I was so close part two..
I very carefully tied a messenger line to the coax cable at the base of the mast . Very carefully I pulled the coax out of the top of the mast .
A huge relief swept over me as I saw the messenger line emerge . I carefully untied the old coax from the messenger line and was getting ready to attach the replacement coax ,when suddenly the messenger line disappeared back into the mast !
Seems my very animated dog saw the spool of line bouncing in the air while I was pulling it through the mast. She grabbed the spool and ran across the yard with it .