I've had (surprisingly) good luck with aluminum fencing wire for top band elevated radials - 8 x 125' in a forest with a lot of falling debris. I used 12.5 ga, and its been up 3 years. 9ga is also av
Tractor Supply has 1/4 mile rolls of 17 and 15 ga Al fence wire. Had an 80 inverted V up for 5 years. No extra stretch, but not under extra tension. Used it to hang deer net between post for the gard
I've used aluminum fence wire for antennas for years with never a problem. I've used it from #17 to #10. Works just fine. I hook it to copper using electrical wire nuts squirted with anti oxidant gre