Certain preparations should be carried out prior to installation:
1. Prior to commence operations, it is required to study ground plane documentation.
2. Laydown ground plane radials equally along the antenna array. Fasten radials on ground by using hooks (depending on ground characteristics and ground plane specification). Radials laying may vary depending on landscape and buildings surrounding antenna site.
3. Place the ground plane girth.
4. Cut МГ-10 cupper wire to 300 mm sections and untwist segments into wire harnesses.
Harnesses shall be used for winding crossing points between the ground plane radials and ground plane girth.
5. Crossing points between the ground plane radials and ground girth shall be cleaned from the oxides and then wrapped by two wire harnesses.
6. Solder wire harness winding with soldering alloy ПОС40 using acid-free method. Please note that welding of bimetal radials causes destruction of copper coating surface.
7. Connect ATU ground plane lead wire (from the ATU, installed in shelter) to the ground plane girth. Solder the connection point with soldering alloy ПОС40 by acid-free method. Please note that ground plane lead wire is connected to the site grounding system only by means of special jumper in ATU. It is recommended to lay the ground plane lead wire in plastic cable conduit inside the shelter.
The new version of firmware and feedback between NDB Station and ATU offers a number of useful options such as output power limitation, antenna current stabilization and automatic resistance matching.
It is important to note that NDB factory settings of these options have the following values:
- the output power limitation value threshold corresponds to the maximum output power of NDB
- antenna current stabilization option is set to value 3.8 A
- automatic resistance matching option is OFF
How to activate and monitor these options?
АThese options can be activated with help of PC, connected via Ethernet, or with help of menu system of the LCU control touch screen (available only on NDB equipped with touch screen).
Operation modes can be monitored with the help of integrated WEB server.
- indicator "AUTOMATCHING" displays state of the option of automatic resistance matching. When the option is on, the indicator is green. During searching of effective matching, the indicator becomes yellow. When the option is off, the indicator is grey.
This option actually eliminates the need to make seasonal changes in ATU, as well as to perform manual changes in matching transformer settings.
- indicator "ANTENNA CURRENT STABILIZATION" displays the actual state of antenna current stabilization option. Green color of indicator corresponds to the option switched-on state and antenna current conformity to the preset value. In case of antenna current value deviation from the preset value one, the indicator becomes yellow. When the option is off, the indicator is grey.
With help of this option, the transmitter is able to adjust automatically its output power to provide a constant antenna current, thereby maintaining constant field strength of the radiated signal.
Option of output power limitation may be useful in case, when the transmitted power limit value on site is set in accordance with sanitary standards.
New generation of equipment allows to perform control, monitoring and remote assistance via Ethernet. The remote assistance allows to involve R&D engineers for troubleshooting and carrying out of remote technical assistance, assistance in start-up and commissioning operations and detect critical states in operation of the equipment during routine use. Connection via Ethernet also allows to keep operational log on several independent computers.
By using the specialized software and access code, all options of the NDB are available from the connected computers. It should be noted, that the embedded WEB server makes the remote control and monitoring (on function level of RCU) possible without special software (access level is similar to RCU).
From the Technomarine side equipment support is maintained by using following hardware:
- two industrial computers
- two industrial Ethernet switch
- uninterruptible power supply
- backup communication channel (connection via Ethernet 3G/EDGE/GPRS routers or satellite communication terminal can be used). Information security is provided with help of firewall.
Since the device T220 is no longer in production and for the present moment there is no substitution for T220 ampermeter, we suggest the following ways of solution:
On NDBs with serial numbers of 88 and higher, there is socket for monitoring of emitted signal "RF check" in ATU. Using the signal from this socket and accepted oscillograph, it is possible to determine the current value in the antenna circuit.
On NDBs with serial numbers up to 87, there is no such socket in the ATU. In this case, to determine the antenna current value with use of oscillograph, it is required to modify ATU. The set for modification, including current transformer, front panel and detailed instruction on modification, can be ordered at our company. The modification is to be documented in accordance with the bulletin.