On 9/5/2017 5:11 PM, Rudy Bakalov via TowerTalk wrote:
Now that I have decided to lay on the ground radials,
How many do you plan to install? You'll need a lot more on the ground
than elevated to achieve the same low ground loss. 4 per vertical is
minimum for elevated radials, and I wouldn't consider anything less than
32 on-ground radials. Elevated radials need to be close to a quarter
wave, but on-ground radials are lengthened by their proximity to the
earth, so have VF on the order of 0.8. In other words, they can be 20%
shorter.
another practical question pops up and so far I have not found an answer.
I plan on shunt feeding for 160 the tower in the center of my 80 4SQ,
How tall is the tower? Depending on its height, it might be worth
rigging a sloping wire from the top and feeding it from the base against
radials. I'd try an NEC model. I'm doing that and getting a couple of dB
from the tower acting as a passive reflector. (And it needs radials too!)
can I/should I tie all the radials together? The 160 radials will certainly
cover the same distance as the 80 radials so is there a requirement for each 80
element to have its own radials?
I don't know enough to offer advice on this.
73, Jim K9YC
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