After much thought, here's what I came up with:
A homemade ground plane using 4' Firestiks.
Materials:
A. One Simpson Strong Tie (6" x 12"). These are available at any Lowe's or Home Depot.
B. Two hose clamps (For attaching antenna bracket to mast)
C. Three 4’ fiberglass mobile antennas (any brand)
D. One PL259 stud mount (I used a Firestik KV-4A)
E. Two lug stud mounts (I used a Firestik KV-4)
F. One PL259 right angle coax connector (male to female).
Instructions:
1. Drill a ½” hole in the center of the 12” length of the strong tie.
2. Make a 90 degree bend so that the 6” length is pointed down (this is what attaches to the mast.)
3. Using a vice, make two bends in the 12” length 3 ½” from each end, leaving 5” across the top. Bend each downward and inward so that the two form a 90 degree angle. This will insure that the radials will be pointing outward at 45 degrees insuring an impendence of about 50 ohms.
4. Install the PL259 stud mount in the top center hole. This will hold your vertical element. Be sure and use a plastic sleeve with the top portion so the antenna does not contact the metal bracket. Do not use a sleeve between the coaxial connector and the bracket. This will insure the coax’s shield is grounded to the bracket.
5. Attach the Right Angle Coax Connector.
6. Holes for the radials come pre-drilled on the strong tie. Simply install lug studs in them. Be sure and use only one plastic sleeve (or none) on each so the antennas will be in direct contact with the metal bracket.
7. I chose to add a self-tapping screw in one of the small pre-drilled holes to attach a ground wire to which will run to a ground rod.
All that's left is to screw in the antennas!
I haven't put it in the air yet as I am waiting on my coax and SWR meter. But I did set it on my patio and hook my 35-year-old Royce CB to it using a 3' jumper. I was immediately greeted by what I thought was a loud local but turned out being someone in Oregon. (I'm in Texas). I didn't try and talk as I can't check my SWR.
In the meantime, I might change out the vertical Firestik for a Wilson 1000 (leaving the two remaining Firestiks as radials) as originally planned. Or maybe a Wilson Trucker 2000. Or a Sirio 5000. Or Predator. Or the old standby, a 102" steel whip. The possibilities are endless.
Will an antenna of this design work? I think so.
1. For the most part, even though mobile CB antennas are often rated 5/8 wave or longer, I'm told they basically “act” as ¼ wave antennas regardless of their length or the amount of wire used. So it stands to reason they can be substituted for full ¼ wave (102”) elements and radials.
2. Antennas with only one radial are largely directional (stronger in the direction the radial is pointed.) And while 3 or 4 (or more) radials are recommended for a fully Omni-directional antenna, some say 2 radials are nearly as effective and produce more of an Omni-directional pattern than the 180 degree pattern that might be expected.
Final Thoughts:
I’m guessing the first question will be, “Why spend so much money on a homemade antenna and not just buy an A99 instead? Answer: You’re right. I have about $80 invested in this thing (not counting the mast, coax, etc.) But I greatly enjoyed the time spent researching, designing, and putting it all together. And I’ll take great pleasure in using it.
And of course, someone will point out, “You don’t really have a base station antenna. It’s still just a mobile antenna.” Right you are. But I agree with what MSGED2007 said earlier. It's performance will likely be the equivalent of mounting a Firestik in the center of the roof of my car and then hoisting the vehicle 15’ in the air. And I’m good with that.
The items I'm waiting on should be here in a day or two but as luck would have it, the weather now has gone to pot--Freezing rain and COLD! And according to the forecast, temps won't even reach the 40s for a week or so. Will probably be a while before I can report back.
Over and out.
