Tag Archives: Cobra UltraLite Antenna

WSPRlite on 80m

After a fair amount of work yesterday I was able to get my Cobra UltraLite Senior back up with some assistance. As I said in my previous post, the tree that was holding the north end of the antenna had to come down so I needed to develop a new support plan. The other trees in the area weren’t completely suitable so my XYL suggested using the post for the basketball hoop as a support for a pole to support the antenna. I was going to fabricate a pole but a little further thought resulted in the purchase of a Channel Master 25ft antenna mast. The next problem was to develop a method of clamping the antenna mast to the basketball post. After a few minutes consulting with my older son, W9KKX he suggested using back-to-back muffler clamps. I acquired a set of three 4″ clamps and three 2″ clamps and W9KKX welded them up for me.

Clamp construction

After a little bit of paint I had three, custom pipe-to-pipe clamps:

Pipe-to-pipe clamps

Attaching the clamps to the basketball post and in turn the antenna support mast was very simple and clean.

Pole and mast

It was very easy to then push-up the mast by simply placing a ladder next to the basketball pole and running the mast sections up.

New antenna support

With the trees so close to the basketball post it actually blends in quite nicely. I placed some guy ropes from near the top of the mast to the trees behind it for support.

After replacing the halyard and support ropes in the tree at the south end of the antenna I was able to pull the antenna into position with the assistance of my younger son and one of his friends. The antenna is 140 feet long and runs over the course of about 200 feet including the support ropes in order to get the center feed ladder line positioned well. The south end is at about 35 feet and the north at 25 feet. The center feedpoint is supported with a line to another tree just to the west of the antenna. The antenna is oriented NNE to SSW.

Once the outside work was completed I went inside to check the antenna with my AA-55 Zoom and then configure the WSPRlite tranmitter for 80m. Since the Cobra UltraLite Senior is not resonant on 80m I used my Dentron Jr. Monitor to provide a match for the WSPRlite transmitter. With these preparations complete I started WSPRing on 80m with 200mW.

KA9EAK @ 200mW on 80m

Band conditions

Over the course of the night I was watching results and comparing with some other local stations. For example the station of AA9GE is just under 200 miles south and a bit west of mine and he was getting these results with 1w of power:

AA9GE @1W on 80m

The overall activity looked like this:

80m WSPR activity

A lot of the spots from Europe were US receive stations. There weren’t a lot of US stations being received by European stations with the exceptions that I found running 5w as opposed to 200mW.

WSPRing is very interesting. There obviously are a number of variables involved from propagation conditions to antennas and power. It’s not everything, but it’s something. Now that I have my Cobra UltraLite Senior back up I can do some A\B testing with my Hustler 4BTV. I’ll post results when I have them.

Now to finish up my Thirteen Colonies. I’ve got four more to go plus the GB13COL station.

Happy Independence Day!

 

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