months.
What about maintenance? The Davis weather station runs off a solar panel and a backup battery. The battery ($5-$7) can be purchased at most stores and has a 2 to 3-year lifespan. The battery for the solar panel is the same used in most UPS backup power supplies. It will probably need to be replaced every 2 to 3 years as well.
So what was the cost?
1) Computer: TP-Link TL-MR3020, $29 on Amazon
2) Router: TP-Link TL-MR3020, $29 on Amazon
3) Internet modem: $20 on Amazon
4) Internet access: $15/month for 1GB service (only using 200-400MB)
5) Solar panel $90, solar controller $20, 18amp battery $40, 12V-5V converter $5, delay relay $10
6&7) Weather station transmitter/receiver and data-logger, $185 used ($400-500 new). This cost could have been under $100 with other stations.
8) Meteobridge software license, $75.
9) SockitBox, $20, and lots of miscellaneous wires and adapter cables, about $40.