My aluminum groundplane seems to have a problem in the loading coil. I'm guessing a loose solder joint. The problem is that it is surrounded by a plastic tube. Has anyone ever had to get into one ? If so how did you salvage it after cutting into the enclosure ? My antenna is an A/S ASPB-350 . It has a loading coil similar to the A/S Super Magnum-
Take the antenna of of its mounting pole /pipe. Take the mounting bracket off from the coil/element. There are two u bolts and possibly two bolts that hold the two halves of the mounting bracket together. The nut on the so 239 connector also should be removed be careful not to strip it. after you have taken these steps , you can slide the insulator and plastic cover upward to expose the coil inside some of these have glue on the inside. The other method is to break the plastic tube out a piece at a time.
After you repair the connection tape with scotch 88 tape and seal with scotchkote electrical coating. The common failure point is either where the tap on the coil is soldered to a roll pin . Or at the bottom od the coil at grounded end press fit in to the base assy.
Have repaired a many M-117/ASPB 350
If the connection to the so239 is the problem just mount your new one external at the base.
POST SOME PICS so others can see the results.
73 RCB