VSAT, Networking, and Hobby

I was on Ngurah Rai airport Bali on May 22th,2011. When in process of boarding to my plane, I was looking at a interesting color scheme plane beside my plane that I used to board. So, I get it photograph I can tell it interisting, because that color scheme I remember it used by Garuda Indonesia long time ago. Then, I search some answer why there is a plane of Garuda Indonesia use that color scheme. At last, I get information that this retro color scheme used for Garuda Indonesia new units of Boeing 737-800 NG. Nice move of Garuda Indonesia, to remind us what their painted color plane in the 1960s until 1980s.

There are many types for earth station antenna, which are : 1. Prime Focus Feed Most popular due to its excellent efficiency (approximately around 62%) Because of its relatively large surface, the prime focus antenna is less sensitive to small directional deviations and there is a better chance of receiving signals outside the normal footprint. Usually limited up to 4.5 mtr diameter Sometimes problem with OMT adjustment for "prima" Cross-Polar Isolation (CPI) characteristics Because of the LNB is mounted centrally, a lot of the incoming signals are blocked by the LNB on the way to the antenna surface.   2. Offset Feed Better efficiency due to reduction of Feed (and spars) "blocking" Simple to deploy, usually to Fly-away or Transportable SatCom terminals Much easier to adjust in achieving very accaptable Cross-Pol Isolation (CPI) Due to its simple construction, while satisfying the requaired ruggedness of Feed support, normally these are produced max ...

Now, let's me talk about measurement unit that used in telecommunication, especially in VSAT.  dB (deciBell) unit copes with logarithmic and relative parameter. dBm is a standard unit for measuring levels of power in relation to a 1 milliwatt (mW) reference signal. dBm and dBW related to "absolute" power/level. 0 dBm (=mW) means power of 1.0 mW dBm is similar to dB, or decibel , except that where dB is relative to the power of the input signal, dBm always relates or absolute to a 1 milliwatt signal (as measurement unit). A minus sign before the dBm indicates a loss and a plus sign or no sign at all before the dBm indicates a gain. A guide in this relative unit can seen below :  10 dB means 10 times than original   7 dB means 5 times than original   3 dB means 2 times than original   1 dB means 5/4 times compared to original   0 dB is 1X the original  -1 dB means 4/5 times compared to original  -3 dB means 1/2 times than original -10 dB means 1...

Hi everyone, now time for another kit of mine, Masurao (GNX-U02X)   This is customized design of MS built for Graham Aker (Mr. Bushido) by Billy Katagiri and his team, which Graham demand great speed and excellent melee combat capabilities As for Billy worked before for Union, this MS trully resemble MS Over Flag. The Masurao is powered by a GN Tau Drive and also capable of accessing a Trans-Am-like system (based on note of Professor Ralph Eifman) that allows it to fight on the same level as its rival 00 Raiser. This sharp snap-fit kit of Masurao will be fully articulated with polycapped joints upon completion. Includes a pair of GN beam sabers and optional hands (open hands and grip hands) (Hint : Graham Aker a.k.a Mr. Bushido voice actor is Yuuichi Nakamura also voice actor of Saotome Alto from Macross Frontier)    The horns at Masurao's head can move forward and backward   With unique sole   Equipped with two beam saber; Large beam saber named How...

Sun Outage (or Solar Outage) is a severe interference event generally resulting in the loss of satellite communications service caused by the physical geographical alignment of the sun, satellite and earth-station coming into a direct line. Look the picture above, let's assume that virtual orbit of Sun with position from A to N. When an Earth station and Satellite Communication is In-Line with the Sun position, then the Earth station receive heavy and very strong NOISE for Rx-path. This Sun Outage happens because Sun is the largest Noise Source with 'complete' Spectrum. Sun Outage will be experienced by Satellite communication twice on every year, which are in March and September for a few days, duration of approximately 10 to 20 minutes a day, starting from the most West Earth-Station. From the picture, Station A located in West of Station B, will have earlier Sun Outage (usually before noon) compared to Station B.

Intermodulation occur when the non-linearity of a device or system wth multiple input frequencies causes undesired otputs at other frequencies. In communication system (include in satellite communication), this means that signals in one channel can cause interference with adjacent channels. As the spectrum become busier and the channels become more tightly spaced, minimizing intermodulation distortion becomes more important. To measure this Intermodulation, we can combine two equal power signals with a set frequency spacing at the input of the device-inder-test DUT). The output spectrum will look like figure below ; The two largest signals are the amplified carrier signals, and the smaller signals, moving away from the carries in both directions, are the 3rd order, 5th order, and 7th order intermodulation products, respectively. The frequency spacing between all the signals is equal. The interest parameters here as follows : Carrier (C) : This is the power of the carrier signal i...

"When Terrestrial Communicatios Infrastructure is Damaged, Destroyed, or Overloaded, Satellites = Operability" Satellite communication are : High Survivable (Physical survivability and robustness) Independent of Terrestrial Infrastructure Able to Provide the Load Sharing and Surge Capacity Solution for Larger Sites Best for Redundancy : They add a Layer of Path Diversity and Link Availability Satellite Systems Perform Effectively When : Terrestrial infrastructure is damaged, destroyed, or overloaded Interconnecting widely distributed networks Providing interoperability between disparate systems and networks Providing broadcasting services over very wide areas such as country, region, or entire hemisphere Providing connectivity for the "last mile" in cases where fiber networks are simply not available Providing mobile/transportable wideband and narrow-band communications Natural disasters or terrorist attacks occur. Satellites are the best and ...

