Yes, an aerial does require a fairly large hole and do it right as there's no going back. Make sure you put your wind shield in the lowest position before you drill...like I DIDN'T. It's almost OK...about 1/4" lower would have been perfect. Also, research antennas that don't need a chrome telescoping pole to work. I assume you're talking about mounting an AM/FM antenna. Earthing (grounding)... I don't know about that. I just took the antenna wire and plugged it into the right spot on the radio. The wire was pretty long and I could have gotten a second plug, cut the wire...but I just coiled it up and tied the coil to a fairing frame support with some plastic tie wraps. I mounted the radio in the left fairing oven (pocket) and installed 4X6 speakers behind the grills that Mother Honda thoughtfully put in the fairing. Installed is too easy a word. I had to Dremel out some plastic, bed the speakers in epoxy paste, and custom make a fiberglass protective cover for the back of the speakers. If you do go to all the work of taking out your dash, consider installing a Gear Position Indicator behind the window where the Neutral, Oil light, etc. are. And as long as everything is torn up, stick a bright red LED block in the small right vent to give you a visual indicator when your radar detector 'lights' off and a Smartire (if you can find one) read-out in the left vent. Since you've knock all of that before lunch, you might want to take the afternoon to install HID bulbs and their ballasts...or, at least, brighter bulbs...oh, and a Stebel Nautilas horn upgrade is easily done...and just to top off a busy day, maybe install a cigarette lighter outlet and a SAE outlet in the right fairing box.
Phew! You'll just have to wait until tomorrow to install the wiring for your RAM ball mounted Garmin Zumo, a charging indicator light, a battery condition gauge, wiring for your fork mounted driving lights, and a Speedo Healer speedometer correcting gadget. Of course, then you need to run all this wiring back to a fuze block mounted on a MCL fuze block plate...and while you're back there, it'd be a good time to wire up the brake light modulator you've been wanting...for safety. And it was the morning and the evening of the second day. Gosh, you've still got Staintune mufflers, a Corbin Smuggler...electrified, of course so you can recharge you bluetooth helmet speaker unit, your iPod, your air mattress blower-up pump, your iPhone...I could go on, but it's late here in California.
Just think of your aerial as a first step down a long road...enjoy...and ride safe!
John