Friday, September 4, 2009

High Speed 200 Mbps Microwave Modem

The MM200 is anideal solution for both new and retrofit microwave link installations.Maximum flexibility is achieved by an internal data multiplexer thatcombines up to four user selectable data paths into a single datastream. Interface choices for each include OC3 Optical, DS3, E3,STS-1, STM-1, SMPTE, DVB, ASI, Parallel, Overhead andT1/E1(Wayside). The IF can be field-configured with 1 to 4 chan-nels providing total flexibility. Each channel can operate up to 7Mbaud. The 2U chassis can be configured for simplex, duplex orspace diversity

Nucomm, Inc, is proud to introduce the MM200 SeriesMicrowave Modem. This innovative and highly flexible platform isconfigurable for data rates between 1 and 200 Mbps. The unitallows complete control over modulation density and channel band-width for efficiencies up to 6 Bps/Hz. The unique architecture of theMM200’s IF allows large improvements to fading and multi-pathvia multiple digital equalizers when used with the NucommFT6/FR6 microwave Transmitter and Receiver.

• Up to four user-selectable data/overhead interfaces
• 4, 16, 32, 64, 128 and 256 QAM operation
• Space diversity option
• Seamless hot-standby switching (optional)
• Ideal for new microwave links, upgrades or retrofits
• Wayside and/or overhead options• Reed-solomon forward error correction
• Adaptive equalization• Remote control from network or serial interface
• Companion to the Nucomm’s FT6/FR6 microwave system

High Speed 200 Mbps Microwave Modem Ebook download

Ericsson Mini Link Microwave Radio Link

Ericsson’s medium capacity point-to-point microwavesolution, MINI-LINK E, is designed for operation inany type of network. The compact microwave radiocontains cutting edge technology and provides maximumreliability. With a Mean Time Between Failure (MTBF)exceeding 30 years MINI-LINK E offers continuoushigh performance. Standardized interfaces ensure opera-tion in all types of networks.MINI-LINK E can be configured to meet any networkrequirement for capacity and range. It provides radiotransmission links from 2 up to 17x2 Mbit/s, operatingwithin the 7 to 38 GHz frequency bands.

Download Free Ebook Ericsson Mini Link Microwave Radio Link PDF file

Microwave Planning Before and After.

Before getting to the nuts and bolts of designing a link, some fundamental terms and concepts need to be reviewed
Free Space Loss.
Fresnel Zone.
Receive signal level.
Receiver sensitivity
Antenna gain
Transmit Power.
Effective Isotropic Radiated Power
System Operating Margin.
Multipath Interference.
Signal-to-Noise Ratio.
Why Perform an SOM Calculation?
What Is the Minimum SOM Needed?

But even if your Fresnel zone is partially blocked, it is still possible to get a link, provided that your system was designed to have a strong signal at the other end of the link. In planning long-range microwave links where you are not sure that you have unobstructed line-of-site and clear Fresnel zone, an RF path analysis should be done. There are many software packages available that have terrain data and can create a path profile from a set of latitude/longitude coordinates. But these programs can only indicate for certain if a link will not work due to terrain obstruction. A clear path on paper is not a guarantee that your link will work, since it does not show trees or buildings. So even a “clear” link might have 80-foot trees in the way that could block the signal

RF Microwave Radio Interview Questions and Answers

Question 1: Define RF Signals?
Answer : Radio Frequency Signals are high frequency AC Signals Composed of EM Energy.

Question 2: When we get the higher signal strength in RF?
Answer: If Amplitude of the RF signal is higher then Signal Strength will be higher so as vice versa.

Question3 : why we Prefer Transmission through RF and Microwave ?
Answer : Broadband Information Signals required High Frequency Signals.

Question4: what is the speed of prorogation of RF Signals.
Answers : Speed of Propagation of RF Signals is equal to that of speed of light.

Question5 : what happens when multi path reflection occurs in RF Signal.
Answer : Signal Degradation and Holes in Coverage area of Microwave Network.

Question6: How the Antenna Gain is Calculated?
Answer : First of all direction is determined and then we calculate what would be power level at the same distance from the isotropic radiator.

Question7: when VSWR(Voltage standing Waves Ratio? occurs.
Answer7 : when their is mismatch in impedance and signal is reflected at point of impedance , which will result in decreased amplitude.

Question8: which is the commonly used transmission line RF and Microwave.
Answer: Coaxial Line.

Microwave Radio Parameters

Loss , Reflection , Refraction , Diffraction , Polaraziation , Scattering , Absorption , Fading , Intereference , Attenuation are the parameters of microwave radio communication system which will be discussed here by.

Loss : loss means decrease in siganl amplitude , which can caused because of many reasons like : resistance of cable , connectors , loss because of heat impedance mismatch.

Microwave Frequency Allocation range.

WPC and SACFA has declared the microwave frequency range as.

6 and 7 GHz frequency range for Distance 5-50 Kms also called as Long Haul.

15,18 and 23 GHz Frequency Band are used for Access Networks distance 1-15 Km also called as Short Haul.

Who does the Microwave Frequency Allocation.?

WPC : Wireless Planning committee , it is a government wing which take charges from operator for use of microwave frequency pair.charges they take are based on bandwidth used and annual gross revenue of the company.

SACFA : Standard Advisory Committee for frequency Allocation , it is government wing which allocates frequency and also gives tower height clearance to the telecom operators.

SACFA,ensures this thing that their is no inter fence between existing users before allocations of frequency.

SACFA, Checks before giving tower height clearance that , it should not cause obstruction to existing microwave links of other operators and should not be in a funnel zone of aircraft.

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