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Modulation level indicator 678

Modulation level indicator 678; Eddystone, (ID = 2303656) Amateur-D
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Modulation level indicator 678; Eddystone, (ID = 2303656) Amateur-D
Eddystone,: Modulation level indicator 678 [Amateur-D] ID = 2303656 849x1500
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For model Modulation level indicator 678, Eddystone, Birmingham:
Manufacturer's documentation
Country:  Great Britain (UK)
Manufacturer / Brand:  Eddystone, Birmingham
alternative name
Stratton & Co.Ltd.; Birmingham
Year: 1948–1955 ? Category: Amateur Equipment (Other, but not Key)
Main principle Crystal or Solid State Detector
Wave bands Wave Bands given in the notes.
Power type and voltage No Power needed
Power out
from Model: Modulation level indicator 678 - Eddystone, Birmingham
Material Metal case

Housed in a ripple black diecast case similar to the better-known 669 S meter, the Eddystone 678 modulation meter is a passive field strength meter using a pair of germanium diodes and a 200 microamp fsd meter. A small pickup aerial screws into a socket on top of the case, and one of six coils plugs into the rear. The six coils supplied cover the 10, 15, 20, 40, 80 and 160 metre amateur bands.

To measure amplitude modulation depth, the RF pickup is adjusted until the meter reading coincides with a special mark on the scale. On switching over, modulation percentage can be read off the calibrated scale directly. A jack is also provided at the rear for plugging in monitor headphones.

Price in first year of sale 8.75 GBP

Model page created by Bruce Taylor. See "Data change" for further contributors.

All listed radios etc. from Eddystone, Birmingham
Here you find 235 models, 88 with images and 34 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.