Magnet wire - Cheap and easy to find but tends to stretch and break under its own weight.  Good for hidden antennas if they are supported at multiple points.

Copperweld - Steel wire with a heavy coating of copper very strong and as good conductor as solid copper, because of skin effect.  This wire is very stiff making it a little hard to work with.  I generally think this type of wire is the best wire for antennas when you consider the cost.  Cost is under $0.20/foot

Stranded copperweld this is strong enough to be used as guy wire. Can be found at $0.50/foot

TWA - This is the top of the line copperweld wire designed to be trailed behind airplanes this stuff is tough and flexible. (At least that's what the ads say) Can be purchased around $1.50

Copper Plated Aluminum - I have only read about this stuff, but should make a nice antenna.  Light weight, good conductor and moderately priced. Comes in 1/8" and 1/4".  But the question is will it stretch? Under $0.20.foot

Phosphor Bronze very flexible, very strong highly resistant to corrosion.  If you have a salt-water corrosion problem this is the wire for you.  Can also be used for guys. Generally can be found for less than a dollar a foot.

Litz wire - This is a special woven wire design to reduce skin effect.  It is used to make hi Q coils.  This wire is both hard to find and expensive.  The weave gives added straight to the wire, some types have a steel core to support the wire in antenna application.  Small gauge Litz wire can be useful for temporary antennas because it tends not to kink and very flexible.  But it is not strong enough for a permanent antenna.  I built an 80M dipole antenna with 7x36 Litz which worked very well but the Michigan fall winds knock it down in just a couple of weeks.  If it was not for the cost I would use the steel reinforced Litz wire for all my wire antennas.

Coax Cable just about any coax cable can be used to build a wire antenna.  You can just forget about the center wire, (I like to solder to the braid at each end so the center conductor will add to the strength of the cable.) the outer braid will be the antenna element.  Beware of old coax the braid may very well be corroded. This is another good wire for corrosion areas because you can seal up the coax at both ends.  The larger diameter of the coax over other wire will help increase your bandwidth.  This is probable the only descent wire for wire antennas that you can buy at Radio Shack (I would not use it as coax myself).  Under $05/foot

The main purpose of an insulator is to block the flow of electrical energy and to provide support to the antenna and some time the tower.  There are two main types of insulators used in wire antennas strain type (sometimes call egg type) and non strain.  The strain type is design to not only to provide support to the antenna but to help support the tower.  Strain type insulators are designed be part of the guy system of the tower, and are designed so that when they fail the cables that pass through them stay interlocked, keeping the guy from failing. Non strain insulators just have to support the antenna, and when they fail the antenna falls to the ground.  Which should you use?  Well that depends, if your insulator breaks what falls?  If its not dangerous you can use the non strain type otherwise you need the protection of the strain type insulator.
The only disadvantage of using a strain insulator is that they typical have a lower arc-over voltage, but unless you are running high power it will be a wash.

Bumps and ridges on insulators are there for a couple of purposes one is to increase the surface distance between the ends of the insulator to increase its arc-over voltage. Two to help encourage water run of and not flow between the ends again to help stop arc-over.

Probable the best material to make insulators from is ceramic and glass both are very tough materials and both resist arcing.  The next most common materials are Bakelite, Teflon and other plastics.  Plastic are generally pretty good insulators but some types will break down to carbon during and arc-over this should not be a problem for most amateurs uses.  Wood can be a pretty good insulator but it must be protected from moisture with several coats of varnish, generally I do not this is worth the work.

You can make a pretty good antenna insulator from materials from around the house or stuff easily obtained from the lumber yard or hardware store.  PVC pipe and Plexiglas sheet are two common and easily worked materials, PVC is a bit more forgiving Plexiglas will often crack when drilling or sawing.  To make an insulator, make a strip of Plexiglas 1 to 2" wide and 4 to 8" long or a piece of PVC pipe 1/2 to 1" in diameter and 4 to 8" long, and drill a hole through each end.

