Is there a "cure" for ingition noise overpowering a CB radio?

[Pat Martone]

For group touring purposes, I have installed a CB radio in my Model A.

While it works great when the engine is not running, the ignition noise (from spark plugs or coil?) makes the CB radio unusable.

I do not think I am experiencing alternator ("whining") noise; I am convinced it is spark noise.

I have tried power line filters without success; it appears the ignition noise is entering the radio through the antenna connection on back of the radio itself, since when I disconnect the antenna, some of the ignition noise is attenuated.

Has anyone else experienced and resolved this problem?

Thank you.