You might check on the cebik.com web site for Moxon rectangle info. My impression is it does NOT have to be 1/2 wave high to be effective for DX. Might be as quick to try it in your location, as your Fresnel Zone, (area within 5 wavelengths of your antenna may affect this more than antenna height depending on your local clutter and earth conductivity. 72, Stuart k5KVH