15m Band Delta Loop Antenna

This is a 15m band delta loop design that I’ve put together as requested by Wim, PE1PME.

The 15m band delta loop follows exactly the same design principles as all the other delta loop designs I’ve already put on the website. They are designed such that they present a 50 ohm impedance at the feed point and thus have no requirement for complex impedance matching circuits/transformers.

15m Band Delta Loop Antenna View
15m Band Delta Loop Antenna View

The dimensions for the antenna are as follows:

Wire 1 – Horizontal exactly 1m above the ground for its entire 7m length.
Wires 2 & 3 are exactly 4.12m long each with the top being 3.18m above the ground.

15m Band Delta Loop Antenna 3D Far Field Plot
15m Band Delta Loop Antenna 3D Far Field Plot

The 3D far field plot shows a typical delta loop radiation pattern with the maximum radiation through the loop and a deep null in the centre.

15m Band Delta Loop Antenna 2D Far Field Plot
15m Band Delta Loop Antenna 2D Far Field Plot

The 2D elevation plot shows that the antenna will give a maximum gain of 1.5dBi at 26 degrees with useful gain at lower angles.

The SWR plot shows that the antenna will have a fairly wide bandwidth and match to 50 ohm coax extremely well. The antenna is designed to be fed in one of the lower corners via a 1:1 balun for best results.

15m Band Delta Loop Antenna SWR Curve
15m Band Delta Loop Antenna SWR Curve

Summary:

Total Wire Length: 15.24m
Horizontal Wire Length: 7m @ 1m above ground
Diagonal Wire Lengths: 4.12m
Wire Dia: 2.5mm
Height at Centre: 3.18m
Feed Type: 1:1 Balun in bottom corner (Can use coax if necessary)
Impedance: 50 Ohm
SWR: <1.5:1 at resonance