antenna – Page 2 – Experimental Engineering

Here is a phone from the mid 90s, the Ericsson GA628. Here visible is the front of the unit with keypad, & single line monochrome LCD for number display.

Here the battery is removed from the phone, showing the SIM card socket. At the top under the antenna stub is the socket for an external antenna.

Here the front is removed from the phone, PCB on left, rear of keypad on right. Microphone is at bottom of keypad, with speaker at the top. Top right of the PCB is the ringer buzzer, left is shield for RF amplifier.

Here is the back of the main PCB, RF sections on left & centre. Processing & memory on right.

This phone had a Ni-Mh battery, before Li-Ion batteries were introduced.

The LCD from the front of the phone is shown here. A simple dot matrix single line unit.

This is the Current Cost CC128 Real Time Power Meter. Shown here is the display unit, British Gas issued these free to some customers.
This unit measures current power draw in Watts, cost of power currently being used (requires unit price to be set), overall kWh usage over the past 1, 7 or 30 days & power trends during the day, night & evening. Also displays current time & current room temperature.

Here the front panel of the display has been un-clipped. At the bottom are the RJ-45 serial port & power connections.
This unit uses a PIC micro-controller as it’s CPU (PIC18F85J90) Just above & left of the CPU is the 433MHz SPD radio receiver module. The chips on the right of the CPU are a 25LC128 SPI serial EEPROM for data storage & a 74HC4060 14 stage binary counter, to which is connected the 32kHz clock crystal. The red wire around the top of the display is the antenna for the radio receiver.

For more info on the CC128 in general, the serial port & software for computer data logging, see this link
See this link for Current Cost’s list of software

Closeup of the ICs on the mainboard.

Here we have the transmitter unit, with Current Transformer (CT). The red clamp fits around one of the electric meter tails & read the current going to the various circuits. This unit is powered by 2x D cells, rated at a life of 7 years.

The PCB inside the transmitter. Again very minimal design, unknown controller IC, 433MHz radio transmitter on right hand side with wire antenna. Two barrel connectors on left hand side of board allow connection of up to two more CT clamps for measurement of 3-phase power. Centre of board is unmarked header. (ICSP?)

CT unit. Inside is a coil of wire & an iron core which surrounds the cable to be measured.

PIC18F85J90

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Ericsson GA628

Current Cost ‘Envi’ CC128 Power Meter