Moxon for 11m...

[995]

Yes MASTER CHIEF, I was trying to get your attenion.

I'm trying to come up with a good lightweight directional antenna for mobile DXing. Not driving around, but stuck on a push pole. The main benefits I am looking for are horizontal polarization(to avoid loudmouth truck drivers and locals) and F:B ratio...what say you? How high do you think I'd have to be to get a decent take off angle?

 

[Master Chief]

Great question and I don't have an answer for you. The take off angle over one type of ground will be different than another. The next question is, where are you and what do you want your take off angle to be?

The nice thing about the Moxon is that it is lightweight! I'd start at 18' and experiment from there!

Did you see the picture I posted in the gallery for the 11-meter Moxon?

 

[995]

I had not seen that picture until now. Cool. I am in coastal north carolina. Pretty salty earth and lots of water. I was thinking a min of 18 feet...so I guess I will start there. What do I want the take off angle to be? Heck, I just thought the lower the better. I guess I'll really have to experiment now!

Have you built many? I can't decide between aluminum tubing and wire. They both have definite advantages... My big concern with the aluminum is the corner bends, but I like how it would be easier to adjust. Not sure how the bends will effect the resonance....and I don't want to end up way off freq....

 

[Master Chief]

What do I want the take off angle to be? Heck, I just thought the lower the better. I guess I'll really have to experiment now!

The lower the take off angle, the further the skip. A height that works today may or may not work tomorrow due to the ever changing height of the ionosphere.

Serious competition stations will use crank up towers to vary their height in order to maximise their signal to the desired location.

Let's say that 18' gets you into Colorado like gangbusters today. Tomorrow it may be 24' due to changes in the ionosphere. The third day it could be back to 18'. We never know!

A small lightweight 2-section tower is perfect and give you 20' of elevation to play with.

The higher the better works well for local communications, but with a horizontal antenna over real ground, there is no right answer.

As you said, its time to experiment!

I've built a few between 6 meter and 20 meter bands. I've always made them out of wire, but they were temporary installs. Did you read THIS post yet? It will give you building tips.

 

[tecnicoloco]

Hi all:
3 Years ago I built one based on an article from 73's magazine,the design was for 10 Meters,but with calculators from the Net was very easy to adjust it for 11 Meters.
70% of the antenna was built with 1/2''inch OD Copper Pipe and the rest with 14 Gauge Insulated Wire.
The antenna to my experience,was working like a 2 Element Yagi.
Will be a fun project for the weekend and you can build it with parts that you can find in any hardware store.
Materials:
1/2'' inch OD Copper Pipe
3/4'' inch Plywood
U-Bolts
L Shape Brackets
Bolts,Nuts,Washers.
Clear Coat Paint or Varnish.

I wish I have taking a picture of it,but you know some projetcs goes with out some proof,sometimes just the remains,hehehe


My 2 Pesos
Tecnicoloco
73's

 

[995]

Master Chief,

Thanks again. This is exciting. I think it's gonna keep me from getting cabin fever this winter!

I did see that post, and it's what got me interested. I've been reading everything I can on that moxon website and it's links.

Tecnicoloco,

Thanks aswell. I love hearing success stories I'd love to see a picture if you get a chance!

 

[rfoverlord]

i built one last summer out of 1/2" aluminum tubing and 3/8" solid rod for the corners and some left over plastic spacers. had it up at 16' and got into ala. from green bay Wi. with a stock 2510 first try. ran it all summer with contacts all over the map usually ranging from 500 to 1300 miles so i would say it works pretty good. i still have it but it's hanging from the ceiling in the garage. some day i will put up a 2nd tower when i finally get out of the city.