The end-fed half-wave (EFHW) antenna is a great choice for mobile operation.
The end-fed half-wave (EFHW) antenna is about the same size as a dipole, but the connection is on the end instead of in the middle like with a dipole. This generally makes portable operation easier as you only need one or two mounting supports instead of three. An EFHW is only good for one frequency, but this can be overcome by making the antenna “linked” - wire sections you add or remove depending on the total length you need.
The one downside of this antenna is that it requires a matching transformer, but you build that into the antenna.
Note: Length is in feet and frequency is in MHz.
The matching unit (an UnUn) is made by winding a 49:1 transformer on a FT140-43 or FT240-43 toroid core. A 49:1 transformer can be created using a 2:14 or 3:21 ratio. I’ve also seen references to 2:16 working on 10/12m, 3:24 for 15-80m and 4:32 for 160m bands (1:64 transformers). Apply a 100pF HV ceramic capacitor across the primary of the matching unit.
