[TowerTalk] Radials Questions - 270 or 360 degrees.

[Bill Coleman <aa4lr@arrl.net>]

I am shunt feeding my 15m high tower on 80m. I recently added more 60 
foot ground-mouted radials to go from 13 to 24 total radials. Because 
the tower is situated at the corner of my house, the radial field only 
completes 270 degrees of the circle.

I've been impressed with the improvement in this antenna by doubling 
the radials. The lack of radials in 90 degrees of the circle has me 
wondering if there isn't a way I could improve this further.

Question 1: How does the missing 90 degrees of radials affect the 
pattern of the antenna? The missing segment goes from roughly NW to NE 
-- some important directions from this location.

In thinking about the problem of running radials in this segment, it 
occurs to me that I do have some limited room to sneak a ground wire 
into the basement and run some radials there. This boils down to two 
options:

A) have a 3 foot wire from the tower base enter the basement at the 
floor, then fan out to 3-6  radials varying from 15 to 45 feet. These 
would be either 14 gauge copper wire, or more likely copper foil tape 
(which would stick to the floor and I can walk over it without 
tripping).

B) have a 3 foot wire from the tower base enter the basement at the 
floor, then rise 9 feet vertically to the ceiling, then fan out to 3-6 
radials varying from 15 to 45 feet, run across the ceiling.

Question 2: In looking at option B, is the vertical segment going to 
have an adverse effect on the pattern in the NW to NE direction? Is the 
vertical segment going to change the phase of the currents and 
ultimately destroy any gains by adding the radials?

Question 3: Is there any coupling or danger associated with having 
these radials inside the house? Is there a potential for high voltages 
to appear, or to have the elements radiating RF inside the structure? 
Is this different from option A or B?

Question 4: Of the three options (A, B or do nothing) which offers the 
best possibility of improving the antenna efficiency or evening out the 
radiated pattern of the vertical? What would you recommend and why?


I'd appreciate any suggestions.


Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901

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