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Bud OLS-20, 20 Meter 50 Watt Oscillator and Buffer Coils Excellent Condition in Box #1

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OLS-20
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Bud OLS-20, 20 Meter 50 Watt Oscillator and Buffer Coils Excellent Condition in Box #1

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The Bud OLS Series refers to a vintage line of plug-in oscillator and buffer coils manufactured by Bud Radio Inc. (not Barker & Williamson/B&W, though often confused in ham circles due to similar era plug-in coil designs and overlapping use in amateur radio gear). These were popular mid-20th century (1940s–1950s) components for low-to-medium power HF transmitters, specifically designed for oscillator (e.g., crystal-controlled or VFO stages) and buffer (isolation/amplification) circuits, with a rated power handling of 50 watts input (typical for Type "B" low-power stages in era catalogs, suitable for CW or modulated setups without excessive dissipation).Bud (Bud Radio) produced these as part of their O-series plug-in inductors, often with ceramic bases, banana plugs for socket mounting, air-wound tinned copper coils, and an adjustable center link (the "S" in OLS likely denotes "Swinging" or "Adjustable Center Link" type, allowing variable coupling for loading/matching). They were compact, high-Q designs for band-switching in homebrew or commercial low-power rigs.Known Models in the OLS SeriesFrom vintage listings (e.g., eBay, RF Parts, old catalogs like Walter Ashe 1955), the series covers standard amateur HF bands with the band in meters suffixed:
  • OLS-80 — For 80-meter band (3.5–4.0 MHz). Adjustable center link; 50W rating.
  • OLS-40 — For 40-meter band (7.0–7.3 MHz). Common example; often seen with variable center link.
  • OLS-20 — For 20-meter band (14 MHz). Less common but documented.
  • Other probable variants: OLS-160 (160m, rarer), OLS-10/15 (higher bands, though often used OEL/OCL types instead).
Related Bud series include:
  • OEL — End-linked (fixed link at end).
  • OCL — Center-linked (fixed center link).
  • OES — Possibly end/swinging variants.
  • ONS — Band-switch assemblies (e.g., ONS-1 for 10-80m multi-band low-power use).
These were cross-compatible in many setups with B&W's Junior/HDVL plug-ins or similar (e.g., in transmitters using 5-prong or banana socket forms).General Information
  • Construction: Air-core, tinned copper wire on ceramic form/base with banana plugs. Includes main winding (often center-tapped) and adjustable center link for coupling to antenna/grid circuits (impedance matching, loading control).
  • Purpose: Optimized for oscillator/buffer-doubler stages in multi-band transmitters (e.g., crystal osc to buffer to final amp). High Q for efficiency; plug-in for easy band changes.
  • Power Handling: 50 watts (conservative rating for oscillator/buffer use
 
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