Interesting use of "controversial items" as easy tuning aids. I would suggest, though, that you solder them to the antenna legs rather than using a grease. I wouldn't be very concerned about dissimilar metal corrosion as the brass is at least 70% copper with the rest being zinc and other trace metals. Brass and copper coexist quite happily, especially when there isn't a liquid trapped between them. I would, though, be concerned about movement of the tuning device over time (they could conceivably rotate due to wind induced vibrations) so I would counsel that you use a brass jamb nut at the very least (solder is better). BTW, painting the PVC is a very good idea as PVC is adversely affected by UV and degrades in sun light. Painting does provide a level of protection. Using the grey conduit would be better for outside use as a lot of those PVC formulations have some included UV protection.
I have a plastic deck chair that I painted with oil-based enamel years ago. Several unpainted chairs have become brittle and broke while the painted one soldiers on. The resins in plastic that keep it flexible can be prolonged in this manner. Fresh cast plastic should cure for a few weeks before painting though.
@@ricksshop Yep, it is well known in the power industry that white, plain PVC used out doors will need to be replaced in several years (like 2 -3) due to failure. Not only do the plasticizers leave the PVC (which results in brittleness) but the UV from the sun breaks the polymeric chains - which leads to even more brittleness. The grey conduit type is more resistant to the UV. BTW, I must have missed the gauge of wire that you used and what thread series you used for your tuning devices and antenna.
This antenna you made isn't a collinear antenna, it's a vertical dipole antenna, with unity gain and probably more "directional" than omni-directional. You could take two to four of them --- with a phase harness --- and make a dipole array positioned each pole in a 90 degree off set of the others and have a omni-directional dipole array antenna that might get you about 4 to 6db gain... JMHO that is.
If I was feeding it with 200 Mhz, you would be correct. However, at the intended frequency of 465 Mhz, the legs of this antenna are a half wavelength long. It's essentially two Siamesed 465 Mhz J antennas rotated 90 degrees. See: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-YFMyYQcY53g.html
When I want flat SWR curves for UHF/VHF I use thick elements. 1 inch aluminum is amazing, as is copper water line, even refrigerator line has substantial diameter. I like the (3)1/2Wl design!
There are two problems with plastic conduit. One, rumors of signal attention, and two, it's not as uv resistant as one might think. I have some outside my house that has discolored and buckled over the years.
Rick, I built similar antennas for GMRS, 70cm, and 2 meters. It's basically an extended Zepp. I used 1/8" stainless steel tig welding rods to make the antenna. Each element is 15 3/8" x 3 1/2". Keep the 3 1/2" pieces separated by 1 1/2 inches, this will be your tuning stub. I used copper mechanical lugs purchased at home depot to slide over the stubs. Coax end is spit terminal lugs are added to attach to mechanical lugs and secured with nut an screw. Slide the mechanical lugs on the stubs to adjust VSWR. Flat VSWR on the entire band and easy to tune. I hope this made some sense. Mike
@mikeguard5693 A DIPOL IS A DIPOL .. COLLINEAR AIN'T A FREAKIN DIPOL ZEPP MY FOOT ... PLEASE POINT IN ARRL AND TELL ME WHEN A ZEPP WAS A DIPOLE.. AND THAT WAS A COLLINEAR... A DIAMOND X300 OR COMET GP6 DIAMOND7900 OR COMET7900 THEY ARE STACKED COLLINEAR ANTENNAS... COLLINEAR MEANS ON TOP OF EACH OTHER THER OF THE NAME COLLINEAR .. OR DIPOL COLINIAR DIPOLES GUESS WHAT MAKE THEM COLINIAR THEY ARE STACKED ONTOP OF EATCHOTHER... WEEEEEE WHEN M0R0N´S PRETEND THEY KNOW EARTH IS FLAT... YOU GET A """SINGLE STACKED COLLINEAR DIPOLES..""" WORD SALAD
From Wikipedia: A collinear antenna is "an array of dipole or quarter-wave antennas mounted in such a manner that the corresponding elements of each antenna are parallel and collinear; that is, they are located along a common axis." This one is 3/2 wavelengths long. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-YFMyYQcY53g.html
