Wanted: Quantity = 20.    New or Used iDirect 5100 routers

If you can help please email:   neil@satcomsolutions.org

Best regards, Eric

OneWeb files for Chapter 11 bankruptcy.

OneWeb has so far launched 74 satellites for its low erath orbit (LEO) constellation, intended to work with 44 earth station teleport hubs, about half of which are either completed or in development. Work has also been done on customer terminals. Successful demonstration tests have shown broadband speeds in excess of 400 Mbps and latency of 32 ms.

The Company and certain of its controlled affiliates have voluntarily filed for relief under Chapter 11 of the Bankruptcy Code in the U.S. Bankruptcy Court for the Southern District of New York.

The Company intends to use these proceedings to pursue a sale of its business in order to maximize the value of the company.

For more information read the full press release here:

OneWeb files files for Chapter 11 bankruptcy.

Wishing them well, both business wise and heath wise.

Best regards, Eric.

Determining the correct output power setting from the modem that will cause your BUC to saturate is not easy.

The purpose is to define the maximum value for operational use, that will never be exceeded. The value varies accoring to your cable length.

You will normally set the operational power somewhat backed off from saturation. The exact value will be told to you by the satellite network operations centre (NOC) during the carrier line up.

Typically the process will involve you chnaging to a specific frequncy and using unmodulated CW carrier.

Your modem output power level will be reduced to minimum and then increased in steps of 1 or more dB, while the carrier level is measured at the NOC. Initially the measured level will go up 1 dB per 1 dB.  This is called the linear operating range.  As the BUC input power reaches a high value the measured signal will start to go up by smaller increments.  If the NOC plots a graph of modem output versus measured satellite carrier the result will look something like this:



The key value is the -1 dB gain compression point, where the curved line falls 1 dB below an extension of the straight linear operation line.

If you are using a Comtech 570L then you may record the DC current and volts used by the BUC. Write these figures down as it becomes you only local measure of what the BUC is doing. (This assumes you are a VSAT and don't have a waveguide power tap on the BUC output and a Agilent power meter or similar. Teleports have output waveguide power monitoring and microwave spectrum analysers to measure any intermodulation when multiple carriers are used.)

BUC manufacturers normally tell you the guaranteed output power (watts) at the -1 dB compression point. The graph above shows a BUC specified at +3 dBW output but actually capable of +4 dBW, at it actual -1dB gain compression point.

I would still recommend using it only at +3dBW as this will give you a clean undistored signal and not exceed th manufacturers rating.

If you go above the -1 dB gain compression point the signal level will increase slightly as the BUC saturates, but the result will be interference to adjcent carriers and distortion of the wanted signal modulation and thus  reduction in quality (increased error rate). Further increase in input power to the BUC may permanently damage the BUC, so be careful adjusting the modem output power. It is important to avoid interference to adjacent carriers.

If you are desiging a link budget it is prudent to use generously rated BUCs so that in normal service the power out is perhaps 6 dB below the -1dB compression point. This gives a good margin for uplink power control to mitigate rain fades. Also, as time goes by the satellite operator may ask you to increase power.

Best regards, Eric.

Thank you Eric for your message.

I found out that increasing of the power in a comtech modem for example (cdm 570l) is not a power settings but a reduction in attenuation. How do i know i have saturated my BUC?

I wrote a comprehensive overview of Hughesnet Satellite internet vs Viasat internet.  This should give anyone here a good idea of the good the bad and the ugly of these products.  https://www.konecteaze.com/viasat-vs-hughesnet-which-is-best-for-your-internet-n... curious to hear the forums thoughts.

Honestly, I don't think its a scam.  WildBlue which is now Viasat, strives to provide good service but sometimes things fall through the cracks.  I don't think anyone was purposely trying to scam you.

I suggest you play around with this link budget calculator:

http://www.satsig.net/linkbugt.htm

Try various dish sizes and transmitter powers and different satellite parameters.   Satellites with small spot beams will have high G/T on the uplink.

http://www.satsig.net/link-budgets/

This index page gives many link budget examples and explanations of the various terms used.

Best regards, Eric

Hi everyone,
I'm new in VSAT technology but i need your help on how to design a transmission plan/Link budget on VSAT link on a c-band and ku-band. This will go a long way in helping my career. I anticipate your response

Hello,

I am using the L2oV feature of the iDirect x7 modem to extend MPLS over VSAT.  I am running into issues with the QoS b/c the iDirect system does not recognize the EXP bit.  Has anyone else tried to get iDirect to prioritize packets based on EXP bit and how did you overcome this obstacle?

The FCC to take 298 MHz of C band frequencies away from satellite.

The FCC has released a public notice:

https://docs.fcc.gov/public/attachments/FCC-20-23A1.pdf

It is with regard to much of the C-band spectrum presently used for satellite communications.

It is proposed to auction off 3.7-3.98 GHz to 5G users and compensate Intelsat, SES, Telesat, Eutelsat, and Star One with some 9.7 billion dollars if these satellite companies can clear the spectrum quickly.

This looks like bad news for anyone using C band for downlinking into North America.

I think the main users have been TV distribution, so I guess they will have to change to Ku band.  Satellite TVRO users with their own C band receive dishes will get no service if the satellites stop transmitting, if they continue transmitting then the C band TVROs will suffer interference from anyone nearby with a 5G device. Sad

According to wikipedia the frequencies used for satellite earth stations are:

C band satellite is vital for high rainfall places.

Your comments welcome.