My Internet connection is via cable with the cable modem entering the house near my office on the top floor. I have and Airport Extreme Base Station about five feet from the cable modem. Three computers are fed from the Base Station via Gigabit Ethernet through a GbEthernet switch. On the wireless side of things, an iMac on the main floor receives the wireless signal just fine. In the basement on the opposite side of the house, a PC laptop has fair to poor reception of the wireless signal. My thought for improving the basement reception is to place an Airport Express unit on the main floor as a relay. Anyone had experience with this kind of setup? My wireless network skills are minimal.

WDS on apple routers can be an incredibly fickle thing, don't rely on it. Especially with airtunes. I've spent hours trying to get stations to connect, sometimes never succeeding. And other times they would just spontaneously disassociate a day, week, or month later.

The express has a much smaller range due to its smaller antenna size also.

Thank you for the assist. To illustrate my level of experience with wireless networks, I had to go to Wikipedia to find out what WDS is. In the article, it mentioned drawbacks that make it very undesirable in my situation.

What if I spent another $179 for an AirPort Extreme base station to be located in either the basement or the main floor. It would not have a cable access to my cable modem. Could it act as a signal booster to enable better reception in the basement of the wireless signal that originates on the top floor?

As Virtual1 says WDS can be pretty fickle, but unless you have a specific need to maintain the MAC (Media Access Control) address of the devices on the network it is unnecessary. You can easily extend a Fi-Fi network without it.

I have a couple of distributed networks using a Time Capsule and multiple Airport Express that has been very reliable and functional. Instead of setting up a WDS my Time Capsule creates the network while the AEs rather than being configured to participate in a WDS network are configured to Extend a wireless network. I also have another AE configured to Join a wireless network that I use to enable a non-network USB printer to work on the network.

This has been a very reliable configuration for me in multiple locations. In fact I can roam throughout the network with my iPad, iPhone, or MacBook Air without ever being aware the connection has been taken over by another base station. In one case I had some spare somewhat elderly Airport Extreme Base stations that I used in place of Airport Express and got even better range in the network.

POST SCRIPT: I just saw your last post and I would be more inclined to spend about the same money on two Airport Express and put one on the ground floor and the other in the basement. The problem in the basement is the two levels of floor the signal goes through will seriously attenuate the signal. Theoretically going to 802.11n and the 5GHz band should give you better signal penetration through the floors, but there are no guarantees. At my son's three story townhouse with concrete floors it took a station on each floor to get a usable signal to the third floor.

Just in case other readers are equally clueless: WDS is "wireless distribution system", although Wikipedia says it could also be Walt Disney Studios.

How do you configure the Airport Express stations? Can you do that wirelessly with Airport Utility running on your Mac after you've plugged them all in at their desired locations or do you do them at your computer and then go plug them in on the other floors?

You plug them in where you want them, and, hopefully, AirPort Utility will find and allow you to configure them.

To amplify Artie505's response with some things I have discovered through personal experience setting up several networks:

1. Always configure the Airport Express, Airport Extreme, or Time Capsule that will be creating the network first and verify you have both LAN (Local Area Network) and WAN (Wide Area Network a.k.a. intgernet) connectivity
2. If the Airport Express(es) being used to extend the network range are within range of the computer you are using to configure the network you should be able to configure them in the intended location but that raises the question of why you need to extend the network
3. If they are not in range, you will obvously have to move them closer to the computer you are using for the configuration but they do not need a physical (ethernet) connection. Wi-Fi works just fine
4. If they are new out of the box they should show up in Airport Utility, but often it will take a minute or two longer to "discover" them so be patient
5. If they are not new out of the box you may have to "reset" them to factory default by inserting a straightened paperclip into the reset next to the audio port on the back of the Airport Express, with the AE plugged in, and hold it for a long six seconds until the light on the front begins to rapidly flash orange.
6. During the setup when you select the option to Extend a network or Join a network you will usually find the network listed on the drop down menu, but if not simply enter the name of the network. All of the other settings with the exception of the Airport Express name and password will be read from the network it is extending or joining.

The only complaint I have about the Airport Express is its lack of dual band (2.4GHz and 5GHz) capability. With the AE it is either/or but not both. I sometimes use an Airport Extreme to extend a network for that very reason. One Airport Extreme is cheaper than two Airport Express and seems to have better range to boot.

The answer to that question must be that 'the intended location' isn't necessarily the location of a client computer or iDevice, but somewhere between the device creating the main network and those client devices. The issue at the edge of reception/range often isn't a complete lack of connectivity but a more variable one, something perhaps even more disruptive.

Thanks for that clarification of my rather simplistic response.

I could use the iMac on the main floor to configure both the base station and the AirPort Express signal booster. The iMac uses the wireless Internet connection whereas my Mac Pro on the top floor uses the GbEthernet. The iMac has a decent connection with both the base station on the top floor and the AirPort Express on the main floor. Is there anything wrong with using the iMac to configure instead of the Mac Pro?

You can use any Mac with the latest version of Airport Utility (5.5.3) installed. It makes no difference. I have often found myself using both my MacBook Air and a Mac at the location during a configuration session.

Thanks to all for the help. I'll give it a try.