Lew G8KJJ 15m delta loop 

15 metre Diamond Loop

The 15 metre Diamond Loop described here is an adaptation of the 10 metre and 12 metre Delta Loop featured in earlier posts. Initially the project started with a 10 metre antenna, based on two 11 metre “CB band” telescoping aluminium vertical antennas. It was extended to the 12 metre band by adding additional sections to the 10 metre antenna. Both antennas provided low angle radiation suitable for working dx.

By adding a fibreglass fishing pole in the centre of the vee formed by the two antennas a diamond shape was obtained. The antenna was modelled using EZNEC Pro2 software. The modelling is simplistic and includes only basic parameters but gives an idea of how the antenna will perform. In reality, the SWR was a little higher than the model suggested at 1.6 : 1 at 21.150 MHz. The fibreglass pole is 6.4 metres in length and the top section of the diamond shape is 6 metres. All other dimensions are the same as the 12 metre Delta Loop.

In use the 15 metre Diamond loop worked as predicted by the model being good for DX but less so for short skip. The big advantage of this antenna is that the feed-point is only 3 metres above the ground and the antenna can be erected quickly and easily.