I only know of stream sites and you have to sign up for a monthly fee. How long have you had a bad signal for your TNT channel? Is it just recent? Did you try the usual troubleshooting methods such as unplugging or switching off receiver, doing a rescan, etc?
I don't think rain should screw up your signal though. The dish is robust, it would take lightning to strike the dish in order to affect the signal strength.
