Article
TX Check for GSM/DECT Phones
A fieldstrength meter is all you need for a quick go/non-go check on the transmitter section (TX) in a GSM phone (900 MHz or 1800 MHz), a DECT phone (1900 MHz), or a base station.The antenna used here is a half-wave dipole designed for a wavelength of 32 cm (900 MHz band) or 16 cm (1800 MHz band). Theoretically, the dipole ‘arms’ have a length of 80 mm (900 MHz) or 40 mm (1800 MHz). However, because the conductors (1) have a finite thickness, (2) are not suspended in free space but etched on a printed circuit board and (3) are close to other objects, the actual length is not given by theory.
Materials
Gerber file
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PCB
Component list
Capacitors:
C1,C2 = 1nF ceramic
Semiconductors:
D1 = AA117, AA119
Inductors:
L1,L2 = choke, 10 turns, 0.5mm ECW, internal diameter 5mm
C1,C2 = 1nF ceramic
Semiconductors:
D1 = AA117, AA119
Inductors:
L1,L2 = choke, 10 turns, 0.5mm ECW, internal diameter 5mm
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