Total posts : 45366
The resonance for a quality dipole is rather sharp, enough so that within a typical amateur band it is a compromise to keep the tuning operable throughout the band. Broadcasters have an advantage in that they work on a fixed frequency and can optimally tune their antenna accordingly. On the ham bands a SWR of 1.5 : 1 is acceptable. At a local high power FM station here the transmitter shuts down at 1.15 : 1.
Consider using a vertical dipole. The nulls will be up and down rather than horizontal. The inverted V which I think you are using radiates a strong signal upward from horizontal which is great for ham use but will go over the heads of your potential audience. Maybe invert the inverted V?
Typically, an antenna tuner is used to make the transmitter see a proper load despite serious mismatch with the feed line and the antenna. Tuning the antenna with a variable cap or inductor as you mentioned makes sense and will work and is often done for transmit antennas. In the case of a dipole, it is much easier and lower loss to just cut it to the proper length and call it good.