Make
Raytheon
Model
RK5721
Raytheon RK5721
The Raytheon RK5721 is a vintage reflex klystron microwave tube, primarily designed for use in radar and SHF/EHF applications (frequencies above 3 GHz). It features a special tube base and is noted for its external cavity design, allowing tunability for X-band oscillators around the 1950s era. These tubes were produced by Raytheon (now part of RTX Corporation) and are often found as new old stock (NOS) in original packaging, with collectors valuing their brass construction and factory-original dimpled glass envelopes for steampunk or RF amateur radio projects.
Key Specifications (from available data sheets)
| Parameter | Details |
|---|---|
| Type | Reflex Klystron (microwave oscillator) |
| Frequency Range | SHF/EHF (>3 GHz, tunable X-band) |
| Envelope | Glass with dimples (factory-original) |
| Filament Continuity | Typically good in tested NOS units |
| Applications | Radar systems, microwave transmitters |
| Era | Mid-20th century (e.g., 1950s references) |
Detailed data sheets, including electrical characteristics and tuning curves, are available in resources like the Raytheon Special Purpose Tube manual. These tubes occasionally appear for sale on collector sites, priced around $20–$50 depending on condition.