20/15m (3/4 Elements) Delta Loop (Heavy Duty)

20/15m (3/4 Elements) Delta Loop (Heavy Duty)

A 3/4 Element Dual-Band Delta Loop Antenna for 15 and 20m


Product Code – 20M3-15M4-WWHEAVY

A 3/4 element Dual-Band Delta Loop for the 15 and 20m bands from our ‘Heavy Duty’ range. Manufactured from lightweight but extremely strong construction grade 6082-T6 Aluminium stock with a heavy duty boom. This antenna features 5 sections of 6082-T6 or *AA6082-T6 tubing on the 20m vertical sections and 3 on the 15m. The antenna includes 6.35mm Diameter Wide Multiplate Element Brackets for the 15m elements and 10mm A2 304 Stainless Steel element brackets for the heavier 20m elements.H/Duty Polyamide Element Clamps come complete with M10 Stainless Hardware. Antenna is supplied with all hardware including a boom to mast mount of either 50mm or 63.5mm(see below).

The design is a new design originally requested by an Italian ham who wanted a high performance antenna on both bands. On modelling, the plot on 15 is excellent with a high gain nearing 10.5dbi and a front to back of over 25db. When normalised to 50 ohms, the SWR across the whole 15m is nearly flat. On 20 the gain is over 9dbi, again with front to back of around 25db. The SWR bandwidth is low over the whole band never going above 1.5 to 1 over a 300khz bandwidth and only going to 1.7 to 1 at the lower band edge. In all cases the antenna can be set-up to the operators’ specific requirements, whether SSB or CW or ‘Bandcenter’.

Vortex again use our very simple but effective approach in order to secure the element top wires. By using marine grade stainless steel fittings, the strain is taken off the top wires to prevent failure. Additionally for the 20m loops a stainless steel supports bar is included to prevent the vertical arms of the elements from moving and thus potentially breaking the element bracket.

See info below for mechanical and electrical details

  20/15m (3/4 Elements) Delta Loop (Heavy Duty)

Band(s):  20m (14Mhz) and 15m (21Mhz)
Element Material:  6082-T6/*AA6082-T6
Element Brackets (20m): 304 A2 Stainless Steel 10mm Heavy Duty Element Brackets (x3)
Element Brackets (15m): 6082-T6 aluminium plates with stainless support bar (x4)
Boom Material:  6082-T6 box section aluminium
Boom Length:  9.6m
Gain:   15m – 10.4dbi, 20m – 9.08dbi
Front to Back Ratio:   Better than 24db on both bands
Feed:   Coax via SO239 sockets x2
Matching:   Vortex Gamma Match x2 (PTFE dialectric)
Rating:   3.5kw
Active Elements:   3 on 20m, 4 on 15m
Element Clamps:   Stauff (Germany) – heavy duty polyamide series
Loop Top Wire:   2mm copper clad steel
Antenna Weight:   64kg
Optional High Wind Element Support Kit: More info here
Hardware:   304/316 stainless steel

*If available