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Iskra Transmission, d.d.
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FAQ / SparkWave
What does it mean Ethernet and TCP/IP standards and protocol compatibility?
The equipment is compatible with Ethernet and TCP/IP standards for communication through IP stacks.

What is SparkWave antenna alignment procedure like?
Antenna must firstly be aligned to the main lobe of the radiation pattern and after that to the maximum of the receiving signal. For the reception of the (Rx) signal power level measurement IF AGC voltage of RF module is used. The accuracy of the Rx signal level measurement is ~2dB; the dynamic range is from -90 dBm to -30 dBm. An analog voltage (15 mV/dB) representing the Rx level for antenna alignment purpose is available for RF module.

In many cases "Radio Licence" is needed. How do I know whether it is needed or not?
There are some frequency bands left open for so called "Licence free" use. However, there are some limitations, such as disturbances and a large number of users. You should verify at your local agency, which has a power to issue the Licence, which frequency bands are disposable and on what terms. Sometimes, Radio Licence is needed also for imported equipment. Free radio channel (frequency) can be assigned as a concession, or for each project with the annual fee.

Why should I be bothered with the "Radio Licence"?
Radio Licence does mean some delay in implementation and additional costs, but it assures that no one will interfere with your radio connection. That is a must if you want to insure a connection with higher degree of availability.

Active Repeater is your specific product. In which cases should it be used?
It is meant for rural areas with no or bad infrastructure. Together with solar power supply (with batteries) it can be operated in areas with no infrastructure. Naturally, passive repeater can be used in such situation, but with many limitations (construction and alignment, distances, angles ...). Low consumption enables approximately 30 days of autonomy.

Can Active Repeater be used with other radios?
Basically it can. But, you should consult with our technical support team and give them more technical details and regulatory demands, in order to determine the right solution.

Are there any situations where the use of Active Repeater is not recommended?
Active Repeater should not be used in densely populated urban areas, with many radios working in in relatively small area and on similar frequencies. In that case, Active Repeater can be the cause of interferences if not projected properly.

How can you connect radio Ethernet modules transferring IP traffic over SparkWave radio?
There are more possibilities:
  • In case of protected configuration (1+1) Ethernet module EWM34 A1 and two SYM34 A2 modules are connected by four cables with SMB connectors.
  • Ethernet EWM34 A1 (A2) module is connected to SYM34 A2 only by two cables with SMB connector. Instead of SparkWave radio any other transmission media can be used.
  • Ethernet EYM34 A1 (A2) module is connected directly to RF part of SparkWave by coaxial cable.

What's the intermediate frequency between IDU and ODU?
Indoor unit (IDU) and outdoor unite (ODU) of SparkWave radio are connected by single IF cable. Tx frequency is 1489,5 MHz and Rx frequency is approximate 480 MHz.

Can Iskra Transmission supply a solution for connecting two buildings only 100 meters apart?
Yes, at 23 GHz, however, we would need an additional attenuator.
Yes, at 38 GHz with the smallest antennas (0.17 m).

What is the effective throughput of EWM34 and EYM34?
Effective throughput depends on frame length and comes close to channel capacity at long frames:

Fr. length Mbit/s
1518 33.92
1000 33.7
500 33.05
300 32.2
200 31.2
100 28.6
64 23

What is the functionality of your Ethernet ports? Do they work as a bridge, switch or as a router?
The ethernet ports work as a switch.

Is your radio channelized or unchannelized?
Our radio can transmit transparently all baseband signals according to ITU-T G.703 standard (4x2, 8, 16x2, 34Mbit/s) regardless of the ITU-T PDH hierarchical structure.

When did you develop the 1st radio?
Our company has 50 years experience in radio development. The first radio was developed in 1953.

Can SparkWave radio links be used for a CDMA network?
Our SparkWave is PTP (point-to-point) radio family. CDMA (code division multiple access) is one of the solutions of PTMP (point-to-multipoint) radio access system. SparkWave can be used for access spots connection of CDMA network.

What are the advantages of QAM modulation compared to QPSK?
QAM (quadrature amplitude modulation) abbreviation emphasizes linear transfer characteristic of the modulation of two orthogonal frequency carriers. The consequence is the possibility of base band pulse shaping instead of modulated signal frequency shaping. In case of QPSK, the transmitter spectrum must be shaped after modulation, which can cause problems due to very narrow band pass filters.

What digital and what analogue channels can be transmitted over service channels?
Digital service channels of overall transmission capacity 512 kbi/s are available for 8 and 34 Mbit/s transmission system. A digital service channel can be used for analogue and digital voice channel (or two digital voice channels for omnibus), for two digital service channels and for one SparkView TMN communication channel.

Additional auxiliary digital service channels with overall transmission capacity 512 Kbit/s are available for 34 Mbit/s system. They and can be configured in different modes:
  • One 512 kbit/s channel V.28 or V.11
  • Three V.28 channels (up to 9600 bd), and two V.11 channels (up to 19200 bd)
  • Two V. 28 channels (64 kbit/s) and one V.11 channel (128 kbit/s)

What input/output impedance of interfaces is available?
For E1 interfaces (2.048 Mbit/s) both impedances of 75 or 120 ohms are available. For E3 (34.368 Mbit/s) only 75 ohms is available.

What is the consumption in case of 1+1, hot stand by configuration?
For example: 1+1 configuration with two SYM34 modules, one MXM216 module and two RFM18 has power consumption of <28.5W.

What is the output power in case of configuration 1+1, hot stand by?
The output power is equal to the nominal output power of 1+0 configuration.

How do snow, ice and wind affect your antennas?
All antennas are tested on extremely hard climatic conditions including wind, snow and ice. Windload of antenna tower and interface elements must be calculated in the project.

How reliable is SparkWave radio? How did you calculate the MTBF?
The MTBF of our device is 170000 hours (19 years). Statistical calculation was based upon a large quantity of installed links.

What are the advantages/disadvantages of SparkWave radio compared to free air laser transmission except distance?
Free air laser transmission is one of the access network solutions. It has some advantages (low cost, easy to install, high transmission capacity - up to 2.5 Gbit/s, no frequency license is needed, high security of data transmission) and some disadvantages (attenuation and scattering by atmospheric gases; fog, direct sun light and angle sensitivity - only 3-6 mrad). Special laser source (1400-1550 nm) safety for eye (ICE M1 class) must be selected.

In comparison with microwave radio, free air laser transmission channel is much more unpredictable and influenced by numerous meteorological conditions. Transmission availability is very difficult to predict and micro location conditions must be taken into account. Microwave channel characteristics are much more defined. Consequently, for microwave radio transmission it is easier to assure sufficient transmission quality and availability.

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