I was at one time quite active on the early OSCAR satellites. In those days (I’m going back over 35+ years) it was 2m to 10m linear transponder(s). Having not done anything with satellite communications for such a long time I decided it was time to see if I could hear myself via one of the latest CubeSats that uses a 70cms to 2m transponder.
To do this I needed a small 70cms antenna that could be pointed at the satellite. I already have suitable antennas for the 2m down link. Now there are many web-sites that describe how to make a suitable antenna and so I don’t propose to repeat that here, but what may be of interest is how I constructed the driven element (DE).
This yagi antenna was based on the K5OE Handitenna and constructed using 4mm aluminium welding rods and 21.5mm PVCu overflow pipe plus a T-piece. All the original element lengths, build details etc. can be obtained from the amsat-uk web-site.
My implementation of this design makes use of two ”Choc-Block” connectors to attach the coax-cable pigtails to the ends of the DE folded dipole. The brass screw-connector pieces, which were removed from the plastic insulation block, are soldered directly to the coax-cable and then pushed through holes made in the PVCu T-piece. The following photos show the idea.
This method of construction allows the coax-cable to run back inside the PVCu tubing. Epoxy type adhesive was used to secure the elements in place.
The finished antenna works well and yes, I have tried with one or two of the current satellites and successfully heard my signals coming back on the down link. 🙂