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Filter 247 (247-W)

Filter 247 ; General Radio (ID = 1056429) mod-pre26
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Filter 247 ; General Radio (ID = 1056429) mod-pre26
General Radio: Filter 247 [mod-pre26] ID = 1056429 867x933
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For model Filter 247 (247-W), General Radio Company; Cambridge (MA):
Ad in Radio News, Feb.1925, p.1508
Country:  United States of America (USA)
Manufacturer / Brand:  General Radio Company; Cambridge (MA)
alternative name
Year: 1925 Category: Radio module pre 1926 (not a part, not a key)
Main principle RF-Circuit or wave trap (separate, can also be an antenna with amp.)
Wave bands Broadcast only (MW).
Power type and voltage No Power needed
Loudspeaker - - No sound reproduction output.
Power out
from Model: Filter 247 - General Radio Company;
Material Various materials
Dimensions (WHD) 8 x 6 x 4 inch / 203 x 152 x 102 mm
Notes Condenser in metal can, coil body made of Bakelite. The Variable Condenser is marked "Wavemeter". Type 247-W Filter to tune out Interference from unwanted stations. The wavelength is given as 150 to 500 metres, the max. capecity of the variable is 500 µµF.
Not to be confused with the almost similar Type 274-W, wich covers a range of 200 to 600 metres.
Price in first year of sale 10.00 $
Mentioned in Radio News (January 1925 (p. 1318); February 1925 ( p. 1508))

Model page created by Konrad Birkner † 12.08.2014. See "Data change" for further contributors.

All listed radios etc. from General Radio Company; Cambridge (MA)
Here you find 216 models, 197 with images and 84 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.