Practical_Antenna_Handbook_0071639586

C h a p t e r 1 3 : C u b i c a l Q u a d s a n d D e l t a L o o p s 325
Boom
Mast
Figure 13.7 Single-band two-element quad on a boom.
Delta Loop
At frequencies below 14 MHz, spreaders and supports for fixed or rotatable multielement
quads become impractical for most amateurs. For some, the fixed delta loop is a
practical form of multielement parasitic array for the 30-, 40-, and 80-m bands.
The delta loop is a triangular or three-sided 1l loop. Although the ideal configuration
for a delta loop is with the horizontal side of the triangle at the top, this is usually
practical only at VHF. Instead, turning the loop upside down allows it to be suspended
from a single high support in return for a slight reduction in performance. Rope or wire
catenaries between tall trees are a popular way of supporting the delta loop, but a twoelement
40-m delta loop can be suspended from the ends of a 20-ft aluminum boom
attached near the top of a tower that is 70 ft or more tall. The approach has also been