Most of the antennas I have also favor 2 directions.  Unfortunately 
those directions are up and down.

73, Steve KW3A

On 10/11/2014 9:13 AM, Mike Duke, K5XU wrote:
> Yes, I think it's a minimum of 1 wave length per leg, but multiple wave
> lengths mean more gain.
>
> Most people would optimize their rhombic for a given band, say 20 or 15
> meters, and then use it on any of the other bands where they could get
> it to tune.
>
> On the main band, the strongest gain is in two directions. I remember
> hearing W7LUN say that his favored Indianapolis, and Melbourne,
> Australia on 15 meters.
>
> There is also a terminated rhombic, which has a resistance at the end
> opposite the feed point. That changes both the gain and the
> directivity, but I don't know exactly in what ways.
>
> The legendary Don Wallace, the original holder of W6AM, had 100 foot
> tall utility type wooden poles that held multiple rhombics, each
> favoring different directions.
>
> His family made a mint worth of money when that system was dismantled
> and the property sold to developers.
>