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Satellite Communications/Questions
| Subject | Date Asked | Expert |
| Link Availability | 2/6/2012 | Luis Emiliani |
| Q: 1) How to convert link availability in a year to link availability in a month... 2) How to ... A: the basis of the model is found here : ITU-R Rec. P 581: http://www.itu.int/rec/R-REC-P.581/en ... | ||
| Steps for a SCPC link | 2/5/2012 | Luis Emiliani |
| Q: Greeting of the day, My question is, what are the steps that i have to follow,if i have to transmit ... A: there are quite a few steps from getting the content ready to uplink and distribution. ... | ||
| Back-off | 2/3/2012 | Luis Emiliani |
| Q: Sir, for single carrier operation, while selecting the rating of BUC, what is the back off to be ... A: it is not about failure rate, understanding as failure an event in which the hpa stops working. it ... | ||
| Back-off | 2/2/2012 | Luis Emiliani |
| Q: Sir, for single carrier operation, while selecting the rating of BUC, what is the back off to be ... A: for SSPAs, you need to make sure you do not exceed the 1dB compression point. for single carrier ... | ||
| PHASED ARRAY ANTENNAS | 1/27/2012 | Luis Emiliani |
| Q: With internet support I am able to get the formula on the parabolic dish antenna off-axis radiation ... A: after googling the subject i found a few links. i suggest you try these references. they will ... | ||
| Slow browsing on SCPC/SCPC Link | 1/26/2012 | Luis Emiliani |
| Q: I have 10/5Mbps SCPC/SCPC link. My download could reach to 9.5Mbps but our browsing is worse like ... A: there are various reasons that could cause that performance limitation, such as window size ... | ||
| SCPC Vs TDMA | 1/24/2012 | Luis Emiliani |
| Q: Sir, 1) for TCP / IP traffic, what is the typical throughputs on the SCPC and TDMA links ?? 2) Can ... A: this topic is not straightforward. the encapsulation efficiency depends on various factors, ... | ||
| hpa and buc | 1/18/2012 | Luis Emiliani |
| Q: Please explain if output of buc is r.f. frequency what does hpa do i mean what characteristic of ... A: a block up-converter or BUC for short is a combination of a frequency up-converter and a solid state ... | ||
| accessing scpc remotes | 1/12/2012 | Luis Emiliani |
| Q: can we access scpc remote modems (radyne/paradise) from pc in the hub side using the web interface ... A: i believe this application note answers your question ... | ||
| Relation between FEC and bandwidth | 1/11/2012 | Luis Emiliani |
| Q: I was looking for some information regarding the relation between FEC and the bandwidth. So I ... A: the purpose of coding in a communications link is to enable the detection and recovery/correction of ... | ||
| Hi | 6/12/2011 | Dave Suffys |
| Q: what is Output Back off? what is decoding & encoding? regds Bj A: Output back-off refers to the difference in power that is actually used in an amplifier with the ... | ||
| inclined orbit | 6/10/2011 | Dave Suffys |
| Q: - When a satellite is in inclined orbit How long can he stay there? - If it is said that there is ... A: The lifespan of a satellite is usually limited by the amount of fuel it carries on-board. This fuel ... | ||
| hi | 6/5/2011 | Dave Suffys |
| Q: Sir, 1)what is output back off? what is ratio of IBO/OBO? 2)how RF signal frequencies traveled ... A: See my answers below your questions. 1)what is output back off? what is ratio of IBO/OBO? For the ... | ||
| Signal level and C/N | 6/3/2011 | Dave Suffys |
| Q: I am well aware about the definition of Signal level(in dbm/dbw) and C/N(in db) but I normally get ... A: Without anything connected to the spectrum analyser, you the noise floor of the analyser (which is ... | ||
| satelite dish | 6/3/2011 | Dave Suffys |
| Q: So satelite dishes for tv operate by transmitting RF? thanks gia A: Your question is rather unclear. Satellite dishes (at home to receive the signal) receive the RF ... | ||
| Intermodulation calculation in multicarrier TWTA Amlifire | 6/2/2011 | Dave Suffys |
| Q: greetings for the day,I want to know the formula to calculate Intermodulation carriers in ... A: Intermodulation produces unwanted carriers. The frequencies on which these carriers are present at ... | ||
| calculation of OFD | 6/1/2011 | Dave Suffys |
| Q: How can i calculate Operational flux density (OFD)? Data given as SFD = -84.5dbw/0k trasponder bw = ... A: The required OBO is usually determined by the satellite operator. It depends on the operating mode ... | ||
| Signal level and C/N | 5/26/2011 | Dave Suffys |
| Q: I am well aware about the definition of Signal level(in dbm/dbw) and C/N(in db) but I normally get ... A: Indeed, a good carrier-to-noise (C/N) can be ruined by having an absolute receive level that is too ... | ||
| overall C/N | 5/26/2011 | Dave Suffys |
| Q: Sir, 1) what is over all Down link C/N? what is formula & pls explain with detail example. 2)what ... A: This is a question that is too long to answer here. Basically you want to have a look around on the ... | ||
| Satellite communication | 5/24/2011 | Dave Suffys |
| Q: WHEN WE RECEIVED C-BAND SIGNAL IN DOWN-LINK,First it down converts the signal in 70 MHz IF, then it ... A: Indeed, there are downconverters that convert from C-band to L-band. However older equipment uses IF ... | ||
| HPA | 5/22/2011 | Dave Suffys |
