Re: antenna connection
You should be careful so the output of the amplifier is terminated on correct impedance, and use coax cable and connectors.
If you have loose wires in RF, and the whip antenna is near, also connected with common wires, the amplifier may oscillate, because the antenna will couple back the amplified signal, resulting in feedback and oscillations. This is true especially if the amplifier has a high gain and uses UHF/SHF transistors.
A groundplane antenna is more correct.