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Service Providers >> Satellite Internet - Middle East >> Slow Internet - iDirect low C/N 9.8 ?

Message started by duder on Nov 6th, 2010 at 5:01pm

Title: Slow Internet - iDirect low C/N 9.8 ?
Post by duder on Nov 6th, 2010 at 5:01pm
We have a iDirect 3000 modem and a dish about 1.4 meters or so. Our Internet has slowed down to the point its no longer usable. Our provider TS2 says its our equipment. I swapped the LNB and got the same reading. Our dish is peaked 15.9v on the isite software. My company wants to change providers! I want to be sure whats going on before we do that. They say our S/N is 9.8 and thier minimum usable level is 11.5 .  So can anyone out there confirm what there s/n is showing in their modem?
 Thanks duder

Title: Re: Slow Internet - iDirect low C/N=9.8 ?
Post by Eric Johnston on Nov 7th, 2010 at 9:56am
Clarify with TS2 if they are referring to your downstream or upstream C/N.

I am assuming the problem is with your upstream - the transmit direction from you to the teleport hub.

Your upstream C/N, measured at the hub, depends on your dish size, dish pointing and transmit power.  Typically your maximum theoretical uplink C/N will be about 15 dB if your BUC were to be operated at its full power output in clear sky conditions. In practice your BUC will only go to its maximum power output during heavy rain, in order to maintain a continuing service and nominal C/N between about 9 and 11. Under clear sky conditions your BUC will be operating well below its rated power so as to get a C/N at the hub of 9 - 11, exactly the same as all the other remote sites.

If you maximum possible upstream C/N (BUC at full power, clear sky) is only 9.8dB, then I suspect a degraded cable/cable connector on the transmit direction to the BUC, or dish mispointing.

Cable: Any rain/moisture getting into the BUC F connector will corrode the connector and may degrade the sheath and wire for a long distance down inside the cable.  The wire pin may be blackened and almost burned away. The solution is either a new cable or to cut back the end of the cable to good clean bright copper. If the pin is burned away, the contact springs inside the BUC will be damaged also. It is worth using a piece of centre wire and poking it in and out of the BUC socket many times to try and clean up the springs. If the spring contacts have vanished then you need the BUC repaired with a new F socket/spring connector.  A spot of electronic grade silicone contact grease is good at final assembly as this seals the microscopic points of contact from oxygen and moisture. Really good waterproofing is essential.  The ideal F plugs are the watertight axial-crimp variety but they are expensive and so is the special axial crimping tool. Use plenty of self-amalgamating rubber tape or heat shrink tubing with hot melt glue.

Pointing: A value of 15.9 may be entirely satisfactory for receive quality in clear sky conditions. But don't get excited about the exact figure however; it is whether or not the value is the maximum possible value that matters.  Two sites may have perfect maximums of 15.1 and 16.4, but if the second site is 15.9 it is unacceptable as it is not peaked and the transmit beam may be well off the satellite. The transmit beam is narrower than the receive beam so getting to the exact centre maximum matters. Just getting above some arbitary 'good enough' value is irrelevent.

Please would other iDirect sites say what is their downstream signal level ?

Best regards, Eric.

Title: Re: Slow Internet - iDirect low C/N 9.8 ?
Post by duder on Nov 7th, 2010 at 1:09pm
They said its our RX from them, thats why I changed my LNB. Dish has been pointed several times and 15.9 is the max we get, including polarity. The dish is on top of a second storey roof and sand bagged. There is no moisture here at all and the cable is ran up high so I don't think its cable damage, but I haven't checked specifically.
Thanks Eric for the reply!

Title: Re: Slow Internet - iDirect low C/N 9.8 ?
Post by Eric Johnston on Nov 7th, 2010 at 6:55pm
If TS2 have other sites of the same size working on the same beam contour, what are their downstream C/Ns ?

It is strange for there to be a good voltage plus a poor receive C/N.  I don't know the relationship between the two.

I can't think of any likely cause for this.

Straightforward improvements in receive voltage and C/N come from good F contacts and cable, good pointing, no water in feed and dish not distorted.

You might check for dish distortion.  The weight of the feed assembly can pull the sides of the dish forwards.  Put tight threads up-down and across the front. They should just touch ( <1.5mm ) in the middle.  

A rather improbable possibility is the possibility of AC mains currents in the LNB and BUC cables due to slight differences in the earth voltages at the modem and the antenna. This tends to happen when the antenna has a local lightning protection earth (e.g. on the roof or direct to the ground some distance from the building).

Sorry I can't think of anything else.  

Please would other iDirect sites say what is their downstream signal level (voltage 12 - 24V) and say if their system is working well ?

Best regards, Eric.

Title: Re: Slow Internet - iDirect low C/N 9.8 ?
Post by duder on Nov 12th, 2010 at 9:04am
I talked to a couple users that work late. They told me after midnight it is fast. They said until about 7;00am then it starts to slow way down. It is unusable during the day.

I suspect the service is over sold and may not actually be a equipment problem.

However it will be a fight to get them to fix it. If I can get a couple people to post their c/n that will help.


Title: Re: Slow Internet - iDirect low C/N 9.8 ?
Post by duder on Nov 14th, 2010 at 11:21am
I exchange emails with TS2 again. They said its a shared at 10:1 and thats why its slow. I replied... if you sell a service it must work. It has been unusable for over a month now.

Title: Re: Slow Internet - iDirect
Post by Eric Johnston on Nov 14th, 2010 at 8:29pm
Think of it like ten roads merging at a junction into a single motorway.

During congestion, if you have a traffic controller allowing each incoming road to pass for 1/10th of the time you are applying a fair sharing policy. The system is full (100%), and each user gets 10% throughput.

During light traffic, no sharing rules need to be applied, no one is held up and most cars go through at full 100% speed, but with occasional reduction to 50% or 33% when two or three want access simultanaeously.

Ask TS2 if they can implement some kind of fair access policy, particularly during times of peak congestion.

Ask how much traffic (Mbytes) is passed per day by the other users you are supposed to be sharing with?. Get TS2 to show you that you are getting your fair share.

Best regards, Eric.

Title: Re: Slow Internet - iDirect low C/N 9.8 ?
Post by davidbentleywalker on Nov 17th, 2010 at 2:35pm

Sorry to hear about the issues you have been having with TS2.

Bentley Walker can service you with your current equipment. Unlike TS2 we do not have a set contention ratio with our services - We guarantee typical speeds you receive rather than limit them with a set contention ratio.

For example, on a 10:1 connection of 1024/256, the only speeds you are guaranteed are 102.4/25.6kbps. Bentley Walkers 1024/256 guarantee typical download speeds of 600kbps in off peak hours.

We can also upgrade you to the latest iDirect X3 modem free of charge, giving you access to a more efficient service.

If you would like more information please contact me at, Thanks.

Title: Re: Slow Internet - iDirect low C/N 9.8 ?
Post by EFK on Nov 28th, 2010 at 8:40am
“We can give you technical and commercial offer”
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Looking forward to hearing from you soon, we remain.

EFK sales team

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