My stubby antenna just came in today. I also noticed the open "well" at the base of the antenna mount. To help remedy this look, I used my OEM antenna boot by clipping only the amount off the top/tip in order to fit snugly at the base and then tucked in the bottom of the boot to the chrome holder so it gives a more OEM fit to it.
I also checked the signal using it and I didnt notice any difference either. But I was in town too. I usually listen to XM radio anyway.
But I must say that I do like the appearance overall on how it compliments the H2 on the vehicle. Well worth the $.