I got frustrated at not having a good way to string a wire antenna at the house and really wanted something portable for setting up an EMCOM station.  I happened to have a hamstick MFJ-1640T.
After reading what others have said, I picked up another MFJ-1640T ($14.95)
and the dipole adapter MFJ-347 Double T Pipe Mount W/SO-239 $19.95
Total cost of the antenna system is around $50
The Double T Pipe Mount connects one HF stick to the center conductor and
the other to the braid using a standard SO-239 connection.  It can
be mounted either vertically (For DX?) or horizontally for NVIS.
Not having a good pole to use, I grabbed a 12' piece of wooden closet rod in the garage and clamped the mount to that.
I installed the antennas 1 at a time to the side of the mount that connects to the center conductor and tuned each to length as close as I could, then installed both antennas.  My Yaesu FT-897D with AT-897 tuner was able to check into nets in Kansas and Texas (300 to 400 miles).
This setup is very narrow bandwidth (watch the SWR on your antenna tuner as you tune up and down within the band. I was able to make contacts at 300 to 400 miles though.