110OhmDeltaLoops for 2 m, 4 m and 6 m (DK7ZB) (6mDeltaLoop for 50 Ohm see down)

The DeltaLoop has the parts B longer then A. The reason is a
little bit higher gain and an impedance of 110 Ohm. The
transformation to 50 Ohm is made with a quarterwave section of
75Ohmcable RG59 B/U. The spreader is a PVCpipe with 25 mm
diameter. The wire is PVCinsulated copper braid 1,5 mm^{2}. In the right picture you see two current maxima, the loop is a stacked system with a gain of 0,95 dBd. If the loop is configured for 100 Ohm we get a great bandwidth. The wires 2 and 3 are a little bit longer as wire 1 in that case. 
50OhmDeltaLoop for 50 MHz
The normal DeltaLoop has an equilateral triangle, it has
an impedance of 115 Ohm and a great bandwidth (1 MHz for SWR <
1,3). If we make the vertical wires
longer and the horizontal wire shorter (isosceles triangle), we
can reach a relation which leads to an impedance of 50 Ohm. The
gain is increasing a little bit (from 0,95 dBd to 1,3 dBd). So
we do not need a matching section and we can feed the DeltaLoop
with 50Ohmcoax directly. A simple commonwave choke is wound with 10 1/2 turns of coaxcable with 5 mm diameter on a 50mmPVCtube. The bandwidth is smaller and the circumference more critical. My antenna has a SWR < 1,3 between 50,0 and 50,5 MHz. I have built the 50OhmLoop with 1,5 mm^{2}PVCinsulated copperwire and a circumference of 612 cm. Other wires need a complete other length! But it is not complicated to tune the length of an individual wire (insulated or not insulated) with an SWRmeter. Here SWR with 5 m coax:

SWR measured in the feedpoint:
If the antenna is mount with a feedpointheigt of 10 m above ground we get a elevation diagram as follows: