Before securing the mount to the aluminum rod, I used a file to put a point on the end that goes into the ground. I also roughed up the area that the mirror mount clamps to with the edge of the file, to help ensure a good grip.
Because the bolts which came with the mirror mount were a little larger in diameter than the machine screws I'd used with the homebrew mount, I had to replace the ring terminals on the radials with spade terminals.
Click on any pic for the full sized version.
I used the original nuts that came with the mirror mount when putting it together, then used two 1/4x20 wing nuts to hold the radials on.
The finished mount with the collapsed MFJ-1979 whip:
Closeup of the mounted whip and deployed radials:
And finally, the whole shebang, now standing tall even with a slight breeze:
The FT-817ND tuned to 14.070 MHz running 5W QRP powered by a 12V SLA battery*, and my iPad Mini 2 running PSKer, tied together with KF5INZ's Easy Digi interface:
The temp today on my back patio in the shade was in the mid-30s and it starting feeling rather cold. I received signals from as far away as Michigan. I called CQ several times and almost completed a QSO with a ham in Georgia but there was too much QRM. But here's where pskreporter.info showed my signal reaching, from my home near Philadelphia, PA:
All in all, I rate this HF vertical as a success for portable 20M ops. I received many PSK-31 signals and got my signal out into the midwest. I'm looking forward to nicer weather when I can take the rig with this antenna to a nice hill and try for some digital QSOs.
Update 1/20/14: I got the battery working. AR15.com's Harlikwin messaged me about this, prompting me to look at it again. It turned out that I had the Power Pole connection on the negative side was bad. The little tab inside the PP wasn't fully seated. I was able to disassemble the PP, reseat it, and verified that I can power the radio from the lithium battery alone. w00t!!!!!