There's no way that your router should affect your transmitting. Most likely both of your rigs are weak into the repeater from that location. I'm a little surprised that the handheld is making it into the repeater if the mobile is noisy, too. A good outside antenna on the roof should cure this, but your house just might be in an area that's shadowed from the repeater. I live on top of a hill, but I couldn't hear a local UHF repeater that was down behind another hill to the north of me. I have a hard time getting into another repeater northwest of here with an HT, too, for the same reason.
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