Copper tube or aluminum tube ?
The losses of an aluminum radiator can be 4db worse compared to a copper radiator of the same thickness.
After calculations using loopcalc.exe :
For the same efficiency, an aluminum radiator should have 2.5x the thickness as an equivalent copper radiator has.
= Costs for copper and aluminum tubes differ therefore little.
+ Brass knees + tin solder, cost less than the argon welding of aluminum.
- The welding of aluminum causes :
extra transport costs of the completed loop to the antenna site,
impossible moving through housing.
+ Copper tubing can be cheaply soldered yourselves for free, using tin solder.
+ Separate 2.5m long copper tubes can be costless transported in you car :
and easily moved through buildings.
= Copper and aluminum must both be painted as bare aluminum oxidizes too.
+ The thinner copper tubing is less obvious than bigger aluminum tubing.
Copper tubing is much cheaper to use and easier to construct.