A SHORT STUDY OF STACKED YAGI-UDA ANTENNAS
© Jay Terleski, WX0B
DISSIMILAR ANTENNA STACKS
It can be done with certain precautions
Example 3 ele with 4 ele 15 m:
3 feet / 44.4
ft (WL) X 360 degrees = 24.3 degrees of delay is required to put
these antennas in phase.
3 feet X .66 (VF of RG213) = 1.98 feet of coax would need to be added to the leading driven element.
Lets correct the model by adding in the del
Picture: PY5EG 10m H-frame stack
Issues with stagger types that turn:
Close coupling is a problem
Drive impedance vary widely as the array turns
Matching will b a problem - very difficult to adjust !
This type of array is probably not suitable unless everything remains fixed as in an H-Frame or parallel tower single direction
More work needs to be done on LAPA type arrays for amateur work
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