If you read W8JI's page, you'll see that a rhombic is not all it's cracked up to be. (In English, this means that you are wasting your time and money if you install one.)
There are some pretty tall tales about rhombics. Here's one. Take it with a large grain of salt.
I'm sorry, but a rhombic is just not that good, even if you DO have one pointed at every direction of the compass as W6AM did.
"The W6AM station was legendary around the world. Don could beat you in a pileup for some obscure African station no matter what band, and even if you were on the east coast. And him in Southern California.
"Don was #1 on ARRL's DXCC Honor Roll, and you didn't argue. No matter where you were, no matter what you were running, Don had beaten you in a pileup. More than once."