If you have a decent ground (such as ground plane made of sloping radials), why on earth (sic) are you using a vertical dipole as radiator. A vertical dipole is hard to support and have transmitter connections without harming the radiation patterns.
If you can make a decent ground plane system, use 1/4 or 5/8 wave monopoles for both the radiator as well as for the passive monopoles. In this way, the ground can work as mechanical support with only an insulator between the actual element and ground plane. The transmitter is connected across the insulator, while the loading resistor (30-37 ohms) are connected across each passive element insulator.