"rubber"antenna for my jr
I have been using the Smiley Rubber duckey antena with no issues what'so ever on my Multiplex 4000.
It is said that you will loose a small percentage of range but taken into consideration, that your normal range is out of sight in most application, it should not be a problem.
I have tested mine on a test plane flew it to a dot in the sky.
I now only use this antena.