Summary of Contents for Datawell 45100
- Page 1 Datawell Waverider Receiver Manual RX-D type 2 from serial no.: 45100 Service & Sales Voltastraat 3 October 14, 2015 1704 RP Heerhugowaard The Netherlands +31 72 534 5298 +31 72 572 6406 www.datawell.nl...
- Page 2 Check if mains supply matches with the specifications of the device.
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Page 3: Table Of Contents
Contents 1 Introduction ....................5 2 Front- and back-panel layout ............... 7 3 Installation ..................... 9 3.1 Power supply .................... 9 3.2 Receiving antenna ................... 9 3.3 Connecting the serial output to a PC ............10 3.4 Grounding ....................10 3.5 Lightning protection ................ -
Page 5: Introduction
1 Introduction The RX-D type 2 (RX-D2) is a HF link receiver that can receive all current Datawell Waverider buoys with a standard (FSK) HF link transmitter. The RX-D2 is tuned to the reception frequency using exchangeable receiving crystals. The RX- D2 is connected to a PC running W@ves21 using RS232. -
Page 7: Front- And Back-Panel Layout
2 Front- and back-panel layout The front panel contains the LCD and the speaker / test button. The back panel contains the following connectors: Socket for mains supply with fuses. Audio out for beat-note monitoring. Female 9-pin RS232 connector. ... -
Page 9: Installation
3 Installation This chapter describes how to install the RX-D2. To function correctly, an RX-D2 needs at least the following: Power supply. Receiving antenna. Connection to a PC using the serial port. The following paragraphs will discuss these connections as well as grounding and lightning protection considerations. -
Page 10: Connecting The Serial Output To A Pc
Using an antenna splitter For connecting multiple receivers to a single antenna, the Datawell Antenna Splitter can be used. This device is optimized for the buoy reception frequencies and signal levels. With the Datawell Antenna Splitter up to six receivers can be used with a single antenna. -
Page 11: Lightning Protection
3.5 Lightning protection For effective protection against lightning strike it is advisable to connect the antenna supporting structure to a ground electrode that is suitable for lightning protection. In the case that the building or adjoining buildings and/or mast on which the antenna is installed is already lightning protected it is sufficient to connect the antenna supporting structure to this grounding net. -
Page 13: Operation
4 Operation This chapter describes the general operation of the RX-D2. For a description of the normal operation of the RX-D2, refer to paragraph 4.1. When the reception frequency needs to be changed, refer to paragraph 4.3. 4.1 Receiving data When the receiver is in normal operating mode, the current status of the receiver is shown on the display (see figure 4.1). -
Page 14: Gps Position
4.1.1 GPS position When the buoy being received is equipped with a GPS module, the GPS position of the buoy is shown on the display. The GPS position message is “rotated” with the heave message according to the scheme shown in figure 4.2. Figure 4.2. -
Page 15: Realignment Procedure
The realignment procedure aligns the receiver to the buoy being received. The recommended procedure is to send the RX-D2 back to Datawell when the receiver needs to be realigned. If this is not possible, the realignment procedure can be carried out locally by following the procedure below. -
Page 16: Changing The Reception Frequency
6). When the frequency of the receiver needs to be changed, the recommended procedure is to send the RX-D2 back to Datawell for exchanging of the crystal and subsequent realignment of the receiver. Please contact Datawell sales for more information. -
Page 17: Troubleshooting
5 Troubleshooting This section of the manual describes the steps you should take when you believe the Datawell RX-D2 is operating improperly. The results of these simple investigative procedures may help you avoid the down-time and inconvenience of repair service. It is assumed that the installation worked before the trouble started, in other words: installation has been done in a correct way according to chapter 3. -
Page 18: Data Interface
means that the signal-to-noise or interference ratio is troublesome. Push the speaker button on the right side of the display and listen to the signal. Normally only the beat-note (characteristic warbling sound) of the buoy signal accompanied by more or less noise should be audible. If nothing is heard, check antenna and/or cabling. -
Page 19: Specifications
6 Specifications RF front-end Frequency range: 25.5 ... 35.5 MHz (standard) or 35.0 … 45.0 MHz (option). Crystal selected reception frequency. Usable sensitivity: -116 dBm (0.5 μV). Dynamic range: >60 dB. In practice this means that a signal differing 5 kHz or more with the buoy signal will do no harm at signal levels below -50 dBm. -
Page 21: Contact Information
7 Contact information Sales Voltastraat 3 1704 P Heerhugowaard The Netherlands Tel: +31 72 534 5298 Fax: +31 72 572 6406 E-mail: sales@datawell.nl Service Voltastraat 3 1704 P Heerhugowaard The Netherlands Tel: +31 72 571 8219 Fax: +31 72 571 2950 E-mail: servdept@datawell.nl... -
Page 22: Appendix A: Buoy Hf Data Link And Range
Appendix A: Buoy HF data link and range The Waverider- and Directional Waverider Buoys send their data to the shore using a HF data link. This data link system can be represented by the functional block diagram shown in figure A.1, and consists of a buoy with its transmitter and transmit antenna, a channel –the atmosphere through which the buoy signals are wirelessly transmitted- and a receiver, namely the RX-D2 and its receiving antenna. - Page 23 Possible error sources and solutions: Error: The transmitter does not work any more. Solution: check batteries and replace batteries when they are dead, if the batteries are all right: contact our service department. Error: The crystal frequency has changed too much. This can happen because of ageing, or when the buoy has been handled too rough, e.g.
