This antique radio calibration curve chart, dated September 10, 1925, was used for tuning and frequency calibration in early tube radios. It includes a frequency-to-wavelength conversion graph for the right-hand "Station Selector" dial and features a serial number (85451).

The chart was likely used in Atwater Kent, RCA Radiola, or other early TRF radios, making it a rare piece of radio history. It would be ideal for collectors, restorers, or vintage electronics enthusiasts.

Item Specifics:

• Brand: Unknown (Possibly Atwater Kent, RCA, or Early TRF Radio)
• Material: Aged Paperboard
• Type: Calibration Curve Chart
• Era: 1920s Vintage
• Date: September 10, 1925

Estimated Item Dimensions & Weight:

• Size: Approx. 5.5" x 6"
• Weight: Lightweight

Condition:
Pre-owned with signs of age-related wear, small tears, and hole-punches. Some discoloration and edge damage, but text and graph remain clear. See photos for exact condition.

Additional Details:
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The item in the photos is the exact item you will receive. If any details in the description seem different from the pictures, please trust the photos as the most accurate representation of the item.

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Keywords:
Antique radio calibration chart, vintage tuning graph, 1925 tube radio tuning, Atwater Kent calibration, RCA Radiola, early TRF radio part, antique radio restoration, frequency conversion chart, vintage radio paperwork