Q: Extending Range of Time Capsule WiFi

but seem to have difficulty sending signal thru plaster walls.

Plaster is not the issue here, it is the metal lathe to which the plaster is applied that kills the wireless signals. Basically, you are trying to send wireless through what is in effect, a metal wall. Not much of the wireless signal will make it through the wall...or ceiling.

I am considering running an Ethernet wire out of the TC to the first floor

Good plan. Be sure to use CAT5e or CAT6 Ethernet cabling for the job.

and plugging in a Motorola NVG510 to extend my wireless signal. Is this workable?

Sure, if the Motorola device can be configured to operate as a wireless access point....not as a router. There are no settings or adjustments that will need to made to the TC at all.

You will need to configure the NVG510 to use the exact same wireless network name, exact same wireless security settings and exact same password as the TC network.

For more "how to" details, you really have a question for Motorola support. I'm sure that you know the name of your wireless network and password. The network is using WPA2 Personal security unless you have changed the settings.

Things would be tons easier if you could use a new AirPort Express, since the setup is virtually automatic using AirPort Utility.  Will only take a few minutes to get things going once you have installed and tested the Ethernet cable.

Interior walls are wood lathe with a base and finish coat of plaster laid over it. I am a General Contractor and know my buildings well, and appreciate the tech help regarding my areas lacking a bit in knowledge.

Always nice to work with the guy who does the construction.

Do you think that two inches of plaster (one on either side of the wall) is causing the interfernce?

It doesn't cause interference as that term is used specifically for wireless from other sources.. but metals reflect the signal and solid materials absorb the signal.. the more dense and thicker the material the more signal is absorbed. Wireless at microwave freq travels in dead straight lines.. although the receiver can use reflected signal to help it.. so consider it like a 4" pipe.. from wireless router to client device.. everything in the path of the signal causes issues of some sort.. mostly absorbing signal.. but some glass for instance that is tinted is reflecting it.. the metal content of the glass is enough to prevent signal.. or like a mirror which is of course a flashed thin layer of metal.

Water is the other big one.. add dampness to any material and it will absorb much more signal. As will large water (and meat) bags who get in the way.

Your microwave works at 2.4ghz.. because it is best for heating water. So does wifi at least at the lower band.

So to make sure I understand the physical configuration of my set up, I will connect my Time Capsule to my modem using a CAT5 cable (as it already is), and connect a second CAT5 cable from an ethernet port on my TC to the WAN port of the AirPort Express.

Yes, that is the idea.

The info is here.

http://support.apple.com/kb/HT4145

The article for roaming is referenced in there.. but is this one.

http://support.apple.com/kb/HT4260

What is the difference between CAT5 and CAT5e or CAT6?

Higher speed with higher numbers.. or longer distance at speed.

Cat5 is often actually Cat5e .. which was just a refinement of the standard.. 5 is rated to 100mbit and 5e to gigabit although the distance is not as great.. Cat6 should be used for new installs for longer distance.

If you go to a great deal of work to install network cables it makes sense to use the best.. on the other hand.. Cat5 is likely to do gigabit and speeds are going to take a while to get to 10G. Cable for most people is the least expensive part of the install.. if you install it yourself up to you.

As a note.. the Express only has 100mbit ports anyway.. so it will not matter if you buy an express which cable you use.

If later on you want to upgrade the devices and use gigabit you may not be able to.

That is why cat6 should be used .. but if you test your current cable.. there is a good chance it will do gigabit as long as the distance is say less than 20M of cable.

Looks like LaPastenague has you covered.

If the budget allows, since you appear to be interested in peak performance, I would opt for an AirPort Extreme since it has much faster Gigabity Ethernet ports.

You might want to consider purchasing a newer time capsule vs the older one. I just upgraded from the flat version to the new tower version. No only do i get the latest and greatest specifications, this new time capsule (or airport extreme) provide increased range and speeds in areas where you could not get connectivity before, also apple makes is seamless for you to add another device to your network, either taking over from the old device or providing additional coverage.

I have included a review for you on the new capsule, nearly all the reviews commented on the increase range and preformance.

http://www.macworld.com/article/2044247/review-speedy-networking-makes-apples-ne w-airport-time-capsule-a-good-buy.html

I hope this helps.

Dr. C.