| Q: What parametres are taken into account when designing of HPA(i mean watt). ex. for 2 channels of ... A: The size of the HPA is determined by the link budget and the needed EIRP for a carrier. From the ... | ||
| Receive interference | 5/21/2011 | Dave Suffys |
| Q: We have two 6.3 m Ku band Vertex antenna. In one antenna called antenna A we are having about 12 ... A: When a signal is transmitted from satellite to the earth station and there is rain, it experiences ... | ||
| Turbo coding | 5/15/2011 | Dave Suffys |
| Q: Please explain the diferrent kind of coding used in Satellite communication and specially Turbo ... A: That's a very general question and would require a lot of explaining ;-) Basically there are 2 ... | ||
| Advantages of BUC Vs SSPA in VSAT | 5/11/2011 | Dave Suffys |
| Q: What are the advantages and disadvantages of a 1+1 VSAT system using SSPA Vs BUC in terms of ... A: A BUC is has typically an L-band input and converts first to the desire RF band (C/Ku) and then this ... | ||
| cross pol. | 5/2/2011 | Dave Suffys |
| Q: Please tell me what is cross pol. what is its need. Regards A: Cross polarisation can refer to the interference that is the result of the "leakage" of signals from ... | ||
| B.W. and S.R. | 5/1/2011 | Dave Suffys |
| Q: Sir, In our serial digital setup(encoder) we have parameters as S.R-7.07, roll off-.35, in ... A: It all depends on what you define as the bandwidth of a signal. Typically, the term "noise ... | ||
| modulation | 5/1/2011 | Dave Suffys |
| Q: Sir, how are you? I want to more clear about modulation. a)What is the main purpose of ... A: a) a digital signal cannot be transmitted over satellite as such. It needs to be modulated onto a ... | ||
| symbol rate | 4/29/2011 | Dave Suffys |
| Q: What is SYMBOL RATE? if symbol rate 4300ksps and the modulation technique is QPSK, then what is the ... A: I already answered a similar question on this forum. See ... | ||
| power amplifire | 4/29/2011 | Dave Suffys |
| Q: In TV station, up converter send signal to the power amplifier(twta) then it goes to the satellite. ... A: In order to transmit the modulated carrier with enough power to the satellite it needs to be ... | ||
| Satcom - Link Budgets | 4/28/2011 | Dave Suffys |
| Q: Requesting you to pls tell me what is the significance of composite C/N in satellite link budget ... A: The overall or composite C/N is indeed the result of all contributions to C/N that will be present ... | ||
| Satcom - Link Budgets | 4/28/2011 | Dave Suffys |
| Q: Requesting you to pls tell me what is the significance of composite C/N in satellite link budget ... A: The composite C/N is the result of adding the UL C/N and DL C/N which are separately calculated in ... | ||
| coaxial cable amplification | 4/27/2011 | Dave Suffys |
| Q: Renovated my home about 12 years ago. Installed individual coaxial runs in 7 rooms which all meet ... A: difficult to pin a single model that would be best. All depends on how many dBs of amplification you ... | ||
| Radio Communication | 4/25/2011 | Dave Suffys |
| Q: What factors affect the quality of satellite transmission? A: The quality of for example a video transmission is determined by the bitrate that is used for that ... | ||
| t.v. channel uplinking | 4/24/2011 | Dave Suffys |
| Q: how can so many t.v. channels are transmitted over a single same frequency and the same symbol rate ... A: For video over DVB transmissions, MPEG compressions is used that can bring down a video signal to a ... | ||
| calculation of OFD | 4/22/2011 | Dave Suffys |
| Q: How can i calculate Operational flux density (OFD)? Data given as SFD = -84.5dbw/0k trasponder bw = ... A: There is an error in the code of that site. Where it says ... | ||
| why can't we transmit with mesh antenna? | 4/22/2011 | Dave Suffys |
| Q: My question is why can't we transmit with mesh antenna? The reason is only the difference in gain ... A: That's a good question. In order to be allowed to transmit with an antenna, it needs to be ... | ||
| satellite pointing | 4/21/2011 | Dave Suffys |
| Q: sir, i am not able to point any satellite manually, LNB moving is very difficult for, can you help ... A: This is a very general question. It would take a long time to explain here. I suggest that you have ... | ||
| Variable Coding and Modulation on DVB-S and DVB-S2 | 4/20/2011 | Dave Suffys |
| Q: greetings. I have 18Mhz bandwidth and i want to run Dvb-s and DVB-s2 channels on same. is it ... A: This was suggested in the DVB-S2 standard as a backward compatible mode. However no-one in the ... | ||
| Maximum permissible levels of off-axis e.i.r.p. density | 4/19/2011 | Dave Suffys |
| Q: Hai for KU Band Maximum permissible levels of off-axis e.i.r.p. density i have to follow ... A: 728 refers to Vsat antenna systems and typically have small antennas like 1.2 m and typically run ... | ||
| Parabolic Antenna pattern | 4/18/2011 | Dave Suffys |
| Q: What will be the effect of having less than the specified 15dB difference from main lobe to the ... A: The reason for sidelobes needing to be below a certain difference to the main lobe are two fold: 1) ... | ||
Satellite Communications
Answers by Expert:
Dave Suffys
Top Expert on this page
Expertise
Questions related to design of satellite communication links.
Experience
Satellite communication, link budgets, DVB-S2, ACM
Organizations
Newtec
Education/Credentials
Telecommunications engineer
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