Please help me understand and improve my WiFi performance

Hello everyone - I hope my posting will also help others with the same problem as mine. Please help me. I don't know enough to troubleshoot/ solve my problem on my own and I'd like to learn.


Some info:
Verizon FiOS connection, provisioned for 25Mbps down/ 25Mbps up.
Using a Verizon-branded Westell MI424WR-GEN2 Rev. E with latest firmware avail: 20.19.8. It is connected via Coax.

I have turned-off the radio on the Westell which still acts as a modem and router and use an Apple Aiport Extreme as an access point also with the latest firmware avail (personal preference and because I have a HDD pugged into its USB port).
The AE is positioned in the living room in the middle of the apartment. It is set-up with a 5GHz network for my devices that will work with it and I also have a 2.4GHz network for all the others.Both are encrypted with WPA/WPA2 Personal.

All my devices clients are wireless: an Apple Airport Express, an Apple TV, a Sony PS3, two Android smartphone, one iPhone 4S, an iPad, an Apple MacBook Air and an Acer (Windows 7) laptop, a Brother laser printer, an Epson printer/ scanner.

Frequent tests on speediest.net show I am getting 27-30 Mbps down.
There are times when it will be a mere 1-11 Mbps. I don't know why.
But above all, my problem is that browsing and using the computers on the web doesn't "feel" like I am on a 30 Mbps indeed.

I realize, the computers themselves, the browser etc. everything play a role.

However, I'd like to turn my attention to what I suspect is the major drag.
I live in an apartment building and I am surrounded by wireless "noise" from other APs.

Mac OS 10.8 has this wireless diagnostic tool I used to see what's around me.




I am connected to the SSID with the check-mark on the left. I hid all the info in the first two left columns.

Could you folks please let me know how to read my signal strength to noise ratio? Are my numbers OK? My SSIDs are the first rows and I am sitting 10' away from the AP as I type this. But even then I noticed my signal numbers fluctuate. The Noise never, seems stuck at -92.


I read on the web that my signal number in itself isn't enough enough to evaluate the quality of my wireless network and that it should within -20 to -15 of my noise number. Here we have -40 relative to -92 in the screenshot. As I am typing away, 15 mms later, the signal has become -55 and the noise is still -92.


1) why does my signal number fluctuate?

2) how far apart should the signal number be from the noise number? Anyway to control/ remedy too wide a discrepancy if there is one? Please comment on mine. Is it good?

3) I picked the channels manually, choosing the ones no one else uses. But don't they overlap. Channel 2 on the 2.4GHz network and 36 on the 5GHz. Is that good? I read that the extremities of the range are better/ have wider reach.

4) Where should I pock around in the Westell to pull logs and how do I read them: are data packets being dropped, is there another problem etc.?

5) I use VoIP on my iPhone 4S with the Groundwire app via WiFi and the quality is not consistent. There are days, it will be as good as landline. Others when it is barely useable. Jitter is about 10ms which is bad for a 25Mbps down connection on a 802.11n network (the 5GHz SSID), no?

1) why does my signal number fluctuate?

people walking around, interference from elsewhere, bad karma...

2) how far apart should the signal number be from the noise number?

20 or more is all you need. more is better, 20 is plenty.

Anyway to control/ remedy too wide a discrepancy if there is one?

you have more. more is better. do not try to remedy better.

Please comment on mine. Is it good?

yes

3) I picked the channels manually, choosing the ones no one else uses. But don't they overlap. Channel 2 on the 2.4GHz network and 36 on the 5GHz. Is that good?

choosing unused channels is good. 70% of routers are on channel 6 with the default user name and password.

I read that the extremities of the range are better/ have wider reach.

ignore any further advice from the person who said that.

Thank you for your help. So it sounds like my WiFi set-up is OK.



I did another thing today: I changed the deault 192.168.1.1 DNS server on the Verizon router and the Apple Airport Extreme to opendns's DNS servers 208.67.222.222 and 208.67.220.220.
It did speed thing a little when browsing the web.
I also placed one call over VoIP and the quality was excellent. We will see if it lasts (don't even know if the DNS servers change has any incidence of my VoIP service).

I also have a small wireless router at the office I am not using. I am going to set it up as a repeater to help with the signal strength in the other rooms.

Please let me know if you have other thoughts.