I had some trouble figuring it out at first...
These are the two BNC connectors, Ignore the text.
![](http://www.upscale.utoronto.ca/GeneralInterest/Harrison/Oscilloscope/Images/bnc.gif)
This is an SO-239 connector- I have this on my J-pole
![](http://www.orbito.com/images/Connectors/so239.jpg)
The SO-239 connects to the PL-259
![](http://www.hsp.it/radio/offerte/PL-259.jpg)
See what you have and what you need, or tell us what you have and we'll tell you what you need.
It sounds like you need a BNC Male to SO-239 adapter... Not sure tho.