Network/connection help...

Long post here.. I hope someone can point me in the right direction as I've got a raging headache now from dealing with this situation and for the health & safety of myself and my computers I'm going to walk away from it for a few hours!

System: 1 iMac, connected with Ethernet to 4th gen Airport Extreme, wifi network for all other devices/computers in the house. Comcast internet. Motorola SB6121 modem. All worked perfectly.

Last evening, husband finished installing an attic antenna. Got the cable from the antenna down the wall into the basement, where it was hooked into the cable routing box that the cable TV had gone into when we had cable TV (we dumped expensive cable TV for broadcast and internet over a year ago). He plugged in the antenna line, hooked it up to a signal amplifier. This required pulling the cable line from that input (we still have Comcast cable internet) and having the cable input now going only to the office, and he put a signal amplifier on that line (a ViewSonics amp/splitter).

TV from antenna works great. Cable modem ceased to work at this point. Comcast website showed an "outage in our area", so we didn't think much of it until this am when the cable internet was still not working.

I called Comcast, they sent a signal to the modem. Nothing. Had me power cycle several times.. nothing. Set up an appt for a tech to come out (days from now). I removed the signal amp, and tried it like that. I was able to get the modem to show all lights 'positive', but no internet. Called Comcast, they were able to send a signal that made the iMac connected to the Airport Extreme via Ethernet come back online. The wifi did not work though. When I power cycled everything to try to bring the wifi back the Ethernet internet to the iMac failed again. I called Comcast back and they sent another signal, I disconnected and reconnected the modem & router.. the Ethernet connection to the iMac is still working, but the wifi will not come back. The light on the Airport Extreme is green, the Airport Utility says it's fine.. but the network diagnostics are no help and can't get the wifi back.

The computers will apparently connect to each other, as I can access the different iTunes libraries wirelessly, but no wifi internet.

I'm writing this on the iMac, too scared to even close safari or reboot computer for fear of losing the ethernet internet on this machine!

Halp.

MQAAord said:

...

Last evening, husband finished installing an attic antenna. Got the cable from the antenna down the wall into the basement, where it was hooked into the cable routing box that the cable TV had gone into when we had cable TV (we dumped expensive cable TV for broadcast and internet over a year ago). He plugged in the antenna line, hooked it up to a signal amplifier. This required pulling the cable line from that input (we still have Comcast cable internet) and having the cable input now going only to the office, and he put a signal amplifier on that line (a ViewSonics amp/splitter).

...

Click to expand...

Based on your post, you have a single cable modem in the house.
Disconnecting the cable line from the input of the modem and goes to what in the office?
If it's not going to another cable modem in the office (one that is compatible with your service), you're not getting internet.

Personally, would not plug an OTA antenna into the modem input designed for their internet/TV service. Have no idea what ramifications that could have, if any - never done it. The OTA needs to be going into an OTA tuner - whether that's your TV or whatever, not your modem. If that OTA is still connected to the modem - disconnect it and plug the cable feed back into it.

So Comcast came out and it turns out the signal amp on the cable line had gone bad (that amp had been installed 8 years ago when we still had cable TV). No need for the amp any more... Removed amp from the line, and he got the internet working hardwired via ethernet.

Wifi would still not come back to life.. but it wasn't the Comcast guy's problem anymore after that, all his job is was to make the cable line work again, which it did.

So I sat & tinkered with settings in the Airport Utility and the Networking wizard... Somehow, and this is TWICE this router (Airport Extreme 4th gen) has done this, has somehow set itself to be a "bridge"!! That's not going to work. Once I made that setting change POOF the wifi magically came back to life.

Wifi back & working. yay me.


Antenna line is fine, TV reception is improved from the bunny ears we had on all the TVs! Dumped cable TV in June of 2011 and haven't looked back since! Kept the cable modem though.