You could use any copper wire but note that pure copper wire will stretch over time more that what I am using. When wire antenna's stretch that also de-tune downward in frequency as they become longer.
The bronze wire is extremely strong and will last a life time, I'm sure it's weight rating is way over 1000 lbs.
For this antenna you will need two pieces of wire 26Ft long. 25.5 is the finished length aprox. I have extra to get around the insulators and to wrap and solder.
I chose to use ceramic egg style insulators for several reasons. Most of you would look at these and say WOW that is overkill! First off I chose them because they were all I had in the junk box and I didn't want to invest more money at the time.
I also wanted to have insulators that had weight to them so I could put one end of the antenna elements over a tree limb if there was an emergency or I was in a hurry if needed. This way if it was bad weather I could let it hang and not need to tie it off as I normally would do.
Since the insulator electrically separates the RF energy on the antenna element/wire from the non conductive support it needs to keep the two from touching. Often when transmitting on certain frequencies there will be a very high voltage at the outer ends of the antenna. This voltage can start a fire or melt a plastic insulator if not installed correctly or the wrong insulator is chosen for the job.
It is not impossible to have several thousand volts at the end of an antenna. NEVER touch an antenna while it is in use unless you know what you are doing!!!
I chose a 4way 1/2" pvc junction as my center insulator. I did this mainly to facilitate supporting or hanging the antenna from the middle (which should always be higher than the ends.)
With this insulator I am able to insert 1/2 pvc pipe to support from under or over the antenna to hang from, how ever I choose. Use your imagination on this and you can dream up a number of ways to support this antenna.
I will use a piece of 550 Para cord run through the open ends to hand the insulator allowing the Ladder line to drape downward to the ground. It is advisable to hang this antenna as high up as possible. Getting its at least 20 feet up on a tree branch or some other non conductive support would be suitable.
The Ladder/Window line is aprox 450 Ohm impedance. You will be using 16.5 ft of this line. I suggest cutting it 6-8 inches longer so that you have room to make attachments with solder at both ends. With the use of an HF tuner between the transmitter and the antenna any finished length between 15.3 and 16 Ft should give you a good SWR match on all bands.
Lastly (NOT SHOWN) you will need a piece of 50 Ohm Coaxial line. RG-8, RG-8x, RG-58U will all work depending on the wattage you plan to run with and the length of the cable, and loss you want to incur. An RF fitting to match the antenna output of your tuner will be needed these are usually PL259, N type, or BNC connectors.