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1  Service Providers / Satellite Connection in Africa / Contacting satcommander.com and africangateways.com ?
 on: Yesterday at 5:14pm 
Started by Admin1 | Post by Admin1  
Does anyone know what has happened to satcommander.com and africangateways.com ?

I have tried emails to both and all emails fail from here.

News please to me eric@satsig.net

Best regards, Eric

2  Service Providers / Satellite Internet - India, Asia and Australia / Work starts on new Ka band HTS satellite for Indonesia: PSN-VI
 on: Sep 14th, 2020 at 9:27am 
Started by Admin1 | Post by Admin1  
Pasifik Satelit Nusantara (PSN) in association with Indonesia’s Ministry of Communication and Information Technology (KOMINFO) have initiated work on a big new geostationary HTS satellite operating in Ka band to provide satellite internet services to the Indonesian area. At an orbit location of 146 deg east I expect it will have very many tiny spot beams.  It will provide services to Schools, Hospitals and Government offices as well as underserved remote areas. Capacity 150 Gbit/s.

Thales Alenia Space has been engaged as the prime contractor for the project. Two teleports will be constructed, main and backup and many Indonesian staff will be recruited and trained.

More details and large artists image here:

SATRIA press release by Thales Alenia Space

This announcement above follows a Long March 3B launch failure on 9th April 2020 attempting to launch Palapa N1 (cost $220,000,000 capacity 20×36MHz C-band FSS and 9.5Gbps Kaand HTS). That Palapa N1 satellite was intended to replace Palapa-D satellite at 113 East orbit position.

3  Anything else / General and other topics / Re: scpc and tdm/tdma
 on: Sep 11th, 2020 at 7:20pm 
Started by ipman | Post by Admin1  
If you really wanted 100 Mbit/s duplex between just two sites in the same beam coverage I suggest using CDM750 modems with each site transmitting 100 Mbit/s and filling the 48 MHz. With both carriers on top of each other and each site knowing what it is transmitting the interference can by almost cancelled out.  It is called Doubletalk Carrier-in-Carrier.  You will need sufficiently large dishes at both ends.
Check with Comtech that what you propose is feasible.

REFERENCE http://www.comtechefdata.com/files/datasheets/ds-cdm750.pdf

4  Anything else / General and other topics / Re: scpc and tdm/tdma
 on: Sep 11th, 2020 at 10:02am 
Started by ipman | Post by Admin1  
A small VSAT network for internet access purposes, might comprise a teleport hub and 100 remotes. The hub would transmit a 4 Mbit/s carrier, which would be received by all sites, so each site could receive downloads at up to 4 Mbit/s for short periods. The outlink download carrier would be called TDM type and might use a DVB-S type frame structure. Blocks/packets of data would be addressed to particular VSAT sites using IP addresses.
The remote VSATs would only transmit occasionally and would use TDMA. The 100 sites might be grouped in two groups, so that 50 sites operate on one return link frequency and 50 sites on the other return link frequency. The hub would need two TDMA receivers. The burst bit rates of the return links might be 256 kbit/s.

It is hard to see how 100 VSAT site users could afford to pay for 48MHz of satellite bandwidth. Do you have such customers?

5  Anything else / General and other topics / Re: scpc and tdm/tdma
 on: Sep 11th, 2020 at 9:40am 
Started by ipman | Post by Admin1  
Single Channel per Carrier (SCPC) refers to operation of continuous low bit rate carriers, generally in point to point configurations.  The expression 'Single Channel' is somewhat historical since is refers to traffic comprising one analogue audio voice signal input.  Nowadays the 'traffic' over a 10 kbit/s or 64 kbit/s or 128 kbit/s carrier might be digitally encoded voice.

An SCPC carrier might operate 24/7 or might be set up on demand for just of a minute or two when a phone call is made.

Once the bit rate gets up higher the expression 'Time Division Multiplex' (TDM) becomes more applicable as the data stream begins to comprise a sequence of frame blocks or packets containing a variety of end user traffic, voice, data, video etc.

Time Division Multiple Access (TDMA) is when several sites, transmit intermittently on the same frequency, thus sharing the same satellite bandwidth. See my description of how TDMA works.

Regarding your proposed network. Please explain more. Do you plan a hub as well as the 100 VSATs?  What traffic to and from the hub. What traffic to and from each VSAT site.  Star configuration or mesh configuration?. 

A total of 200 Mbit/s through a 48 MHz transponder sounds like a difficult challenge.

6  Anything else / General and other topics / scpc and tdm/tdma
 on: Sep 10th, 2020 at 3:39pm 
Started by ipman | Post by ipman  
what is scpc and td/tdma system in earth station /vsat satellite system? considering ku band with 48 MHz space segment ,how can we design system of 100Mbps duplex with 100 vsat stations.

