KC8AON's QRP PROJECTS

SPIKE GROUNDMOUNT FOR ANTENNAS WITH 3/8" X 24 THREAD BASE

AN EASY TO DEPLOY ANTENNA MOUNT FOR FIELD OPERATION

I USE THIS MOUNT WITH MY MP-1 ANTENNA

Here's a neat little contraption I built after the little tripod mount that came with my MP-1 antenna kept blowing over in the field. It's a simple "spike" mount that the antenna screws into, and then sticks in the ground to support the antenna in the field. The tripod is still handy when operating with the antenna indoors, but the spike is much quicker in the field and holds the antenna up even in moderate wind.

As you can see in the diagram above, the spike mount is fairly simple to build. All I did was take a piece of 1.5" x 1/8" flat steel stock that is about 5" long and bent it into an "L" shape by clamping it in a bench vise and bending it 90 degrees. I then drilled a 1/2" hole in the end used for the top to mount a 3/8" x 24 thread to SO-239 antenna adapter in for the antenna and coax to connect to. Then I drilled a smaller hole in the other side and attached a brass 6-32 bolt with a knurled nut to attach the ground radials to. The brass bolts and knurled nuts can be found at places like Lowes and Home Depot. The spike is welded to this same section of the L bracket, and it is made from some 5/16" steel rod. I used an old trunk lid spring from a car (I work in a Honda dealership), but you can use plain steel rod available from hardware stores.

To use the mount, screw the antenna into the 3/8" socket, and the coax into the SO-239 and then shove the spike into the ground while keeping the antenna as vertical as possible. Attach the ground radials to the brass bolt and spread them out on the ground like spokes in a wheel and then tune the antenna to frequency. I use this mount with my MP-1 portable antenna, but there is no reason that it couldn't be used with other antennas that have the 3/8" x 24 thread base such as the Hamstick type mobile antennas and the Hustler coil loaded mobile antennas making them double as field antennas.

73