I received several requests to make information available about the 137 Mhz Weather Satellite Equipment I use to download images from NOAA Weather Satellites. I will start with the antenna being used. I tried several antennas in the past which included crossed dipoles, yagi's, QFH antennas ect. They were all working but I was still plagued by loss of signal which resulted in stripes, lines and dots on the actual picture. I even went so far as to build a pre-amp to use with these antennas, but the pre-amp just amplified the problem. I came across an article written by Renè ZS1VR. He described how to homebrew (build) a Quad antenna for 137 Mhz. One of the pre-requisites for reception of a weather satellite images is that the antenna must have a wide-reception angle to eliminate the "null" areas as this ensures a clean and "interference" free picture.
Myself and Nico ZS4N constructed the antenna from ordinary 15mm copper pipe with copper and PVC couplings. 6 mm aluminum rod can also be used instead. Here is the list of material you will need to build the copper pipe version:
10 x 15mm copper elbow joints
4 x 15mm copper T-piece joints
2 x 15mm copper end-caps
1 x 15mm PVC T-piece joint
1 x 15mm PVC 4 joint power box
1 x 15mm Length copper pipe
1 x 15mm Length PVC pipe
1 x 20 x 50 mm Perspex
2 x 4 x 20mm Brass Bolts
4 x 4mm Brass Nuts
2 x Electrical lugs
1 x 1m 75 Ohm Cable ( The best quality you can get.)
1 x PL259 and barrel connector
1 x 1M Aluminum Pipe. (15mm PVC must fit snugly into Alu pipe.)
2 x U clamps
Cable Ties
I will not go into great detail here on how to construct the antenna as the photo's is self explanatory. The antenna exist of two elements. There is a driver element and a reflector element. Outside measurement of the driver element (quad) is 54.5cm and the reflector element is 57.6 cm. The spacing between the two elements is 41.0cm. Photos here under show the feeding point of the antenna. The two end caps are drilled and a brass nut is soldered into place. I use a 75 ohm matching stub with RG58CU Mil Spec coaxial cable. The matching stub length is a 1/4 wave length of 137Mhz.
Well this is the best homebrew weather satellite antenna I ever used. I received clean pictures with very little signal loss from the LOS. Will not use any other homebrew antenna.
