In a VHF superheterodyne receiver, which stage must be designed to produce very little noise?

In any receiver system, the overall noise performance (or noise figure) is dominated by the very first active stage in the signal path. In a VHF superheterodyne receiver, this first stage is the RF amplifier. If the RF amplifier generates internal electrical noise, that noise gets combined with the weak incoming signal and is amplified by every subsequent stage (like the IF amplifier and audio stages). Once noise is introduced at the very beginning, it cannot be removed, which will mask faint signals. While stages like the IF amplifier, product detector, and limiter also need to be reasonably well-designed, the signal has already been significantly amplified by the time it reaches them. Therefore, their internal noise contributions are far less critical than that of the initial RF amplifier.