extend wireless

Sorry, but Apple designed the "Extend" feature to only work among Apple devices.

If you are trying to "extend" using wireless only, there is almost zero chance that the Time Capsule would be compatible with a Netgear product for this purpose.

You can configure the Time Capsule to provide more wireless coverage by connecting to the Netgear router using a wired Ethernet connection.

I have Netgear N600 DGND3700v2. Set it up as Modem Router Wireless Dual band.

I reset time capsule, opened Airport utility and asked it to extend a wireless network.

Time capsule saw both channels of the network and I was able to join and extend very easily.

Did the same with an airport extreme and two of the airport express devices, and one apple tv.

I believe some modern wireless modems are compatible with the apple chosen format and will be extended

with ease, I know this one was.

I have led you astray above.

I have Joined the netgear network, NOT extended it.

Sorry.