I'm still trying to get a grip on how wireless signals travel from a wireless router. Many in this forum have helped me to understand. And I appreciate that. But I am struggling with a problem of inconsistent and unstable wireless performance in what I think is a challenging wireless environment.
The environment is a five story town house, with an open atrium and a semi-circular staircase that goes from floor to floor from the first to the fifth. It is an old building contructed circa 1890.
On each floor there are three spaces, front (facing the street), middle, and rear. On the first floor the front and middle are the entrance and foyer. The rear is the kitchen On the second floor front to rear are the living room, 2nd floor landing, and dining room. On the third floor there is the library, floor landing and bedroom. On the fourth floor there is a bedroom, the floor landing, and another bedroom. Finally, on the fifth floor there is a bedroom, an office, and a TV watching room/den.
The cable-modem is on the fifth floor rear. In the same room is a Belkin Pre-N wireless router. The router is tethered to the cable-modem by a length of ethernet cable. Another length of ethernet cable connects an available port on the router to a Siemens SpeedStream Model2521 Powerline Ethernet adapter that is plugged into an electrical outlet. In the middle office there is a MAC iBook equipped with a built-in Airport wireless adapter. In the front bedroom there is a MAC Powerbook also with a built-in Airport wireless adapter.
On the fourth floor rear bedroom there is a Toshiba notebook computer with a built-in wireless adapter.
On the third floor there is a Thinkpad A22p with a Belkin Pre-N PC card wireless network adapter.
There are no computers on the second floor.
On the first floor rear, in the kitchen, there is a Thinkpad T21 with a Belkin Pre-N PC card wireless network adapter. 8 feet away plugged into an electrical outlet is a Siemens SpeedStream Powerline Wireless Access Point.
Strangely, the wireless signal from the fifth floor rear room where the router is, to the adjoining office, is inconsistent and unstable when using the iBook.
The signal to the Toshiba in the fourth floor rear bedroom is usually around 80%. Fine.
The signal to the Thinkpad A22p in the front third floor library is very good to excellent, about 87%.
But the signal to the Thinkpad T21 in the rear kitchen area is inconsistent and unstable. Yesterday, for example the signal strength was excellent for a few minutes and then it disappeared altogether. I clicked on SCAN in the Belkin Wireless Client Utility and got a result that said, "No Scan Results." Couldn't figure it out. I uninstalled and re-installed the Belkin Pre-N card and the wireless client utility and what do you know, I get excellent signal strength to my network. An hour and a half later, no signal at all.
I'm thinking that vertically-oriented five story spaces are especially challenging, more so than a horizontally-oriented space.
No one in the house was using a 2.4GHz cordless phone or a microwave oven when the signal dropped. Could it be that someone in the adjoining home (separated by a common brick wall), could have caused my signal to drop by using a 2.4GHz cordless phone or microwave oven.
I also found once that when there was a signal drop the computer somehow got off my network and connected to another in the area with a weaker signal strength. How/why does that happen. How can I keep the computers in this house on my own network.
I'm thinking about moving the cable-modem and router down to the third floor where it will be equadistant to the first and fifth floors. Is that likely to help?
Sorry for the long post, but maybe it and the responses to it (if any) will be instructive to others.