Iphone 3g having wifi problems - app problem?

Question

Hi,
I just got given a iphone 3g as a hand me down, and I think im having problems with the wifi, but cant find anything sensible as fix (one video suggested put it in the oven)
when using safari, or internet apps (namely, facebook, kik, igotchat) and probably any other apps that need an internet connection, I get randomly "disconnected" for lack of a better word. on safari it says "no network is available, please connect to wifi" and kik says the same thing.  normally with safari i can just refresh the page a couple of times, and it will work, but when using the instant messenger apps, it just doesnt send or receive my messages, for hours,
the thing is, when all this is going on, i dont actully lose wifi, the signal symbol is there the whole time, I go into settings and my routers name is there, and also igotchat's wifi status always says its good.
So far ive tried changing my wireless channel on the router, and also trying to use it on a diferent internet connection, but the problem still persists (my home network is fine on all other devices)
i understand that im using "legacy" apps, and therefore not on the latest version, but im on the latest that ios 4.2.1 will allow, and im sure app developers/apple wouldnt just have people unable to use their old devices
so what im asking is there any fixes i can try, either with the phone, the router, or the apps, as currently its fairly unusable as an internet device
im pretty new to apple products (except my old ipod video) but im decent with technology so il try anything if it might help even slightly

Answer 1

Hello monolith,
So, you are still having the disconnection after changing the protocol to G only.  Another tip some folks have used to help clear this up, is to set up a Static address for your phone.  This is something I do at work, so I took the practice home. 
Not all routers, will let you reserve addresses for devices, but some do.  If your router is the DHCP for your network, look in the network settings for resevations.
If you can add a reservation, then add the one your phone is already using to see if this elimates the problem, at least on your network.
If you know how to set up a reservation, you can skip this part.
First write down the network settings that are on your phone under the blue > dot.  When you change from DHCP to Static, iOS will clear the settings, so write them down.
Tap on Static and fill in the information you just wrote down for the static address settings.
Now put the phone in airplane mode or turn off WiFi on your phone.
Assuming you can add a reservation to your router, you will need to know you phone's MAC address (Settings>About WiFi address) so you can find it in the address pool. 
Your phone's address in the pool should be the same as what you wrote down already and revoke the address from the pool.
Now you can make the new reservation and type in the IP address, the MAC address and a description of your phone, typically.
Save the settings and the router will probably restart the network, so make sure anything already on the network is ready to go offline for a minute or so.
Take your phone off airplane mode and it should join the network.  If it doesn't, confirm the addresses are the same and make sure the MAC address is correct.
If your router can't take a reservation, then the only other suggestion I can make is to aquire an Apple router.  Check around ebay to see if you can't get an old AirPort Extreme Base Station (the ones that look like a space ship) and attach it to your nettwork as a subnet.  I just spotted some on ebay for under $10.  Also if your network is secure, just make sure the subnet is also secure. 
If you're unfamilar with Apple routers, you set them up using software from Apple, so if you have a Windows PC you will need to download the AirPort Utility software http://support.apple.com/kb/DL524 and install it on your PC.
Beyond that I'm afraid I can't help, sorry.
Best of luck,
UG