J-Pole: Surface and composition of elements

[Need2Know]

I'm considering building a J-Pole antenna. Rather than threading the ends of blank rods, I am thinking about using the pre-threaded rods (threaded for the entire length) you can buy at Lowes/Home Depot/Ace Hardware. That way, all I need is a nut on each side of the L-bracket to fasten the rods, plus the requisite antenna connector.

The question is this: Will the threaded surface (as opposed to a smooth surface) of the entire length of the rod have any significant effect on propagation of the anteanna?

Question 2: With the entire rod threaded, the rod can be adjusted up and down on the bracket. Is the critical length of the rods the distance between the bracket and the top of the rod, or the total length of the rod, both above and below the bracket? Here I am speaking of the secondary rods, not the one with the antenna connector.

 

[W5LZ]

The threads on that rod will make no significant differences. As with any antenna the length/diameter of it's elements will have some affect on where it is tuned for (where it's resonant). And as also with any antenna, making some 'tuning' adjustments is normal.
Will any 'rod' below the mounting bracket affect the antenna (talking about a 'J'-pole)? It can. What kind of affect? I've no idea, never done that before. So, try it and see, then adjust accordingly. (Small lengths shouldn't have any significant affect. that 'small' is in relation to frequency wave lengths. The point where that 'small' becomes significant is sort of 'unknown', who'z done that sort of thing before??)
- 'Doc

 

[Beetle]

Experiment and learn!

 

[Need2Know]

Thanks. I will.

A good antenna tuner couldn't hurt, either. Any recommnedations? Actually is there any such thing as a 2meter/70cm antenna tuner? I didn't notice any on MfJ's web site. If there is, I guess it would be pretty pricey.