At the moment I've got an 80/40/30/20 segment dipole hoisted up. That could change in the next few minutes. I'm just wired that way. (see what I did there...)
A better way to have phrased the question is: "How many HF bands are you able to operate effectively on?" A ladderline-fed 160m or 80m dipole at 150 feet would probably do very well on all of them. A dummy load would as well - but not "effectively" Dave W7UUU
One antenna serves all HF: 250-foot long doublet fed with open wire with Twin-T differential matching network (homebrew) in the shack. Each side of the Twin-T matching network has a robust quadfilar common-mode choke. I have an HP VNA to measure the CM chokes. I went quadfilar to reduce losses. The chokes function in a bifilar configuration. Windings 1 and 3 and connected together while windings 2 and 4 and connected together. This reduces losses as well as reduces the characteristic impedance of each choke as a length of transmission line. The Davis RF highly flexible insulated 'antenna wire' makes wonderful conductors for winding these CM chokes. They're wound on dual 4-inch OD 43 material. Dave - WØLEV
As my antenna is on poles setup with pulleys, I have different dipoles cut for each band and I change it out based on what I want to operate. Doesn't take hardly any time at all to switch out for one band to the next. Maybe one day I'll try a multi-band.
80/160m: cage inverted vee, apex @ 70' AGL on 80m), driven against ground as a vertical on 160m (link). 40/15m: dipole @ 65' AGL. 20m: λ/2 vertical on the roof (link). 40/20/15/10m: Force12 C-4XL yagi @ 72' AGL (link) *. 10m: Cushcraft AR-10 λ/2 vertical above the yagi @ 83' AGL. 20/15/10m: Cushcraft A3S yagi @ 30' AGL (no longer used). * It also loads on 30, 17 & 12m w/ minimal trouble.
You should have also included uhf/vhf/hf. I have 70cm-160m capability. It's just that the 160m option sux. Matt