DAT 75: Installation for vertical polarisation
Hi! DAT75 leaflet indicates that there is an additonal arm for installing the aerial to receive vertical polarisation. Nevertheless, there is no illustration about it. Can you help me?
DAT-75 Yagi antenna is a high gain aerial that is usually used for situations where both high gain and directivity are needed.
Due to the size of this aerial it is recommended that you take into account some precautions when installing it.
- Horizontal polarisation
In the leaflet supplied with the antenna it is explained how to assemble the aerial and where the clamps must be placed in order to secure the antenna to the mast.
- Vertical polarisation
To ensure secure mounting in this polarity it requires an additional off-set arm, reference 3012.
In this document we will illustrate the final assembly of both references 1097 (DAT75) and 3012 to the mast.
- Clamping to the U-bracket
First of all, never mount the antenna as show this picture.
From a mechanical point of view the clamp is weakened because of the torque produced by the weight of the antenna itself.
The U bracket used to reinforce vertical mounts is too weak to support the whole assembly.
Wind and weather conditions will most likely break the U bracket.
- Mounting the antenna in the central boom thus distributing the weight to both sides.
Mechanically this is acceptable, but from the electrical point of view it is NOT ACCEPTABLE because of the gain loss produced by the mast: up to 2 dB.
- Finally, we recommend mounting the antenna using the additional off-set arm, reference 3012. The final assembly will look as shown in next picture.
The robust arm ref 3012 will support the antenna in any weather conditions.