Dual Band 144-440 Vertical (ARROW)
Another design I found online I decided to try and build. It worked out VERY well. It is somewhat tall for an inside apt antenna but it worked out very well on performance and SWR for both the 144 and 440 bands.
You have to take several lengths of 3/8" aluminum rod and thread and cut them. Use the following guide for length and spacings. I used a SO-239 Stud mount to mount the driver element to the angle bracket.
The SWR was very good and very broad as the following plots I made show.