Radio transmits but barely recieves

I think moving could help some but the interference will feed back through the 12 volt system no matter where you locate it.
The cat walk would really expose it to moisture and hot temps so that may not be a wise idea to inclose it there either.

Maybe a 12 volt noise filter on the CB power but i doubt that would get rid of all of it.

 

Yep, I know it's the cause, Inverters plugged in when you shut your truck down will drain your batteries in no time.

 

Remember my post? The most likely issue will be 1> the power cables from the battery will act as an antenna 2> The case of the inverter is most likely plastic since it's a Cobra so the Faraday Style box would have to be placed around it and grounded as well. I have made these boxes out of both Copper plate and Aluminum and of course the Alum. is much cheaper it's just not quite as nice to work with in my mind. But any would work even steel plate but it must not touch the housing of the inverter so you would need to muount the inverter inside with rubber or wood and make sure there is still some ventilation which can be done with wire mesh screen which will still act as a shield.. and then be sure to ground the box to the frame of the truck. the you should most likely shield the supply cable as well and make sure they are grounded as well.. It's never real quick and easy but it's the best chance you have to cut down the noise.. Good Luck