1st generation time capsule painfully slow

Question

I've been dealing with this issue for some time now.  I've searched all over the internet for a solution, and I've yet to find anything that works.  I'm hoping a Time Capsule expert may be able to help me sort this problem out.
I have a 1st generation, 1tb Time Capsule.  I've had one since they first were released.  Use already had one fail from the dreaded dead power supply issue that was affecting many 1st gens after reaching 18 months old.  This one is less than a year old.
I have Verizon Fios with a blazingly fast Internet connection.  When I plug directly in to my ISP's router via Ethernet, my connection is amazing.  I realize that wifi connections are much slower than Ethernet, but what I've been dealing with lately is ridiculous.
I believe the problem lies with the Time Capsule.  It's set to 801.11n, 5ghz only, maximum throughput (24mbps), WPA2 personal security, latest firmware.  Wifi connections via the TC are great at first, but they seem to degrade as time goes by until I finally have to reboot the TC, then the speeds are back up to normal again for a while.
The problems also seem to arise whenever a computer is backing up to the TC.  I understand that speeds might slow down while a backup is occurring, but I would expect that they would return to normal when the backup is complete.  Unfortunately, the speeds often slow down so much that the backup never actually finishes, and often it comes up with an error saying that the disk is no longer available.
Trying to share a file between my macs is often impossible.  Even a small file, say 5mb, can take minutes to transfer between to wifi-connected devices.  Sometimes a TC reboot with fix this, other times it won't.
My setup is like this - Verizon router with wifi disabled, serving as the DHCP router for my entire internal network, connected via Ethernet to my Time Capsule and an Airport Express.  The Time Capsule is set up in bridge mode and serves as the 802.11n wifi source for my newer wifi devices.  The Airport Express is also set up in bridge mode and serves as the 802.11b/g wifi source for my older wifi devices.
Due to the nature of the Fios service, I can't have the Time Capsule set up as the DHCP distributer for the network.  However, even when I didn't have Fios and the Time Capsule was set up as the dhcp distributor, I suffered from these slow connection issues.
Are the 1st generation TCs plagues with issues?  Is it just time for me to get a new one?
Any help or insight would be greatly appreciated.

Answer 1

Unfortunately, you are experiencing one of the downsides to 5 GHz. That's because the higher frequency 5 GHz signals are much weaker than 2.4 GHz signals.
After all, you always have to give up something to gain something else. In the case of 5 GHz, you gain potential speed but in return, you must give up penetration power and distance capability.
In order to work well, 5 GHz signals need to almost have a line-of-sight relationship between devices. Unless you can achieve this, you will do much better to leave the Time Capsule running at the 802.11n (b/g compatible) 2.4 GHz Radio Mode and allow the Express devices to "extend" that network.
As for the location of the AirPort Express devices in an exended network, that is critical for best performance. That's because the Express can only "extend" the quality and bandwidth of the signal that it receives. Post back if you need a few more tips on how to find the best location for the AirPort Express devices.
Would the new airport extreme fix the problem?
Unfortunately, no.