Building antennas is my favorite part of the hobby. Mobile HF antennas continue to be the most challenging compromises; a complicated puzzle of mechanical, electrical, aerodynamic, aesthetic, stowability, and simplicity constraints.

My inverted L bugcatcher style antenna has evolved over the past 4 years, providing a lot of fun with regular refinements, tinkering and testing.

The resonating coil is a full 7.5 feet above the base, wound with 14 ga copper, 4-5/8" dia. The shunt matching coil is 18 ga, 2" dia. I make these in my shop using a special winding jig.

I started early on with a vertical mast and traditional type wire capacity hats with perimeter wires to boost efficiency (see my old plan at qsl.net/N1LO). Those hats were great electrically, but were a practical disaster, as they caught a lot more than just bugs! I couldn't make the antenna any taller, so finally, I ended up with a single spoke capacity hat as the only type that wouldn't catch on things. Uh, great Mark.; you just re-invented the inverted EL.

The tail needed a stabilizer to keep it from wagging in the wind. Re-enter the capacity hat. Finally, a practical way to install a hat at the free end of the radiator, where it has the most effect. I revisited the hat scheme, this time leaving off the perimeter wire - no more SKYHOOK! This one is 32" in dia. and has sixteen spokes, made from 0.041" stainless spring wire. The hat has just the right amount of wind drag to stabilize the tail at highway speeds.

The upper section separates quickly, using a thumb clamp, for fast tap point changes. The entire antenna comes apart quickly in 4 ft sections or less without tools, for stowage.

One of the first ones I built caught a giant white dragonfly on the front of the coil, wings and all, perfectly layed out. The dragonfly also catches bugs, so there's the story behind the name.

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Here's a view of the coil and tail assembly:

The mast is 1/2" copper water pipe with a short section of 5/8" fiberglass at the top to accommodate the coil.The tail is 1/4" tubular fiberglass, and may be installed as an L as shown, or straight up, fully vertical, for fixed operation.

Here's a detail of the resonating coil:

The jumper, made from silver plated braid,rotates to any position around the coil. The all-stainless "Piranha Clips" are modified for maximum bite. They make reliable contact even after the coil has weathered. Extra clips short out unused turns to prevent parasitic oscillations.

And finally, here's my custom, "Versa-Brace" mount and shunt matching coil:

Using all triangles, and heavier wall copper at the base, you can grab the base section of the antenna and shake the whole car, but a light guy line is still needed for the drag on the upper section.

© 2011 by M. D. Lowell   Pats. Pending