Now if you are not using a balun than you can just use a piece of PVC or Plexiglas as the center insulator adding a hole in the center to attach your feed line.  But if you are using a balun you need some kind of housing for it.  I have seen pieces of PVC pipe and end caps used for this, and they seem to work real well, but if anything goes wrong you need to use a saw to open them.

I think I have found a better solution at the lumber yard I found among the plastic conduct accessories a plastic junction box with cover and gasket.    This Junction box had four ports for connecting conduct to the box.  3 plugs where supplied with the junction box and I glue these in place and seal the fourth with silicon rubber sealer.  I then drill three holes in 3 of the ports and mounted  #10 eye blots for attaching the antenna wires and the third for attaching the center insulator to a center support.  Large washes where used to get better support on the inside of the junction box the material that the plugs are made from are thin.  In hindsight it would be easier to mount the eyebolts between the ports instead of in them.

 A hole was drilled in the back of the junction box for a UHF connector and two holes where drilled to allow the output wires from the balun to connect to the antenna wires.  Next the balun was soldered in place and the cover plate was screwed down.

Sealed Center Insulator
 
 

Trees, Buildings and other structures make good spots to hang an antenna from , the problem is usually how to get up there to attached the antenna.  With building this normally means a ladder or hanging out of a window.  With trees ladders are usually way to short so we have to resort to climbing ( an activity that I always though was dangerous when I was young) or throwing.  Now there are ways to throw up an antenna that can get you up a lot farther than your arm, I used a bow and arrow and I have seen people use wrist rockets.  The easy way to use a bow and arrow or wrist rocket is to use them with an old fishing real with a light line.  Attach the line to an arrow or a weight and shoot it over the branch that you want to use.  Use the light line to pull up you guy line for the antenna.  Another method I have heard of is to fly a kite with and extra string dangling from it.  Fly the kite so that the main string goes over the branch you want to use and then have your assistant pull the kite down with the second string.

Baluns are used in an antenna system for two main purposes, the first is to help match impedance, the second is to convert from balanced to unbalance and back again systems. Other uses include combiners and phase reversers. Now most of us have experience a mismatch of impedance in our antenna system at one time or another, the standing wave ration goes up and the antenna system converts RF to heat instead of launching it on its way. The standard balun configuration can change the impedance in fix ratios with 4:1 or 9:1 the most common. Other ratios are possible with more complex windings
 
 
 

	50 W System	75 W System	50 W System (reversed)	75 W System (reversed)
4:1	13W	19W	200W	300W
9:1	5.5W	8.3W	450W	675W

 

The other main use of a balun is converting bark and forth from balanced device to unbalanced. This is an important operation because nearly all transmitter and receivers produced in the last 40 years are unbalanced devices, while most of your antennas are balanced devices. Most transmission line used today is unbalanced (coax cable) but ladder line is still sometimes used which is unbalanced. While it is possible to get a good SWR without converting from unbalanced to balanced this will create distortions in the antenna pattern.

Do You Need A Balun?

A balun is just one of many tools to get a better match of the various elements of your antenna system. If you look at the chart above you will see what the common balun configurations can match to. A 200W or 300W impenance suggest a good match to a folded dipole. The 450W is right on for 450W ladder line. If your antenna already has the same impedance as your transmission line you do not need a balun for impedance changing.

You may still need a balun to convert from unbalanced to balanced using a 1:1 balun. For example you put up a wire dipole antenna, which typically has an impedance of 50-70W, a 1:1 balun will balance the antenna currents so that the whole antenna is properly exited.

Some other methods of converting from unbalanced to balanced are:
 

	Impedance Matching	Balance conversion
Stub balun	Ö	Ö
Delta Match	Ö
Gama Match	Ö	Ö
Omega Match	Ö	Ö
Folded match	Ö
Q Match	Ö
1/2 wave stub	Ö
T Match	Ö

 

Balun Configurations