How To Repair Coils
On the MQ-1 and Original Mini-Quad by Mini Products

The Mini Quad used ceramic coil forms that are similar to the MQ-1 plastic forms.
The most common thing to break on the Mini Quad was the spokes. Those can be replaced with a piece of 1/8 inch brazing rod threaded 8-32.
You may have to cut a shallow grove in the old stub and thread it out with a screw driver.
The MQ-1 uses aluminum rod for the spokes, and they are secured with a set screw. Caution: Do NOT over tighten.
The coil forms are a different story. The Mini Quad can be repaired if the ceramic forms are not too teribly ruined.
In either case, as long as the coils themselvs are not destorted you can try the following:

Get a wooden dowel rod that fits snugly in the coil. You don't want to have to force it in, just hand push it.
Cut it about 2 inches long.
Give it a coat of paint or polyurethane to seal it from moisture. You don't want it to swell inside the form.
Wet the dowel and coat the inside of the form (both halves) with Gorilla Glue. Slide the dowel into one half of the broken form.
Apply some Super Glue to one of the broken halves and put the form together. Be sure that the coil is not distorted and that the coils are not on top of eachother.
Hold the form for about 1 or 2 minutes till the super glue sets. Put the coil aside for 24 hrs to allow the
Gorilla Glue to fully cure. Put the antenna back together and put it up. That's It!