7  Service Providers / Maritime and Mobile satellite communications / Sailor 900 VSAT High Power Conversion kit for sale. Ku band 20W
 on: Aug 31st, 2020 at 1:46pm 
Started by Admin1 | Post by Admin1  
Sailor 900 VSAT High Power Conversion kit for sale. Ku band 20W

...


The Antenna Conversion Pack consist of following PCBA's
VSAT Interface Module (VIM3) P/N 62-148091
NGW BUC 20Watt P/N 62-149173

Box 1
Equipment
Antenna Control Unit P/N 407016C-00500 ACU

SAILOR 900 VSAT High Power
Accessories:
407016C-T19 SAILOR ACU 19" Model 7016C
687016C-T19 SAILOR ACU Accessories
98-138976-G SAILOR 900VSAT System (Ins)

Box 2
Equipment
P/N 407021C-00500 SAILOR 900 VSAT Power RF Pack
Accessories:
407021C-THR SAILOR 900 VSAT High Power RF
67-152322 Accessories Kit for 407021C
98-151864-b SAILOR 900HP Conversions Kit H

If interested email SatBBC at sales@satbbc.com

Posted by forum admin. From email 31 Aug 2020.

8  VSAT technology and installation / iDirect Forum: hubs and terminals / iDirect modem sales: Evolution X5, e8350, Evolution X7
 on: Aug 31st, 2020 at 1:31pm 
Started by Admin1 | Post by Admin1  
The following modems are for sale:

iDirect Evolution X5 Used.Tested, Unblocked. $595
iDirect Evolution X5 New $1150
iDirect e8350 Tested. Guaranteed to work $1250
iDirect Evolution X5 Used, Tested $1000

...

A number of iDirect modems are for sale.  Sale ends 5 Sept 2020.

If interested email SatBBC at sales@satbbc.com

Posted by forum admin, from email.

9  Service Providers / OneWeb LEO satellite constellation discussion forum / Re: OneWeb satellite constellation in new ownership 2020
 on: Aug 31st, 2020 at 1:17pm 
Started by Admin1 | Post by Admin1  
26 Aug 2020:  The FCC has granted OneWeb‘s service access to the US market using 2,000 satellites with a V-band payload at a height of 8500km.

The 2000 satellites comprise: 720 Ku/Ka band satellites being upgraded with V band payload, plus 1280 additional satellites.

The launch and operation of these satellites will be at the discretion of the U.K. government, through which the application for orbit access is being processed.

Approval will be subject to review of OneWeb's plans for dealing with old end-of-life satellites so that space debris is mitigated.

For satellites in 1200km orbit, OneWeb intends to first lower the circular orbit to height of 1000km. (2 burns of deltaV approx 48m/s) plus a later transition to an orbit of 250 x 1000km (deltaV approx 199m/s), thus allowing for atmospheric drag at the lower end of the ellipse to gradually bring the satellites back into the atmosphere.

Recovering a satellite from 8500km down to 250km, needs more fuel, sufficient for deltaV approx 1113 m/s.

If anyone can calculate the deltaVs independently and confirm (or otherwise) my calculations I would be pleased to hear.

10  Service Providers / Satellite Connection in Africa / 【Eutelsat Acceptance Test】Dolph MIcrowave 3.7 Meter Earth Station Antenna Delivery and Test
 on: Aug 28th, 2020 at 8:51am 
Started by Dolph Microwave Co.,Ltd. | Post by Dolph Microwave Co.,Ltd.  
DH 3.7m ESA Antenna Systems has finished delivery and test for customer, which is for satellite broadcast TV receive and transit services. Dolph Microwave also offered Tx transmit waveguide kits and RF device besides antenna.

...

DH 3.7 Meter DR C-band Antenna


It uses Eutelsat satellite as signal transfer, who has strict requirement of side lobes, far side lobes and cross-polarization isolation. Antenna manufacturing accuracy and errors must be very critical. Otherwise it will be useless.

Reflector manufacture technology and positioning pin are unique design, which assures high accuracy of antenna reflector and electrical performance after reassemble to guarantee antenna compliance with Eutelsat approval requirement.

...


Device included in this project as following:

Dolph Microwave 3.7 Meter Earth Station Antenna with a semi-automatic pointing controller and an additional satellite antenna controller.
1:1 200W C-band SSPA redundant from Algal Microwave.
Norsat LNB and receive components.
Comtech satellite modem.
Dolph Microwave TX waveguide integration from Hub to across upper Az axis including rigid/flexible waveguide, crossguide coupler, high power termination etc.
All device in this system is high stability and easy maintenance to improve reliability and high quality service.

Dolph Microwave eager to offer stable device for cooperator. Lead time is adjustable based on production schedule. Highly qualified engineers guarantees company’s work on schedule, and technical support is provided in 24/7.