Weather Satellites by Sam, WA3UMC

RECEIVING WEATHER SATELLITES        

There are two types of weather satellites in orbit that we can receive weather photos from directly. There is the GOES (Geostationary Operational Environmental Satellites) satellites which are in geostationary orbit and transmit on 1691 MHz. And the other type is the POES (Polar-orbiting Operational Environmental Satellites) satellites. The POES satellites are in a polar orbit (each orbit of the satellite crosses both poles.) about 600 miles above the earth and transmit on 137.5 and 137.62 MHz. These satellites are operated by NOAA (National Oceanic and Atmospheric Administration).

On the following pages we will provide some photos and information on building a suitable receiver to receive the polar orbiting satellites from a kit. The receiver that I have built is an RX2 which is sold by RIG (Remote Imaging Group). Photo #1 shows the kit as it arrived.

The kit contains the PC board and all the components to build the receiver. You will have to supply your own enclosure and a signal strength meter. There is also an optional serial interface to add computer control although this is not required to receive the satellites.

Photo #2 is the signal strength meter I purchased from Grove Enterprises.

After receiving the meter I designed a new faceplate in CAD. I then printed the design out onto Avery label stock and cut it out. I then applied the label over the existing faceplate. Here is my new signal strength meter. Photo #3.

The next step was to build the receiver. This is a very straight-forward process of installing the components and soldering them. I chose to install the small components first and work up to the larger ones. Photo #4 shows the receiver with all the components mounted.

Next I chose a plastic enclosure from PacTec. Although the switches and jacks are supplied with the kit I chose to use some of my own. The nice thing about using the plastic enclosure is that the front and back panels are removable which make it easy to cut and drill for the controls. Photo #5 shows the front and back panels with the cutouts and the top with the drilling for the speaker.

I elected to do the same with the front and back panels as I did for the signal strength meter. I drew the faceplate and back plate in CAD. Once they were to my liking I then printed them out onto Avery Label stock. I cut them out and applied them to the panels. After applying the labels I then sprayed them with Krylon Clear to protect them. The finished panels are shown in Photo #6.

It’s now time to move on to the final stage of wiring everything up. Before we mount any of the controls or the circuit board we sprayed the inside of the enclosure with MG Chemicals conductive coating.

This will help shield the receiver from EMI/RFI. We now mount the circuit board and all of the controls. After everything is mounted all that is left is to wire everything up. Photo #7 shows the receiver all wired and ready to go.

        Photo #8 shows the front of the completed receiver and Photo #9 shows the back.

Photo #10 shows the receiver connected to the power supply and antenna with a nice strong signal coming in on 137.50 MHz.

The audio is fed from the audio out on the receiver to the line in on the Sound Card in your computer. There are several very good programs available on the web for recording and processing the information.

One such program is Satscape which is a free program that will allow you to view when the satellites will be coming over your location (Photo #11).

You can also track the satellite on a world map as shown in Photo #12 which shows NOAA17 on a near overhead pass.

Satscape will also record the audio from your receiver as a wav file to be decoded by another program. Here is a small audio clip from the NOAA17 pass. Another great program for tracking the satellites is WxTrack. Photo #13 is a screen shot taken from WxTrack.

To decode the information I use two pieces of software, WXtoImg and Satsignal. Both programs do a great job but each has their own unique features. Photo #14 is the raw image that was produced using WXtoImg on the NOAA17 pass as shown in Photo #1.

There will always be two pictures side by side. During the day one picture will be a visible light and one will be IR. At night both pictures will be IR. In Photo #15 we stripped away the IR and contrast enhanced the visible light photo.

 By combining the information in the visible light and IR photos you can create a false color image that is pretty realistic as seen in Photo #16.

By the way, this is all done with just a few clicks of the mouse. In Photo #17 we ask the program to add Latitude and Longitude lines as well as the State boundaries. The resolution of the photos is approx 2.5 miles per pixel.

The antenna that I am using is a Quadrifilar Helix Antenna that I built. Photo #18 is a picture of the current antenna.

This antenna does a fairly good job but has a few nulls in the pattern. So in the next couple of weeks we hope to begin building a new antenna. The new antenna will also be a Quadrifilar Helix Antenna but of a slightly different design. We will be photographing the building process and update these pages with the progress. We will also be setting up a receiving station for the GOES satellites. We are using a 10’ dish with a 1691 MHz feed horn feeding a down converter. The down converter will convert the 1691 MHz signal to 137 MHz which we will feed into the RX2 receiver.

This is just a small insight into receiving the weather satellites. If this has sparked an interest here are a few websites that contain a wealth of information on equipment and software.

http://www.geo-web.org.uk/index.html

http://members.surfeu.at/gerald_ihninger/

http://www.alblas.demon.nl/wsat/index.html

http://www.savannah-weather.com/

http://www.qsl.net/n8imo/wefax.html

http://homepage.ntlworld.com/phqfh1/qfh_diy_guide.htm

If you have any questions you can contact me at sharbold@comcast.net and I will do my best to help.

73’s
Sam
WA3UMC