I've seen a few new Coax to Ethernet adapters trickling onto the market.  They claim speeds of up to 270 Mb/s. 

If you are wondering how coax fits into our discussion of bandwidth above, it is a shared medium - very similar to your electrical wiring.  However, unlike your electrical wiring, Coax IS designed to carry data like this, and is very good at it.  There would be very little noise on the Coax in the frequencies the data is using (unless your cable company is doing something strange.)

I expect these adapters to perform well, but at their current price I won't be implementing them anytime soon in my house.

http://www.netgear.com/Products/PowerlineNetworking/Coax/MCAB1001.aspx

thorin wrote on May 4^th, 2009 at 9:25pm:

Yes, you are correct.  In fact, a UPS would have a much bigger effect, especially a higher end UPS, which cleans all the noise out of the electrical signal.  Along with the noise, it is likely to eliminate your network traffic right out.  I have heard of people successfully running powerline adapters off an electrical strip, and a lower end UPS should be no different, but it is not the "recommended" setup.

thorin wrote on May 4^th, 2009 at 9:25pm:

If you can wire the rooms, that is going to be the best option.  There are lots of reasons to do it, and the connection is magnitudes better than any alternative in many ways.  Even the cost is often comparable to most of the alternatives, although wireless is starting to get pretty cheap.

WARNING:::::: i have a lot of questions...... on this subject...... (please help).......

[color=#ff000[size=11]0]Have a Sony Vaio (XP) with Intel Wirelss PRO ........ can get service from house .... person with service is UNKNOWN and dont know the distance .... and is on the 802.11g and another is 802.11b (signal is at 1 bar, which is low, but can get it)
BUT.....................
Have a Dell with a wireless (1397 802.11g mini half card)....... can NOT get signal to connect with this (states that signal is TOO weak, eventhough it has 1 bar TOO)........ again, dont know the person and/or how far the signal is comming from...[/size][/color]

NOW, i have an adapter (802.11N) which ONLY works on the DELL, but NOT on the SONY.
WHY does it do that?

Another question: i have been told about a "repeater"/signal expander??? and that this could be of better value.....
Then i have been told that FIRST I have to know they type of ROUTER that the other person has and use the same type and/or configure it..... true/not????

Also, what is the difference btwn 802.11 - G and N???

Would it be wise to stick with the adapter (N) or to get a "repeater" (and would I have to know all that information first before I set it up).
I would like something that has mobility and convience.... Do I have the right one?

(Sorry, one more question......=====  Is it true that if i got a "G" it would work on any, such as b,g,a,etc BUT since I have a "N" it will only work with g's or b's)

I am truely baffled with this. I just thought that once I purchased the DELL , it would work like the SONY wireless card........ easy......... guess not....... please give me some suggestions.... thank you sooooooooooooooo much....

For anyone who might be looking in on this old thread, here's a recent article extolling some of the virtues of powerline adapters:

The secret sauce: powerline network adapters