Q: Need a signal strength meter

folks, you need to understand how 802.11n works. the ipad has a low power 802.11n adapter. it can only use up to mcs rate 7 instead of 15 like your laptops/desktops. this means you will never see more than 150Mbps connection and that would only be if connected to the 5Ghz radio of your access point.

if you see a max of 270 on any device it sounds like your access point doesn't support short guard interval. your ipod connects at 54Mbps because it's only a b/g device. and if your ipad connects at 39Mbps it appears to be using mcs rate 4 and a 20Mhz wide channel. so it sounds like it's connecting to 2.4Ghz radio.

dual band radios depend on the software driver to determine how they will connect to an access point and what band they will prefer if both 2.4 and 5Ghz is available. perhaps the ipad's driver chooses 2.4 first and then 5Ghz only if 2.4 isn't available? if you can disable the 2.4 radio altogether and test the ipad. problem will then be that your ipod won't connect. this is where the newer access points can help if they can run both radios and use separate ssid's for each. that is a way to force your clients to use one radio versus the other.

http://www.ciscostadium.org/en/US/solutions/collateral/ns340/ns394/ns348/ns767/i mages/whitepaper_80211n_design_and_deploymentguidelines-1.jpg

Thanks for the info, jojo. I can't say that I really understand the chart that you referred to, but I do see where certain configurations result in a 39Mbps data rate. However, I do have different SSIDs set on my dual band AirPort, and I get 39Mbps regardless of whether I use 2.4GHz or 5GHz. And, like I said, I get that rate if the iPad is two feet away from the router.

Can anyone explain why the Wifi data rate is so low?

I too saw a max rate of 39 when I had my Airport Extreme (2008 model) set to 802.11n/ b&g. When I changed that to 802.11g only I now see 54. So G is actually faster than N on the iPad.

On another thread someone postulated that this is due to the wifi hardware used and indeed my iPhone has the same limitation.

BTW, after going G-only and doing a restore from iTunes I am now seeing a stable connection and can stream Netflix movies without incident. For a mobile device this is good enough for me. I am, however, upgrading my Airport Extreme so I can have dual bands and allow my other N-capable devices have that access.

I called Apple about the 39Mbps wifi speed limit today. My concern was whether or not my iPad had a hardware problem that should be looked at while under warranty. I was told that this is a known software problem and that they're working on fixing it. That sounds plausible to me. So I plan to enjoy my iPad for now and revisit this problem again in a few months.

Wait a minute. You're getting 39 Mbs on your iPad?!?! Normally I get 1.7Mbps (according to speedtest.net app) and have been thrilled to get 3.5Mbs when resetting all the time! This is my second iPad. I even bought into the who "it's your router" garbage and since I had an old Time capsule, I splurged and got a new Airport Extreme. I was going to try and wait it out but if it's that pathetic, this thing is going back. I need to check the other threads and see what speeds the other folks are getting.

speedtest.net is testing your internet connection. this whole 39Mbps thing is the PHY data rate at which the ipad is showing to be connected at when viewed from the access point's perspective. i hope to get an ipad this week and then i plan to do some testing with other 802.11n access points and a wireless sniffer to check the real data rates.

jojo,

What does that mean "PHY data rate"? What does it say about real world performance? For example, my Mac Mini usually connects at 270 on my network. File transfers between it and my Mac Pro never seem to go faster than about half that.

You could also use the iPhone app called WiFi-Trak, which gives you the signal strength of the WiFi networks it finds.