Good day, John (KF0M) and others;
I was away all last week, and part of the previous, so I was
unable to give you a PROPER reply to your comments. Others had
comments to add to my situation, but none really had as good of a
reference as you!
From your data on my "assembly" of two DB224 antennas as a DB228
array, I will make the phasing harness up with a 1/4 and a 3/4 wave
(after the velocity factor computation of my RG-11 coax).
I have a few other related questions, if you would please allow:
MY QUESTIONS:
1. Is the FACTORY-MADE harness made up as with the RG-11 type coax
cables MOLDED onto the coax cables? -Or, are the cable "legs" simply
made up, then attached to a coax-TEE? (I want to make my own harness,
you see. It is my plan to solder the RG-11 coax directly to the
required type N connectors.))
2. It is my desire to have the top-most DB224 act as a bi-directional
antenna. As such (with no real info), I have arranged the top-most
two elements so that they are directly in line with each other. The
lower two elements are also directly in line with each other, but they
are are on the opposite side of the mast. (Elements 1 and 2 face
North; Elements 3 and 4 face South.)
Or, should elements numbered 1 and 3 be facing North (as an
example) and elements number 2 and 4 be facing South?
-I have NOT put the new DB224 up, yet.
3. I have no concrete plans for the lower DB224; It could remain as a
360 degree coverage, or I could set it up with elements 1 and 4 at
North and South, respectively; Elements 2 and 3 would then "span" one
side of the mast, soas to offer more of a carderoid (sp) pattern. -In
this case, the elements would face 0, 60, 120 and 180 degrees. (Your
suggestion, please?)
4. It is my ASSUMPTION that the top-most DB224 be "right side up,"
and the lower DB224 be mounted upside-down. Is this correct?
If this is the case, the lower DB224's elements will be "hot side
down," which is opposite from how the top-mounted DB224 has the
elements arranged.
If I mount the lower DB224 upside-down, will this retain water,
which will freeze and damage the antenna? (Yes, the 1/4 and 3/4
wavelength phasing harness will insure a proper phase, so I will
actually realize GAIN.)
5. The SPACING of the elements is far from "even; In my case, as well
as other reported element arrangements, I see from 60 to just over 70
inches of center-of-element to the next like point. I had fully
expected to see an exact measurement! I have a Cushcraft 4-bay
antenna, whose setup has all four elements at a fixed, and EQUAL
number of inches, +/- 1/8 inch!! (I cannot locate the instruction
manual for my HyGain 4-bay J-Poles, but I am assuming that the
element-to-element spacing is the same (equal), and exact; These
examples are so very much different from what the DB224 units seem to
all be set up as. So: What is correct??? Is there some hidden magic
from the phasing harness and the seemingly inexact element placement
that actually allows a focus of the RF energy where it is needed?
-Or, is this really an important factor??
6. In looking at the pictures and diagrams of the DB228
documentation, I see that the images (as an example) show that the
top-most DB224's four elements are .75 inches
center-line-to-center-line. I see the exact same for the four
elements on the lower DB224. But, the centerline spacing of the
fourth element (lowest one) to the now-upper element of the lower
DB224 is somewhat more than 1.2 inches. (?????) Is this actually
correct? -Or are the pictures and the drawings simply made up by
someone other than an engineer? Here again, I had assumed that the
element spacing "should be" even, and exactly the same!
Thank you in advance for your time and effort!!
73!
-Mike-
K0JTA
