Tram 1411 has the SO-239.
See here for an image of how it is to be mounted. Not sure if Tram included the short mounting pipe to side-mount on a mast.
If not, then you would need to use a mast with an open end, and pass the coax down through that. If you are mounting to a chimney mount, tripod mount, eave mount or wall mount, this shouldn't be a problem.
https://www.radioresearch.us/Antenna-Broad-Band-Discone-Scanner-Base-25-1300-p/1411.htm If it didn't come with the short mast and side clamp, you can improvise with a short piece of EMT or PVC and a antenna mast clamp. The antenna does not have to be electrically connected to the mast, so either way it should work fine.
That said, I would use EMT or similar metal pipe so you can ground the whole mast and ground plane radials.