Thoughts on building a Moxon

[cjruger]

Actually I already have a prototype made up from my wire dipole. I just folded the ends at 90 deg. use zip ties at 4" and made the reflector to proper length for ll meters. I set it up using wood stakes on the ground about 2 ft up and had a perfect match, however didnt get much but a couple local reports on it. I have a few thoughts and questons.
-How will this compare to my 5/8 groundplane antenns which seems to work great right now. not sure what gain it might have if any over the 5/8 and is a simple single element moxon an upgrade?
-can a moxon be used vertical is there an advantage to it over a 5/8 GP
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I dont have a tower or and roof mount is out of the queston, trying to keep stealthy. current antenna is in a tree, thinking of trying Moxon in the tree about 20-30 ' up. It would be fixed to the Sor west for trial and as an alternative horizontal to my 5/8 vertical

 

[camaro1]

besides from having to figure a way to rotate it in the tree,,,, horizontal is always nice to have as an option when skip rolls in

 

[vkrules]

here is one a local did

 

[vkrules]

Tried to upload the photo and ended up with the whole pdf. I love those squid poles for ant work.

 

[cjruger]

what sort of gain is ther over a 5/8 vertical? is it worth it?

 

[vkrules]

Not wanting to start an argument. But if both ant are vertical 1/2 an s point at best,and that is assuming they are at the same height. The big advantage is being able to turn away from noise and interference.

 

[wavrider]

Two element moxon has WIDE bandwidth and has uniform gain across the usable band width.

I will have around 4DBD BIG improvement over the ground plane

http://www2.mmae.ucf.edu/wiki/Moxon_antenna

http://www.hpsd.nl/f-yagi/2el-moxon
Henry's site

So to answer your question the 5/8 wl may have 1.1 dbd gain.

The moxon will work better and have rejection

 

[M0GVZ]

My Moxon could hear stuff quite strongly that wasn't even there on my Imax 2000. That and the >20dB F/B which will massively attenuate signals you don't want.

vkrules, as you correctly point out used vertically you'll see not a lot of difference. However horizontal antennas benefit from ground reflection gain which makes a huge difference. I'd not really bother with a vertical version.

cjruger they're definitely worth it. I used mine on 10m band in the CQ-WW-SSB contest and even at just over 20ft high worked China from the UK longpath with just 100W, a distance of over 18,000 miles. That weekend I had 502 contacts in 91 countries in just 16hrs of operating.

 

[cjruger]

Cool, thanks. I made up a prototype moxon out of copper. 1/2" pipe. Testing in the ground about 6 ' up.with moderate dx conditions on am, I had several contacts from here in NY to New Mexico/Arizona/ California.
This thing is extrelt akward and hard to move around and my temporary testing mast(2x6x6') fell over 3 times now and is doing a number on the sumitro of the rectangle. I noticed a little bit out if evenness affects the swr..
The biggest setback i have is trying to keep it somewhat inconspicuous and able to rotate it. It might end up being something i have on a portable or take down mini boom for when I'm not using it

 

[mb91w126]

Cool, thanks. I made up a prototype moxon out of copper. 1/2" pipe
This thing is extrelt akward and hard to move around and my temporary testing mast(2x6x6') fell over 3 times now and is doing a number on the sumitro of the rectangle. /QUOTE]

Agree on using pipe as construction material. Father was a plumbing contractor, so everything we constructed was made from pipe. I used 3/4 EMT and it's far heavier than expected but very easy to assemble. I need to reenforce the feed point as its flexing more then I expected.

What did you use to gap the feedpoint??

 

[cjruger]

well i wasnt sure what the gap was supposed to be so i took a block of wood and drilled a 5/8" hole in both ends and slid the pipes into that but that broke when it fell down so i machined up a plastic delrin round with 5/8" holes and mounted it like this with around a 1" gap between the ends

 

[M0GVZ]

The gap for the feedpoint isn't massively critical and 1" is fine. Interesting feedpoint construction there.

 

[cjruger]

Im not impressed with testing of it. plus the copper is a bad idea, its too much flex and heavey. I need to find some aluminum tubing, any idea where to get it, Home depot does not have it.