Just because the light is on, doesn't mean anybody's at home!
I know from experience that the wireless light can be on when there is absolutely NO signal from a HH3 and even if there IS a signal, it does not mean that the HH3 will definitely allocate an IP address and start the throughput of data.
From my experience with HH3s, what you are describing is typical of one that is going sour.
I suggest that you first try a Factory Reset by going into the Advanced settings on the HH to see if that will restore sanity. Note that this will remove any settings you may have applied and will restore WPA encryption which is fine with all Apple products.
Next, delete all previous wireless settings from the Network pane of System Preferences on your Mac. Now try connecting with the default username and password as noted on the label on the rear of the HH and see what happens.
If that does not cure the problem, call 0800 111 4567, be polite but firm and insist on receiving a replacement hub . . . or go with my original suggestion and get an Airport Extreme. You will not regret it if you do!
the home hub 3 seem to be prone to wifi problems since a recent firmware update in june
i had the EXACT same problems
i myself rang for a new home hub and when i fitted it it was exactly the same , rubbish at wifi.
the onlyway i could solve it is to do the decent thing and THROW the home hub 3 in the bin and buy a new cable router
i fitted a netgear n750 and its the buisness, wifi is once again wicked instantly
my advice is bin the home hub 3 and do the same mate, its the firmware
I've just had the infinity install today, but as the HH3 arrived a few days ago, I started using it on my ADSL line. I have a similar problem, it seems that all of my N capable devices get disconnected at the same time, although the older b/g devices can still work fine when this happens. The connection from the laptop gets stuck at 'Attempting to authenticate', makes no difference if I set the hub to just b/g, it still dumps all the N capable devices at the same time - only a reboot of the hub resolves the issue. Always seems to be caused by another device being turned on/activated, be it a smart phone/kindle/laptop whatever.
Does seem that the HH3 is a pile of c**p, time to go buy something decent! .
I had an issue with a PC randomly dropping the wireless connection and at first thought it was caused by Smart scanning - it wasn't, I also disabled 'N' compatibility, but that didn't help either.
What did cure it was changing the Country Region of the Wireless Card\Adapter on the PC from IC (1-11) to MKK1 (1-14) in the card's properties\advanced tab in Control Panel>Device Manager>Network Adapter ...in the 24hrs since there have been no drop-outs at all.
See the image below:
Hope this helps.
Interesting one, that.
But . . . I have seen quite a few wifi problems with Macs, where replacing the HH3 (or an HH2 as the case may be) with a new one cured the problem instantly unless the new router was bad as well! The Mac does not have any router settings that need tinkering with.
In my experience with many machines, the Mac's built-in WiFi very rarely has trouble with any routers other than bad examples of HH2 and HH3.