Vertical Beam?!?

[ToddDubya]

K4OGO posted this on twitter and it got me thinking. This would be easy to build, and you could have spreaders at the top and bottom and just hang the thing from a tree. A rope off the front side to turn and aim, and you're in business. I put up a DxCommander (vertical) last summer that is just fantastic; I'm sold on verticals. Why didn't I think of this?

A few commenters suggested a Moxon instead, which would be smaller. With 16# wire, you're looking at about 5' shorter. This could easily be built with spreaders top/bottom as well (rotate the antenna below 90 degrees and hang from ends). I think I'd add strain relief for the coax, too. It's supposed to be cold as shit today, so it might be a fun project.

W4/VP9KF - Results - Moxon antenna design calculator

View: https://twitter.com/SaltyWaltHudson/status/1621250200709783553?

 

[ToddDubya]

This guy has the right idea.

http://www.vvarc.net/files/Antennas/PortableverticalMoxonfor14Mhz.pdf

 

[mcb]

I was just reading about this 10m moxon, once I get out of my apartment I want to experiment with one, and raise my hustler vertical again.

 

[n1oty]

I ran a Moxon-type homebrew design on 10 meters back in the mid-90's, but in a horizontal polarization. It worked well. I even used it to break the pile up on the 1997 Heard Island operation with a 100 watt radio. I'd say it performed just about the same as any two-element antenna. The real satisfaction was in the homebrewing of the antenna.

 

[UJay]

We've used 6m MOXON for rovering during VHF Contests- The first year we were aiming it backwards and was wondering why everything was stronger off of the back....

My 40m MOXON was comparable to a full-sized 3-el 40m beam.

I am a big fan of MOXON beams...... Horizontal on the high bands may work out better for you though....

Do it!

UJay

 

[ToddDubya]

Haha, yeah the aiming is counter intuitive.

The idea of vertical for me is for ease of setting up and aiming. I'm sure I'd use it at the house some, but the main use case is portable/woods operation. I figure I can make it out of three wires, a couple spacers, two lengths of PVC or driveway markers, and some cordage.

I should really get a mast of some sort up at my super secret squirrel location and then I could put up a horizontal or two.

 

[ToddDubya]

Well I went for it. I have all the parts made minus tuning the driven elements. Hopefully it tunes up relatively easily.

I had almost all of the parts on hand except for some #6 hardware, so it was almost free. I guess the proof will be when I see how it performs.

 

[timbo]

I ran a Moxon 6 meter antenna for quite a few years and I was quite impressed by the results. Just about every station I heard, I could work. Unfortunately, it came down in an ice storm. I still have the fiberglass spreaders somewhere.

 

[ToddDubya]

Well my simple setup proved to be not so simple. I tried to get it set up and tuned today, but because I was trying to hang it from a single point, it would never balance. The weight is not centered because the driven/reflector elements aren't the same length, and the feed point is on one side. After thinking about it for a while I decided I needed to hang it from the ends of the top spreader, which it turns out is exactly what people do. I wish I thought of this when I was at home with access to tools and a non-snowy workspace, but I did not.

Instead I had no choice but to light a fire, smoke a cigar, and enjoy the boring quiet woods. What a rip.

 

[ToddDubya]

Well that's a fail for today. I hung the 10m vertical moxon up from a tree and the SWR dip is way too high, so I'll need to stretch the wires.



Thinking maybe the trunk was a factor (or that the bottom was so close to the ground), I pulled the bottom out away from the tree. A little better.



Then thinking maybe me holding the bottom was a bad idea I put a string on the bottom to pull it away from the trunk and that worked too. I also lowered the top a little to give me more room to pull.



I would have liked to get the bottom 1/2 wave above ground, but I don't have a sturdy enough branch high enough up to do that. Once the snow is gone I can try again in the woods and see what I get. If worse comes to worst I can figure out how to reconfigure it as a horizontal and maybe that'll work better.