This URL from the archive files on vanagon.com tells the procedure:
ftp://gerry.vanagon.com/pub/technical/how-to/vanagon-antenna-removal.txt

Mark B. Magee wrote:

> Volks,
> Mast broken very low on radio antenna, Bentley is silent on radio
> removal/radio antenna replacement. Could anyone give me the ABC's of
> installing a new radio antenna. I understand that the driver side
> headlight mounting bracket has to come out, where I having trouble is
> getting the antenna plugged into the back of the radio.
> All assistance appreciated.
>
> --
> ><>     ><>     ><>     ><>     ><>     ><>     ><>     ><>     ><>
> Shalom
> Mark B. Magee
> 87GL
> 91 Westy
> 96 Suzuki 4WD Sport
> Kemah TX USA
> John 14:6