Radio Condenser Co. Dual 2-Gang Variable Capacitor 4-Section 8-90pF w/ Trimmers

Radio Condenser Co. Dual 2-Gang Variable Capacitor 4-Section 8-90pF w/ Trimmers

This Radio Condenser Co. dual 2-gang variable capacitor is a precision air-variable unit with four sections and balance trimmers, built for high-Q RF tuning applications. It features silver-plated rotor and stator plates, a ceramic shaft, ceramic insulators, and ball bearing end supports — a construction approach associated with stable, low-loss performance in demanding RF circuits.

Specifications & What's Included

• Configuration: Dual 2-gang (4 sections total)
• Capacitance range per section: 8–90 pF
• Balance trimmer per section: 0–5 pF (subtractive — half-trimmer wired across each section)
• Two sections with isolated rotor connection: 8–90 pF each
• Two sections in series via floating rotor: 10–49 pF total
• Contact plating: Silver-plated rotor and stator plates
• Shaft material: Ceramic
• Insulators: Ceramic
• Bearing support: Ball bearings at shaft ends
• Mounting: Integral mounting brackets

Applications

Multi-gang air variable capacitors like this Radio Condenser Co. unit are used in RF tuning circuits where precise, low-loss capacitance adjustment is needed. They are a standard component in amateur radio transmitters, receivers, and antenna tuners — particularly in designs requiring dual or ganged tuning sections to track across a band simultaneously. The isolated-rotor and floating-rotor section arrangement makes this unit well suited for balanced or differential tank circuits, transmatch designs, and other applications where rotor isolation matters. The ceramic shaft and insulators keep stray capacitance and RF losses low, which is especially important at higher frequencies. Vintage units like this one — from the mid-20th century era of American RF component manufacturing — remain actively sought by amateur radio builders, vintage radio restorers, and homebrew transmitter constructors who value the robust mechanical construction and silver-plated plate surfaces that newer commodity capacitors rarely match.