For the lower bands I am using a 40/80 m trap dipole. In order to become qrv on 30 m, I added a radiation coupled lambda/2 element for 30 m, using 10 cm spreader. After cutting the additional wire to the right length, the resonance on 30 m is exactly at 10.1 MHz. The additional element has no influence on the resonance for 40 and 80 m, but the impedance on 30 m is with 150 Ohm significant higher than 50 Ohm.
![VSWR_30m](https://klsin.bpmsg.com/wordpress/wp-content/uploads/2018/02/trapdipole-30.bmp)
![40m_VSWR](https://klsin.bpmsg.com/wordpress/wp-content/uploads/2018/02/trapdipole-40.bmp)
![80m_VSWR](https://klsin.bpmsg.com/wordpress/wp-content/uploads/2018/02/trapdipole-80.bmp)