Signal strength application for Wireless EVDO USB MC727 modem

[siam]

Ive just started using a Novatel Wireless EVDO MC727 Rev A USB wireless modem on my iMac , due to the fact I live in a low signal area I am trying to tweak my external roof antenna that I connect to the MC727 I have seen on some Windows XP computers using the same MC727 a small on screen signal strength meter showing the signal strength being received , and its shown in a signal bar format, so the better the signal the larger and higher the signal bars show up on the signal strength meter , but un fortunately ive not been able to find such a signal strength bar meter to use on my iMac, as I live in Thailand the wireless carrier who runs the CDMA network do not supply any Mac software which has such an on screen signal meter, so I am wondering if any one may know of such a signal meter application I could install on my iMac that would show some sort of signal strength meter, this would then allow me to fine tune my external antenna .