Thursday, November 16, 2023

H44WA and VDA's

My friends on the Solomon Islands operating H44WA are having a good time working the bands.

They have been operating now for about 24 hours (almost) and the Livestream results so far have been impressive.

Nearly 8,000 Q's in the first 24 hours and it's going well it seems.

I admit that what has been on my mind was the operation of 10 meters and 15 meters using the VDA's I put together for them.  I had a good feeling that they would work since we tested them on the beach at Golden Gardens in Seattle (just a jaunt north of Shilshole Marina).

Justin, K5EM did a lot of work to optimize the lengths of the sections so that when it was assembled, the SWR was low and the radiation far-field pattern was lobed out in the direction of the Director Element (in the case where the Director was selected by way of jumper wire on the Parasitic Element).

Now that the Team is on H44WA, and I'm watching the spot-clusters I am glad to see reports of "Loud" in the comment section.  It has a lot more to do with their power amplifiers than the antenna -- but nonetheless, the telemetry I got back from the Team privately was that the SWR was matched to nearly 1:1 which is great.  In the modelling of the antenna the take-off angle was around 10-12 degrees too.  These are special antennas - the VDA - and they are made to work near salt-water ground.  There are no radials (necessary).

As the Team operates I am also trying to find the chance to work them on the other bands too.  I was glad to have them in my log for 12 meters (worked off a VDA made in what we call the "French Design" -- which is a single fiberglass mast with a rhombus shaped wire driven element and parasitic element).  That French Design is effectively "steerable" because there is only one mast and the DE/PE are always attached to the single mast.

The other VDA they are using is the 20 meter (Again, of the French Design).  The VDA I gave them were for 15 meters and 10 meters  -- and those are two element versions so they are not "steerable" -- the Parasitic Element is fixed to the ground as is the Driven Element.  But the beam-width of the VDA in that design is at least 90 degrees so all one has to do is point it North from the shore of the beach and they can work easily both Asia and NA/EU fine short path.  The hind-quarters of the pattern (VK/ZL and SA are another matter -- I think it will work but it won't have as much gain in the rear quarters).

While they are working on their operation, I'm back at the NEC2 software and optimizing the next generation of VDA that I will be making.  Despite the protests I will still try to make the 30 meter version and also a 6 meter version.   But the main set consists of 20m through 10m.

I look forward to the Team working 30m and 40m when I can hear them.  At the moment, they are working mostly grey-line so I think that when the sun begins to set across NA I should have a shot to work them at the low bands.

I also gave them some guy-rings to use for guying the antennas.  They were made to slip over the tube but not fall down past the larger OD tube.  There were three chamfered holes on each ring to tie off their paracord/guy line.  Ignore the blood.  I had 20 minutes to make these before Rob had to jump to the airport the day they left.


Here is Rob N7QT and Tom NU7J are getting the 10 meter VDA up.



Delrin makes a great insulator material.  Strong and Lightweight.  Easy to machine and will not be affected by salt-water or corrosion.   




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