- Page 24 A.3 Communication channel The communication channel between the buoy and its receiver is the atmosphere through which the buoy’s RF signal propagates wirelessly. This is the least predictable part of the buoy communication link and determines for a large part the quality of the received signal. Phenomena which play a role in the communication channel between the buoy and its receiver are distance, noise, interference, propagation, wave height and the existence of other transmitters.
- Page 25 A.3.2 Noise Natural noise is always present and has many appearances. Since most of the natural noise generated in our atmosphere due to a phenomenon called “weather”, the noise depends on the season, the part of the day and the propagation characteristics (see below). An increase of natural noise will degrade the signal to noise ratio and therefore will decrease the link range.
- Page 26 enough to overdrive the receivers input stages. Identifying an interferer can be done with a commercial HF receiver for the 20-40 MHz band or with specialized equipment such as a spectrum analyzer. Fortunately interferers in general come from one direction only –usually away from the shore- and it is often possible to use a directional antenna directed at sea so that it more sensitive in the buoy direction and less sensitive in the direction of the interference source, usually located in the residential and business areas closest to the buoy receiving site.
- Page 27 Or both. Not coincidentally the height of the HF antenna on the buoy! At the Datawell laboratory in Haarlem we are able to receive buoys from Petten errorless at a low H but at an H of greater than 4 meter receiving acceptable data becomes impossible! The distance from Haarlem to Petten is 50 km and for the largest part over land, thus a very unfavorable condition.
- Page 28 At Datawell we developed a prediction tool for the case of one Datawell MKIII buoy interfering with an other Datawell MKIII buoy over direct sea paths. Datawell might able to help you with this tool when you are in trouble because of two MKIII buoys interfering with each other on the same frequency.
- Page 29 Technical details: A vertically polarized quarter wavelength whip with groundplane and with a gain of 2 dBi and an impedance of 50 Ω is normally used as a receiving antenna for the RX-D2. This is an omni directional type. Sometimes a directional antenna is used in the case of a too little link margin or in the case of interferers (see above).
- Page 30 Example 2: a “maximum setup” for 10 km mainly over fresh water ice with other obstacles will have an approximate loss of: (transmit antenna, see A.2) (distance over fresh water ice, see A3.1) (max. wave height 8 meters, see A.3.5) (some obstacles) + 10 (normal antenna height of 20 meters)
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Page 31: Appendix B: Output Message Format
Appendix B: Output message format The RX-D2 processes the incoming data by blocks of 64 bits. These blocks are called vectors. The buoy also sends its data in 64 bit vectors and protects each vector by a BCH (63, 51) error correcting code. -
Page 32: Appendix C: Warec Compatibility Considerations
DATA ACQUISITION SOFTWARE MUST BE ABLE TO DEAL WITH THE UNINTERRUPTED STREAM OF HEXADECIMAL BUOY MESSAGES. Datawell provides a software program named W@ves21 (for Windows95 and later) that performs the data filtering itself and can hence communicate with both WAREC and RX-D2. -
Page 33: Appendix D: Abbreviations
Appendix D: Abbreviations Alternating Current. Bose, Chaudhuri, Hochquenghem error correction code. deciBell. deciBell referenced to an isotropic antenna. deciBell referenced to a power level of 1 mW. Direct Current. Direct Digital Synthesizer. Digital Signal Processor. Instantaneous Frequency Deviation. Internet Protocol Global Positioning System. -
Page 34: Appendix E: Receiving Antennas
Appendix E: Receiving antennas E.1: Standard groundplane antenna Figure E1: Standard groundplane antenna. - Page 35 Adjust the antenna L1 and L2 lengths to the transmit frequency of the buoy. Figure E2: Standard groundplane antenna (continued).
- Page 36 E.2 Directional Antenna 25 - 45 MHz Figure E3: Directional quarter wave antenna.
- Page 37 Using the directional antenna for the Reception of Waveriders over longer distances. 1. The received signal strength when the buoy is over the horizon decreases fast with increasing distance. To receive a buoy at 75 km distance with the same signal strength as at 50 Km distance 10 times the transmitting power will be needed.