Tomorrow starts my Helical antenna project

[Pro-95]

So I went down and got some homebrewing antenna making supplies. Spent 14 bucks. Got a 4"x10' hunk of PVC for my "mold" or "tool" to spin the helical section. Bought another 25' of #4 solid copper.

The plan is to keep the helical section on the 4" tube for now while I play with the spacing and tuning. Once I find the "sweet" spot I'll pull the tube and place it over a smaller tube with spacing/centering pins. I'm undeceieded over the center tube material. Both PVC and wood dowel have their respective good and bad aspects. PVC is relativly light and is easily adaptable to drilling in studs for the centering of the heliax. A wood dowel is structually superior but adds complexity to the dowels. Both have a limited life span with PVC failing sooner due to elements and UV deteriotion. Wood will last longer but would tend to bend or bow in a long application with support only at one end. If I've missed an option please feel free to jump in.

On the reflector I'm considering spinning the #4 copper in a diminishing pattern and using soldered in place copper supports. Since I've seen most reflectors although starting as a solid plate ending up with several holes in them to reduce drag.

The overall length I'm shooting for is +8' but will do incremental spins to see if a happy medium can be acheived with a shorter lenght reducing the need for structual strenght and the weight associated with it.

I will conduct a small test spin on the remant sections of #4 I have to see how far I can go unsupported before the weight exceeds the integrity of the #4 alone.

Any thoughts on the materials is accepted.

 

[JohnN]

Just paint your PVC with White Enamel paint from a spray can, and that will stop the sun from deteriorating the pvc. Works great down here in Las Vegas (we get more heat than you) and I use it on all my "J-Pole" antennas for ham work.

 

[N_Jay]

What are you trying to receive that you will be using this antenna for?

 

[Pro-95]

Just paint your PVC with White Enamel paint from a spray can, and that will stop the sun from deteriorating the pvc. Works great down here in Las Vegas (we get more heat than you) and I use it on all my "J-Pole" antennas for ham work.

What brand of white paint are you using? The ones I've found have metal particles in them and would adversly effect the antenna? J-poles? Where were you when I was building mine?

Welcome to the list John, It's good to have another builder on the board.

 

[Pro-95]

N_Jay, Building it for experimentation and to use until I clean out my garage and get a drill press so I can build a more permanent version of my long beam Yagi-Uda. The PVC version isn't as sturdy as I'd like since we get 90MPH winds around here on a regular basis. The really long beam I made out of wood is too heavy to mount on a mast, besides I don't like the "looks" of it. It was however a good experiment.

Now that the helical antenna is coming together I'm probably going to build a short one for my GPS and design it around 1579Mhz to grab satellites while in the forest.

 

[N_Jay]

N_Jay, Building it for experimentation and to use until I clean out my garage and get a drill press so I can build a more permanent version of my long beam Yagi-Uda. The PVC version isn't as sturdy as I'd like since we get 90MPH winds around here on a regular basis. The really long beam I made out of wood is too heavy to mount on a mast, besides I don't like the "looks" of it. It was however a good experiment.

Now that the helical antenna is coming together I'm probably going to build a short one for my GPS and design it around 1579Mhz to grab satellites while in the forest.

A helical for GPS probablt won't help.
You need several satellites, and te narrow beamwidth antenna might get one or two, but will have lots of trouble getting more.