Once all cables have been linked we reinforce it with adhesive. Thus, we have made the connections between cooper core and cooper core, cooper core and cooper shield, and cooper shield and cooper shield with the help of screw terminal as we have done previously. The connections between these cables are the same as we have illustrated in the Receiving antenna design polarization part. One of the last tasks, is to link the cable of each branch in one cable. One dipole of the Double Cross Antenna with the cable connection We have placed all of these components in the Tee pipe and add rubber top cap at the opposite part of the Tee to support and axe the both part of the dipole as the following picture depict.
These connections have been attached to metal support by an adhesive with the target to reinforce the strength of the links. We have repeated this operation with the up part of the dipole and the copper core. Once this two elements have been separated, we have twisted the copper shield and connected to the down part of the dipole with the help of screw terminal. As we have explained earlier, one part of the dipole needs to be connected with the copper core and the other part with the copper shield. We have started by stripping the cable for separate the copper core and the woven copper shield. The next step was the connections between the cable and the dipoles. The copper core needs to go in the center of the plug and be isolated from the copper shield. We have stripped the cable for separate the copper core and the woven copper shield. Thus, we need to use male/female coaxial plugs in order to part the cable.
We have made the choice to have a removable antenna. The difference of length is a proportional to a quarter wavelength in respect of the velocity factor of the cable RG58U. Thus we have had two cable with a length of 1.44m for the north and south side and 1.80m for the east and west side. Once the glue has dried, we have drill holes in the mast for passing the cables to the dipoles via the different branches.Īfter this last operation, we have cut the cable as we have presented in the Receiving antenna design polarization part. These elements support and connect the branches to the mast. Then, always with the 32mm diameter PVC pipe, we have sawed eight pieces for the T pipe PVC to support the dipoles.Īfter that, we have pasted four PVC pipe supports to the 100 mm diameter PVC pipe, which is the mast of the antenna. Secondly, we have cut four pieces of 32mm diameter PVC pipe with a length of 20cm to create the four branches of the double cross antenna. Indeed, our dipole is composed by a pair of metal rod. Once all the materials have been bought, we have started to build the antenna.įirstly, we have sawed the four 1 meter rods in two to obtain our four dipoles. Moreover, here we decided to use Male/female coaxial plugs in order to be able to remove each side of the antenna as we wanted a removable antenna that is easier to move and to store.Īdditionally to these materials, some specific tools and softwares are needed to be able to decode the APT signals: The aluminium rods can be replaced by any other conductive material.
List of materials with dimension and quatityĪll these materials are available in any supermarket with a plumbing section. Here is the main material needed to build the double cross antenna: Previous : Receiving antenna design Next : APT images reception Receiving antenna building ¶ List of components ¶