Cross Polar Isolation (CPI) In installation and pointing/peaking antenna, Orthogonal Mode Transducer (OMT) must be set to be as precise as possible to get the best CPI value. above is picture of OMT Feed assembly include with BUC and LNB The minimum value for CPI is 30 dB (better will be good) in Linier Polarized Antennas. The reason is for our receive (Rx)-side as not to get interferenced (distrubed) by other (polarity) Down-Link users, therefore our transmit (Tx) shoild as well not interfere other users that operates at 90 deg (Orthogonal) Polarization. Note : In LH/RH Circular Polarizations, usually CPI of 27dB (=AR of 1.09) is acceptable enough. picture above is careless/miss-aligned OMT setting

Frequency Spectrum Allocation   As you can see the picture above,  that the frequency spectrum that allocated in telecommunication. This post is focus only to frequency spectrum that used in satellite communication. Intermediate Frequency (IF) Band     Mainly used in Satellite modem equipment in modulator and demodulator side.      Range of spectrum is around 70 MHz (50 MHz to 90 MHz) L-Band     Also mainly used in Satellite modem equipment in modulator and demodulator side.     Range of spectrum is 950 MHz to 2150 MHz C-Band Primary used in satellite communication for frequency used communication between ground segmen and the satelllite. For this range of spectrum, Uplink frequency (from ground segment to satellite) is around 6 GHz and Downlink frequency (from satellite to ground segment) is around 4 GHz. Ku-Band Used in satellite communication for frequency used communication between ground segmen and th...

MTU (Maximum Transmission Unit)  MTU is the size (in bytes) of the largest protocol data unit that the layer can pass onwards. MTU parameters usually appear in association with a communications interface (NIC, serial port, etc.). Standards (Ethernet, for example) can fix the size of an MTU; or systems (such as point-to-point serial links) may decide MTU at connect time. A larger MTU brings greater efficiency because each packet carries more user data while protocol overheads, such as headers or underlying per-packet delays, remain fixed; the resulting higher efficiency means a slight improvement in bulk protocol throughput. A larger MTU also means processing of fewer packets for the same amount of data. In some systems, per-packet-processing can be a critical performance limitation. To test your MTU connection, we can use ping test with command : ping xxx -f -l yyy while yyy is packet size.  example : C:\Users\admin>ping yahoo.com -f -l 1472   Pinging yahoo.com [209...

Ping..... Ping is one of the usefull and effective command in determine network test connectivity with another IP host. Typing PING followed by specific IP address at command prompt will immediately tell whether there is connectivity between your computer and the other host. Ping test is often referred as testing the protocal stack, because the ping command moves from Layer 3 OSI model to Layer 2 and then Layer 1. Ping uses the ICMP protocol to check for connectivity. Please note... ping will not always pinpoint the exact of the problem in the network, but it can help identify the source of the problem, one of important first step in network troubleshooting. Ping command There are also a number of options that you can use with the PING command. The available options are listed below. -t Pings the specified host until stopped -a Resolves addresses to hostnames -n count Number of echo requests to send -l size Send buffer size -f Set Don’t Fragment flag in packet -i TTL Time ...

Communications by Satellite Satellite communication "Transponder" operates like REPEATER , which is very similar to Terrestrial Radio Communication. The term "Transponder" here, in satellite itself, easier for satellite operator to maintain power liniarization if divided into some lot of frequency. Usually,1 transponder consist of 36 MHz in bandwidth (certain satellite use 72 MHz bandwidth). Main functional similarities between Terrestrial Communication and Communication via / by Satellite are : Input signal at antena ( F-in = F-Rx ) relatively weak and coming from many directions. Mixing ( F-Rx ) with Local Oscilator, therefore results Frequency Translation ( F-out not equal to F-in ). F-out (F-Tx) of Repeater is filtered, amplified, then with relatively very High Power is transmitted by Antenna, for greater distance and wide area coverage (benefit of using satellites) Repeater's site is always placed on high surface, structure , etc, to fulfill and ...

Hello everyone.... For today's post, i will show you one of my hobbies....yeah! GUNDAM Well, i already finished to build my O Gundam A.C.D kit and also to review it. I really like this kit, do a lot panel lining on it too. Overall, this kit is really great, look simple in design but really have good articulation and detail for HG kit. Good work, Bandai. Hope all of you enjoy these pics Coloring, really not to do a lot of thing...at least you just can do some panel lining   Bandai has getting better on articulation on HG model, with no exception on O Gundam. Despite on simple design (RX-78 design), you just can make hand, body, leg rotate all over, even can move the hand over back to grab the saber  Also, good design on shield holder, with handle like that, slip on the hand and not to make any hole the Gundam's arm What a pose....like a final pose on final stage versus Exia Repair. (hmmm....O Gundam ready to kick his ass, despite the fact that his ass kicke...

In this occasion, i want to share about Satellite communication. First, please look at the picture below, Planets of our Solar System God created Moon as our Earth satellite. In order to broading our communication, people tend to use artificial satellite for communication. Based on orbits, these are the type of satellites : Low Earth Orbit (LEO)              Height : 750-2500 Km,       Period : 2 - 2.5 hours Medium Earth Orbit (MEO)       Height : 7500-10000 Km,   Period : 4.5 - 6 hours High Earth Orbit (HEO)             Height : 15000-20000 Km, Period : 11-12 hours Geo-Stationary Orbit (GSO)      Height : 36000 Km,             Period : 24 hours Incline Orbit Satellite (drifting > 0.1 deg. N-S an...

There is always a first for everything Yes... It will any first for everything we done, include in this blog activity. So, this is my first entry  welcome,everyone So, what will i plan for fill in my blog...? of, course, anything...any contents that i want to write and to share, because this's my blog! This blog will be full with anything in my head, my opinion, which i want to share on internet Pertamax,gan...hahaha...