This is a great antenna for the 30m Band, super quiet on receive, good gain through the loop and will fit nicely into the average U.K. garden.
The antenna comprises of one long piece of 2.5mm wire 31.5028m long arranged into a flattened triangle. Wire 1 as shown above is exactly 14.5m long and must be exactly 1m above the ground. Wires 2 and 3 are 8.5014m long with the peak being exactly 5.44m above the ground.
The antenna is best fed via a 1:1 balun at one of the bottom corners (Shown by the circle in the image above.)
The antenna presents an almost perfect match to a 50 Ohm feed and so no other tuning is required.
I am currently using this antenna at my U.K. QTH, it’s unbelievably quiet on receive with noise being less than S2 making it very easy to hear even the most weak of DX station.
This antenna doesn’t have massive gain at 1.42dbi @ 26 deg but, being so quiet on receive makes it a great choice for the 30m band. It is worth mentioning that I rarely hear other U.K. or close E.U. stations on this antenna, this is most probably due to the large null in the centre which attenuates signals arriving from a high angle.
Most of the radiation is through the loop so keep this in mind when erecting the antenna.
With an almost squashed ring donut shape and a deep null in the centre, this antenna is superb for working weak signal stations on the 30m band.
This is the view of the 30m Delta Loop at my current QTH in the U.K. I made my own 1:1 balun and housed it in 40mm water pipe with screw caps, works a treat and never has any problems regardless of weather.
Summary:
Total Wire Length: 31.5028m
Horizontal Wire Length: 14.5m @ 1m above ground
Diagonal Wire Lengths: 8.5014m
Wire Dia: 2.5mm
Height at Centre: 5.44m
Feed Type: 1:1 Balun in bottom corner (Can use coax if necessary)
Impedance: 50 Ohm
SWR: <1.5:1 across whole band