speed test with time capsule half of what it is hard wired

Unless your computer is very close to the Time Capsule, in which case you could expect something in the 85-90% range of the wired connection to the Time Capsule, you are likely losing signal quality due to wireless interference or obstructions.

Wireless bandwidth (speed) decreases with the distance from the main router and any obstructions that may be in the signal path.

If you (or the neighbors) have any cordless phones, they may be interfering with the wireless signal, which can will result in a slower connection in most cases and in some...a loss of signal altogether. Wireless camera/security systems also create problems for wireless networks in this regard.

Any electronic component like a television or amplifier that is close to the router or computer can slow things down.

See this Apple Support Document for more information about Wireless Interference.

http://support.apple.com/kb/HT1365?viewlocale=en_US

Possible cordless phones, security systems, other nearby wireless networks.

Before he luckily moved, I could always tell if my neighbor or his kids...across the street...were talking on his cordless phone because my wireless would slow to half or more. If he was in his front yard, my wireless would drop to a crawl. That's how I discovered, by accident, the problem I was having with my network.

You could try changing the channel on the Time Capsule to see if that helps.