نمایشگرهای بزرگ 4985 شامل یک ماتریس 16 در 16 دو خط 42 میلیمتری و یا یک خط 84 میلی متری هستند. آنها نمایش مقادیری مانند زمان بسیار دقیق و تاریخ را بر عهده دارند
The basic version of the large display 4985 consists of a matrix measuring 16x64 LED. Two lines of 42mm or one line of 84mm alphanumeric characters can be displayed on this matrix.
The device can operate as a large display for values such as grid time, difference time and mains frequency which can be transferred from hopf System 7001(RC) with a board 7515(RC).
Different display and decoding programs are integrated in the large display 4985.
The large display is equipped with a highly accurate quartz clock which can be synchronized with a DCF77 signal. The DCF77 signal can be supplied to the BNC connector via an antenna or as a pulse to the respective inputs. The large display generates a DCF77 pulse and thus synchronizes further devices.
Time and date can be displayed in different formats.
Housing
The large display is set up in a black lacquered aluminium housing for wall installation.
The front page is of red and of coated acrylic glass and fixed into guiding rails of the housing.
For installation and configuration of the large display the right side panel of the housing and the front pane should be pulled to the right. The side panel of housing is mounted into guiding rails with spring locks.
Mechanical structure of the antenna
The antenna is housed in a round weatherproof plastic casing. The casing cover is arched to prevent any rain water, snow or other impurities from settling on the antenna.
The mechanical construction consists of sturdy, anodized aluminium or aluminium die-casting and is designed to resist high winds.
The plastic housing can be installed horizontally as well as vertically to the mechanical parts, allowing both wall and flat-roof installation of the antenna. The antenna cable can be fed either through the base or through a slot on the side of the mounting flange.
Electrical structure of the antenna
As the antenna is non-directional, reception cannot be improved by mechanical shaping as, for example, with parabolic antennas. Therefore the signal strength at the antenna input is about 1 x 10-16 Watts and already below the generally permitted noise level.
An extremely low-noise pre-amplifier is placed behind the antenna in order to feed the signals to the electronics via an antenna cable. The antenna cable also supplies the voltage to the pre-amplifier.
When outdoor antennas are used high interference voltage or current pulses may occur in the antenna cable during thunderstorms. This may result in damaging or destroying not only the directly connected radio-controlled clock system but also any other devices connected.
To avoid severe damage and damage-related costs an indirect lightning protection should be installed between the outdoor antenna and the circuit board of the radio-controlled clock.
This is why the hopf lightning strategy is made up of a combination of rough and fine protection.
Rough Lightning Protection
The double-chamber gas arrestor, located in the lightning protection, has a dynamic operating voltage of < 700 V and conducts voltage, when ignited, out of the cable to the earth potential.
Fine protection (in the hopf GPS receiver board)
Fast absorber diodes with a response time of < 1 nsec. and an absorber power of 600 W at the input of the GPS receiver board keep the potential differences between antenna core and zero at a constant approximate ± 6 V until ignition of the double-chamber gas arrestor.
Because of the high frequency and the signals below the permitted noise level, the elements must be set up in strip-line sequence. This combination also guarantees the potential separation of the antenna circuit to other electronics in conditions without interference.
If no further devices (eg. power splitter) are installed between lightning protection and electronic with fine protection, for safety reasons a maximum cable length must not be exceeded (please have a look at the drawings in the technical manual which can be found in the tab 'Download').
Passive GPS 2x Power Splitter
If only one GPS antenna can be installed (due to structural or other reasons), it is however possible to operate two GPS receivers with one common GPS antenna by using the passive GPS antenna splitter 4443.
Voltage for Power Splitter 4443 is supplied internally by the system via the GPS antenna cable of the connected hopf GPS receivers. No external power supply is needed to operate the application.
The GPS antenna splitter 4443 can also be used together with a third-party device if at least one of the connected GPS receivers provides suitable supply voltage via the antenna cable and if all connected components are working in accordance with the original GPS L1 antenna signal.
The power splitter is built in a HF-proof housing with an insulated base plate. The unit can therefore be easily screwed to the wall near the GPS receivers. The GPS antenna is connected to the BNC-connector called 'Antenna In'. On the opposite side of the housing two signal outputs to the GPS receivers are located.
If only one GPS antenna for operating several GPS receivers can be installed (due to structural or other reasons), it is however possible to operate up to 8 GPS receivers with one common GPS antenna by using the active GPS antenna splitter 4449. This solution is often used in the context of superstructures for conducting device tests in laboratories or testing stations.
The active GPS antenna splitter 4449 contains 8 outputs and a signal amplification.
The GPS power splitter 4449 is available in two versions:
FG4449G00
Active GPS power splitter für GPS L1 antenna signal with 8 outputs and signal amplification. System-internal power supply via GPS antenna cable
The necessary voltage for operating the unit is supplied system-internally via the GPS antenna cable of the connected hopf GPS receivers plugged in the master output. No external power supply is needed to operate the unit.
The application's 8 signal outputs are subdivided in 2 output groups (output A and output B) with 4 outputs each. Each output group has one master output and three slave outputs.
The supply voltage for the two output groups is respectively fed by the hopf GPS receiver which is connected to the master output of the output group. Without system-internally supplied voltage via the master output of an output group no signal output via this group takes place.
FG4449G01
Active GPS power splitter for GPS L1 antenna signal with 8 outputs and signal amplification. Power supply via external voltage source
An external voltage source (18-60V DC, Imax = 300mA) for feeding the antenna splitter is necessary. Connection of the 8 outputs to the application can be done in any sequence.
A system-internal power supply via the connected hopf GPS receivers is not necessary.
The active GPS antenna splitter 4449 is optionally available with a modification for connecting GPS receivers with antenna circuit monitoring. Due to this modification a current of approximately 13 mA per each output is achieved for connection of the hopf GPS receivers.
The line amplifier is integrated into an HF proof housing with a base plate. It is therefore easy to fix the device to the wall.
The 6849 line amplifier is looped into the antenna cable. The voltage supply of the line amplifier is provided via the antenna cable by the BNC connector of the hopf GPS system.
The GPS antenna cable from the antenna is connected to the BNC connector 'ANTENNA'. The signal is supplied to the connected hopf GPS system by the BNC connector 'RECEIVER'.
To avoid destruction caused by overloading ensure that the line amplifier is not earthed.
The integrated fine protection of the line amplifier enables installation before the lightning protection without any risk of destroying the line amplifier through overloading.
If several DCF77-clocks are wanted in the building the 4x antenna amplifier with potential separation can be used. The device is structured like the antenna amplifier FG444400, but without indirect lightning protection.
The housing contains the mains unit and several amplifier modules.
The signal is fed via a pre-amplifier to 4 potential free output steps and put out via insulated BNC-connectors on the wider side of the housing.