The date bug has nothing to do with operation or connections of the routers, is only to keep a date and log entries. Reason for .50 range is most APs are defaulted to that. Keeps conflicts from happening.
You probably have wireless interferences or not configured correctly.
Links>
Wireless Installation Considerations and
Managing Signal Congestion Ensure the default (dlink) SSID name is changed. Can be anything and not something thats already in use by any neighboring WiFi routers. Under Setup/Wireless/Manual.
What wireless modes are you using?
2.4Ghz Routers only: Try single mode G or N or mixed G and N?
Channel Width set for Auto 20/40Mhz or try 20Mhz only.
Try setting a manual channel to a open or unused channel. 1, 6 or 11. 11 for single mode N if the channel is clear.
What security mode are you using? Preferred security is WPA-Personal. WPA2/AES Only. Some WiFi adapters don't support AES, so you might want to try TPIK only or Auto.
What wireless devices do you have connected?
Any cordless house phones?
Any other WiFi routers in the area? Link> Use
InSSIDer to find out. How many?
Try turning off
Short GI, WLAN Partition,and Extra Wireless Protection if you have it. Under Advanced/Advanced Wireless.
Enable
WMM Enable Under Advanced/Advanced Wireless.