The Model 3109 Biconical Antenna uses a modified Guanella balun for impedance transformation and matching and provides a broad frequency range. Because it is constructed with heavier materials, it has a maximum continuous input power up to 1 kW, with an up to 2 kW peak power handling capability.

While it typically has a high VSWR at frequencies below 70 MHz, the 3109 is still capable of generating a high field strength with acceptable input power in this region of the band. It is ideal for IEC 61000-4-3 testing.

Optional extended elements can be added to the 3109 to make it twice as long and enable users to generate high fields at low frequencies with less than 25% of the power usually required.