Description
For sale is a rare, vintage Hammarlund Air Padding Condenser, left behind in the electronics components inventory of my late father, who was a radio and TV serviceman for much of his life, and was an active HAM radio operator for over 70 years. My husband, who understands electronics much more than I do, did a bit of research on this item, and here is some of what he found: DESCRIPTION: What makes this component so RARE? The mold for the ceramic base is NOT engraved with the name Hammarlund, as it appears on most surviving examples of this vintage artifact. All other features, including the ink-stamped APC-100 Hammarlund part number, suggest that this vintage, APC-100 air padding condenser may be a very early, collectible representative of the famous, mid-line variable condenser which Hammarlund developed in 1925. I cant find another APC-100 like this. The former owner of this artifact was a HAM Radio Amateur, who obtained his license in 1937, and who is, sadly, now a silent key. This air padding condenser was designed to deliver 100 picoferads capacity. It features dual functionality for rotor adjustment, with a screwdriver slot and a hexnut. These components are highly prized by Radio Amateurs, and are used in receivers and transmitters to calibrate internal L-C circuits, such as band set, band spread, final plate tuning, antenna loading, etc. INVENTORY CLASS: This item has solder on the rotor and stator terminals. It is pre-owned, with an unknown history. MANUFACTURER: This appears to be an early Hammarlund. Hammarlund Manufacturing Company, Inc., New York, New York, U.S.A. PART NUMBER: APC-100 (ink-stamped on the base) CONSTRUCTION: Plate Geometry: half-round Plate Radius: about 27/64 Plate Spacing: about 0.015 Stator Plates: 14 total Rotor Plates: 13 total Stator Terminals: Two (2) tinned, wire-wrap terminals Rotor Terminal: One tinned, solder tab terminal (about 1/8 wide by about 3/4 long) Rotor Adjustment: Dual functionality: slotted shaft for screwdriver, or 1/4 hex for nutdriver or wrench Base Dimensions: About 15/16 wide, and about 1-3/16 high Maximum Depth from Panel: About 1-9/16. CAPACITANCE: Minimum: About 7.3 picofarads Maximum: About 109 picofarads MOUNTING: Panel mounting on about 21/32 centers; mounting studs are tapped for #4-36 mounting screws. Two #4-36 round-head mounting screws, with 9/16 thread are being furnished. (Depending on your panel size, these screws may be too long and may need to be cut to the desired length.) CONDITION: As is, as found, and as photographed, with typical age-related and environmental, handling and storage effects (see photos). Seller has no specific knowledge of the condensers actual history or prior applications, but it appears to have had little prior usage. WHO WANTS THIS? Hammarlund collectors, collectors of antique and vintage radio components, HAM radio amateurs, experimenters, anyone wanting a treasure from radio history! Well, that a lot! But, what a cool artifact! I hope that is one that you would love to have!! Thanks for looking here! (misc 19)
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