Construction of the mount for the 3.7M dish

The dish mount was build on a trailer (ex Belgium army), so it could me moved and eventually be used on dx-peditions. The elevation system had to be used to lower the dish flat on the trailer.The horizontal “U- bar” is about 100KG heavy and about 26×8 cm. This was reinforced using 6x4cm steel. The system is “balanced” by 4 concrete tiles.

The dish in almost full elevation. Note that the vertical “U-bar” is reinforced by 2 pieces of sheet metal triangles. The elevation rotator is a satellite actuator. The box at the rim of the dish is for the TWT power supply.

The rear view of the system.

Another view of the dish. Note the 2 extra legs of the dish made out of “builders supports” (used to support roofs etc.).
These are adjustable in height, easy to modify and easy and cheap to get.

The azimuth drive of the system. The same system is used as with the big dish. A chain drive 1 : 5 to minimize play. In the left under of the photo the pot-meter for readout. More is not needed. Once the moon is found, tracking is done on moon noise.

The elevation system is build around two 40mm bearings. You can see the reinforcing of the 2 U-bars better here. Again pot-meter readout.

The feed-system for the dish is build to fit a plastic barrel. The TWT is mounted directly to the feed.

Another view of the feed system. Preamps, an extra driver stage and power coupler are mounted on this side.

A 5 ring scalar feedhorn is used to illuminate the dish. It is designed and build by Walter HB9AGE. The scalar ring is adjustable on the circular wave-guide.


A drawing of the scalar feed.