Horizontally/Vertically Polarized LPDA
After a month or so of running multiple tests with my newly constructed log periodic, and all the adjustments and tweak's having been made, I turned my attention to making the alterations to the mounting arrangement, as it had a fixed mount, positioned for horizontal polarization operations.
Now as you know, or at least I've mentioned it before, when I started down the path of developing this LPDA that covers the bands of 2 meters, 1 1/4 meters, and 3/4 meters, my interest was mainly in working the SSB portions of the 3 bands.
Of course for operating in the SSB portion of the 3 bands covered by this LPDA, the antenna had to be horizontally polarized, so therefore initially while I performed the initial testing, that is how the antenna was oriented.
Now we all know that at the end of the day, and other than operating during VHF contests or checking in on the VHF nets, there is not much activity happening in the SSB portion of the bands mentioned, so therefore it was a given that I needed to make a mount that allowed the antenna to be positioned in either the vertical or horizontal position, as with most of the activity on the 3 bands being in the FM segment of the band, the antenna needed the option of being able to be used vertically polarized.
So with time spent in my shop, I developed the mounting arrangement seen here. The mount consists of a double-ended ball-joint with both ends attached to individual Lexan plates that individually mount to both the antenna, and also to the Max-Gain systems mast assembly.
This ball-joint assembly has a adjusting-knob located in the center of the assembly that allows the antenna to be positioned horizontally or vertically, and then the antenna is secured by tightening the locking knob once positioned correctly.
Its also important to mention that the Lexan mounting plate located on the antenna is optimally located on the balancing point of the antenna, so that the antenna does not have a tendency to want to tip towards either end, introducing unwanted loading on the ball-mount.
If you were to un-tension the clamp, the antenna will stay in the position as set (at least when set in the vertical position).
Of course it goes without saying that the components that make up this mount assembly consist of composite materials for the most part, so not to distort the radiation pattern of the antenna,
Now lets be clear that this mounting assembly is meant to be used with a antenna that is being operated as a temporary setup in the field, and not to be mounted permanently on a tower or a tripod on the roof of your house.
With the LPDA mounted permanently on a tower or tripod, I would make a more robust adjustable mount utilizing a 12VDC linear actuator, providing the motion required to re-position the antenna vertically or horizontally as needed.
Now you know the rest of the story.
Click on the photo for a closer look.....
A closer look at the mount positioned on my Max-Gain push up mast.....