How do I stop my iMac from looking at other networks?

[Shivetya]

There are a few other home networks I can see from my house and apparently my iMac wants to see them as many times waking from sleep it either does not connect to mine or when I search mine is not the top.

My home network (an Apple Airport Extreme) is marked preferred. Can I make it never look for another? How can I remove the others that it has seen?

 

[jab.forburns]

Go to: System Prefrences > Network > WiFi/Airport > Advanced.
From there you can change the order it connects to networks and remove networks it has already connected to.

 

[Shivetya]

They are not in that list. There is only one preferred network and it is mine.

Why this is annoying is that sometimes coming out of sleep it sees my network and connects to it and then suddenly the wireless indication goes blank. When I go to connect it goes out and looks beyond my preferred making me wait till it finally gets around to seeing my network.