Amateur Radio - Cobra Ultra Lite Sr.

Dipole - Cobra Ultra Lite Sr.

My thinking was that since I have the tower, I might be able to hang an inverted "V" from the tower and being a bit higher and further from the power lines than the current Maypole, it just might work better. So I first made a simple antenna cut for 75m so I could test the location and compare it against the Maypole. My brief testing period showed that it played as well and often a little better. It was also a hair quieter. Knowing that it would work and maybe even better than the Maypole, I found this Cobra antenna and the reviews were almost all positive. After talking with the builder a couple times, I decided to give it a try. Unlike some other antenna companies I've dealt with, I also want to mention that Joe, the builder of the antenna, was always available and helpful when I called. The senior model is 140 feet long with 100 feet of 450 ohm ladder line. It requires a tuner and will tune from 160m to 10m. I bought mine from Ham Radio Outlet for $89.95 along with an MFJ-912 remote baln that Joe recommended for this antenna since I didn't want to bring the ladder line into the house.

The Cobra Ultra Lite Senior as removed from the package. Also included is a single page instruction sheet.

First I needed a non-conductive stand-off arm to hang the dipole from. I bought a 1 " x 6' fiberglass rod and mounted it so that it can swing from side to side for self centering and uses 2 pulleys to minimize down-force at the end of the rod.

Close-up of the mounting hardware and second pulley. The "T" fitting is loose so the rod can swing from side to side.

Here it is installed and hanging from the fiberglass rod as viewed from the back side.

Fabricated this bracket to terminate the ends of the rope that support the ladder-line that is suspended above the roof.

Ladder-line suspended over roofTop section

I don't know if this is the best way to deal with the excess ladder line but it's what I came up with.Joe informed me that I could cut 25 feet off the line but ideally, the full 100 feet would allow it to tune easier. Rope is strung between the tower bracket and the chimney. The ladder line is looped around the two parallel ropes and tie-wrapped in place. There really was no other convenient place or way to "use" the extra ladder line. The loops are spaced 2 feet apart and hopefully far enough apart to minimize any effect that this "coil" may have. Don't know for sure but it seems to work just fine. Looks "interesting" too...

The whole thing from the chimney to the tower.

Looking from the tower towards the chimney.

Looking down the center.

MFJ-912 baln and PVC sprinkler pipe and fittings painted black. This makes a great stand-off. The 1" "T" fitting is a perfect fit for the 450 ohm ladder line.

Another view of the baln and stand-off. The coax run is a bit long at 37 feet.

This is the end that terminates in the backyard at the fence.

The other end is unfortunately in the front yard. I originally used the county street sign for my tests and then planted the 10 foot 4x4 to get it up out of easy reach of the school kids walking by every day. As you can see, this antenna barely fits on my lot.

Looking up from the back yard.

The view from the driveway at the street.

And finally, here is what the neighbors get to look at.