The capacitor I used was from my junk box and was a 2 to 10pf. The stepper motor was purchased from "Motion King Motor Industry" http://www.motionking.com, and was mailed directly from China. This was the smallest stepper motor I could find with enough torque to turn the capacitor and have enough resolution (1.8 degree) for the very fine tuning this loop requires. The stepper motor controller was bought as a Kit. I purchased it from "Cana Kit", http://www.canakit.com.

I used a LM350 regulator adjusted to turn the loop at a slow speed.
See Figure 3 below:
 

Figure 3

The bird house was made from scrap material I had on hand, and I gave the "house" a coat of paint to match the color of the facade of the complex and coated it with 2 coats of Polyethylene. I purchased the "door and windows" from "Doll House Heaven". http://www.dollhouseheaven.com .

The stepper motor is used to adjust the capacitor for resonance on the frequency that you want to use, you can use your SWR meter to tune for resonance by tuning for a 1.1 swr.

The loop is bi- directional and has good nulls off its sides. I mounted the "house" on 1.5 inch diameter PVC pipe 11 foot in the air. It is supported by a 6 foot tall 2x4, attached to landscape timbers that were in the planting area around my patio. I used Belden 8214 coax to feed the loop, running the coax inside the PVC pipe. I used a 10 conductor shielded cable purchased from Allelectronics for the control of the loop and it too, was run inside of the PVC pipe.

The coax and control cable were buried under the mulch in the planting area and ran into the shack through a board mounted in the bottom of the shack window. I am very satisfied with this antenna.

I have received compliments from my neighbors about the "Bird House" and no one knows it is an antenna. I was quizzed as to what the electrical wires were for and I replied that I am going to install a "weather station" inside in the future. This ruse was to explain any future changes I may make or if repairs are necessary in the future. I could also have said it has a camera inside to observe the Birds!

Figure 4 below, shows the loop and it's associated components. Figure 5 shows the finished project!

You could just mount a vertical coax dipole inside of the PVC pipe instead of making a complicated Antenna, such as a loop. I went with the loop antenna because of the low elevation that I live at and I like building loop antennas. You could purchase a Bird House instead of building one and simply mount it on the PVC.

If anyone wants more particulars on building this loop antenna and controls, feel free to e-mail me at: w0es at hotmail.com

I am now in the process of designing a stealth HF Magnetic loop antenna, using some "Fractal" antenna concepts. If this works out I will share the design with you.  73  W0ES

Editors note: Drawings have been compressed. Contact author if more detail is needed.