Q: Time Capsule & Airport Express Keeps Disconnecting

Let's start by looking at the location of the AirPort Express in relation to the TC. Is it in the same room, different room, or different floor? If different room or floor, what it the basic building construction material used in the walls/ceilings in your home?

What exact models are each of your base stations?

Please start over again and perform a Hard Reset on the AirPort Express.

Move the Express to the same room as the Time Capsule and set up the Express again to extend the network.

Leave the Express in the same room for an hour or two to make sure that the connection will remain stable.

Assuming that the connection remains stable, move the Express to a point that is about half way between the Time Capsule and general area that needs more wireless coverage.

Power up the Express and check the network.

The more that you have a line-of-sight relationship between the Time Capsule and AirPort Express, the better and more reliably the network will perform.

Unfortunately, when you "extend a wireless network" this way.....even if you have line-of-sight between the Time Capsule and AirPort Express.....you will lose about half of the potential speed on the entire network.  Any obstructions like walls, ceilings, furniture, etc in the signal path between the Time Capsule and AirPort Express will slow the signal even more.

Your network will perform much better and much more reliably if you can consider connecting the AirPort Express back to the Time Capsule using a permanent, wired Ethernet cable connection. This way, you can locate the AirPort Express at the exact location where you need more wireless coverage and there will be no loss in the Ethernet cable connection back to the Time Capsule......assuming that the Ethernet cable will not be any longer than about 325 feet, or about 100 meters.

Ok, the concrete walls will pose a problem.

To better understand extending a Wi-Fi network using a wireless connection, the placement of the extending base station is critical. In this case the AirPort Express, can only extend the network it receives. What this means is that you may get a strong "5 bar" signal at the location of the Express, but the bandwidth (max. speed potential) of that connection will potentially be useless.

... and that is because the Express can only extend the Wi-Fi network at the same bandwidth that it receives it.

Check out the linked AirPort User tip for details on optimal placement. Please report back your results.

If I will keep both TC and AE in same room then I don't think it would benefit me, the main reason I bought the AE to make it work as a signal booster!

Sorry, but it appears that you did not read my instructions carefully.  Please check above to verify that I advised that you should.....

1) Set up the AirPort Extreme in the same room as the Time Capsule

2) Make sure things are working

3) Then....move the Express to a point that is about half way between the Time Capsule and the general area where you need more wireless coverage  (This appears to be the step that you missed).

I did not advise you to leave the AirPort Express in the same room as the Time Capsule permanently.....I only asked you to set up the AirPort Express in the same room as the Time Capsule (to insure a correct setup).

Also to connect both of them with an ethernet cable is not the ideal solution for me as I don't want to run the cable across the apartment.

Then, the next best option would be to use a pair of Ethernet over Powerline (EoP) adapters to send an Ethernet signal over the existing AC powerlines in your home.  The theory with these devices is that you already have the wiring in place.....you just need the adapters.

Any computer/electronics superstore will have a selection of EoP adapters on hand. Ask the folks at the store which brand that they would recommend for your home.

This would almost always be a much better solution than trying to use only wireless to get the AirPort Express to connect to the Time Capsule, especially if the wireless signal must pass through a concrete wall before it will reach the AirPort Express.

If you try to use wireless to connect the Express and Time Capsule.....As Tesserax notes...not much of the signal from the Time Capsule will ever get through the cement wall.  So, the Express will receive a very poor signal to extend. It can only extend the quality of signal that it receives.  There will be little to no benefit gained on your network.

The Airport Utility shows me both the TC and AE disconnecting and a yellow triangle appears next to each of them and when I click on them it asks me to click on "Forget"!, but if I keep it for a second it will reconnect and then of course disconnect again and again..

Ah, when it rains, it pours...

That is another issue that has popped up recently affecting a number of users.

Do you happen to have Back to My Mac configured on any of your base stations? If so, disable it, and this issue should disappear. We will have to wait for Apple to actually fix the problem.

OK, thanks for the clarification.  Obviously, if you cannot get the Express to connect to the Time Capsule correctly when the Express is close to the Time Capsule.....then the Express will never work correctly when it is located further away from the Time Capsule.

And, obviously if the Time Capsule is not working correctly at this time, then neither will the AirPort Express. So, you will need to backtrack and do some checks.

We can try to get the Express working by connecting using wireless to the Time Capsule when the Express is close to the Time Capsule, but I'm afraid that even if we can do this, the cement walls are going to kill the wireless signal and the Express will not function correctly when you move it away from the room where the Time Capsule is located.

If you want to proceed, then I would like you to power off the AirPort Express and leave it off for now, and then make sure that the Time Capsule is operating correctly. In other words, when you open AirPort Utility to check the Time Capsule, you will see the Time Capsule and it will display a green light.....like the example below.

Check the Time Capsule using AirPort Utility a few times over the next 30-60 minutes and report back on your results. We cannot proceed with trying to extend the network until the Time Capsule is operating correctly.

Just to be sure, which method did you use from the tip?

Also, it is critical that the Express if off and that you are just measuring SNR for the TC at the location where you had placed the Express.

Easy-peasy.

Just use the AirPort Utility, as follows to disable it:

• Run the AirPort Utility; select the TC, and then, select Edit.
• On the Base Station tab, go to the Back to My Mac section at the bottom of the window.
• Select your Apple ID, and then, select the minus "-" button to delete it. Delete all Apple IDs listed.
• Click on Update and allow the base station to restart.
• Do this for each base station that you may have set up BtMM.