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Storms causing disconnects

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Munger
Ex Member


Jul 23rd, 2013 at 6:51am  
Hi all

We've had some serious storms over night in the UK. Both my Tooway and Avanti connections went down for a while until the worst of the storms past. They both reconnected Ok without intervention though.

This morning i've connected up and done a speed check and all is working as expected even though the Rx SNR figures are as low as 1 at times. The low i've seen since getting the service installed.

Does anyone have any experience of storm related disconnects. Is it normal?

Also, how low can the Rx SNR go and still keep a connection with data flow?

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Hipolito Gonzalez
Ex Member


Reply #1 - Jul 23rd, 2013 at 7:40am  
i haven't had storm yet, but the band KA is very susceptible to storm and water. I think is normal your situation. If you read about the band KA, you will read about the problems in that situation. I am waiting the winter to review the situation by myself
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Munger
Ex Member


Reply #2 - Jul 23rd, 2013 at 8:10am  
The rain has been really heavy... Both of my systems were offline at the same time. Both were installed by my ISP.

As i'm sure you know, the Avanti has to be aligned carefully using a professional meter by the installer so one has to assume that its been aligned perfectly.
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Munger
Ex Member


Reply #3 - Jul 23rd, 2013 at 8:29am  
Being the end user, you have to assume the person sent out by the isp's to do the install are competent. I know this is not always the case though.

I've had the Tooway system in install mode and the beeps indicate it is aligned satisfactory. On my avant I system I wasn't involved in the setup but did see the guy using a  spectrum analyser during the alignment phase. I don't have the passwords to access the modem to see what the stats are on that system.

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pladecalvo
Ex Member


Reply #4 - Jul 24th, 2013 at 6:08am  
Yes, I have been on Tooway for a year or two and during torrential rain the signal is lost. It returns as soon as the rain eases. There is no loss of signal in 'normal' rain.
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Munger
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Reply #5 - Jul 24th, 2013 at 7:34am  
good to know. the rain we had yesterday wa really heavy. not the normal stuff we see in the UK
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Hipolito Gonzalez
Ex Member


Reply #6 - Jul 24th, 2013 at 10:46am  
Yes, excuse, the english is not my main language. For me, storm means a heavy rain..... When I spoke about if storm could disconnect the ViaSat, is yes, but for my storms. Smiley

The Ka-Band is very susceptible to water. And a heavy rain, is WATER
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pladecalvo
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Reply #7 - Jul 24th, 2013 at 3:39pm  
Quote:
good to know. the rain we had yesterday wa really heavy. not the normal stuff we see in the UK

Mine has only ever gone off in thunder storms when the rain is so heavy it would make your head bleed if you were out in it...and I supposed it would be better not to have one's computer on during thunder storms anyway.  Shocked
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Munger
Ex Member


Reply #8 - Jul 24th, 2013 at 4:35pm  
yep, this was during a serious thunder storm...
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Sudiste
Ex Member


Reply #9 - Jul 24th, 2013 at 5:54pm  
The Tooway system is remarkably tolerant of bad weather conditions as it is after all, designed to work all over Europe, but certainly, in the case of thunderstorms and very heavy rain, synchronisation will be lost.
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Munger
Ex Member


Reply #10 - Jul 30th, 2013 at 2:40pm  
My service has gone down again today. Called up my ISP and there are adverse weather conditions at the base station in Italy that have knocked out approx 2500 users.

Service should be back up again soon they say....
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Munger
Ex Member


Reply #11 - Jul 30th, 2013 at 3:10pm  
Hmmm. Service is back up.

Bit of a cynic but speeds have been poor for days. There's a storm in Italy... The service goes down, comes back up 30 minutes later and the speeds are up...
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alasdairbailey
Ex Member


Reply #12 - Jul 30th, 2013 at 3:15pm  
i thought the same munger. speeds do seem to be dropping slightly again now tho back to the normal peak usage rates.
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Hipolito Gonzalez
Ex Member


Reply #13 - Jul 30th, 2013 at 4:34pm  
About half an hour, my snr was moving from 11 to 1 until then snr reaches the 0 and the system disconnect, later and comes back to 11 but the network register fails. About 30 mins disconnected.
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« Last Edit: Jul 31st, 2013 at 3:55pm by Admin1 »  
 
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Munger
Ex Member


Reply #14 - Jul 30th, 2013 at 4:45pm  
Yep, thats what we had in the UK. SNR all over the place... The modem attempting to connect to other colour spots as well....
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pladecalvo
Ex Member


Reply #15 - Jul 30th, 2013 at 6:18pm  
No problems here in Valencia.
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Eric Johnston
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Reply #16 - Jul 30th, 2013 at 8:03pm  
I believe that the gateway teleport associated with the Valancia beam is called GW7.  Presumably clear sky there. Does anyone know where is this hub ?  I've no idea where is GW8 either ??
If heavy rain exists at a gateway then service in all customer beams associated with that gateway hub will be affected.

So heavy rain in Berlin might affect service in eastern UK, for example.
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Hipolito Gonzalez
Ex Member


Reply #17 - Jul 30th, 2013 at 9:28pm  
Here  if you put your mosue over the beam, you will se the Gateway associated and the location.

http://www.satsig.net/tooway/satellite-dish-pointing-ka-sat-tooway-europe.htm

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pladecalvo
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Reply #18 - Jul 31st, 2013 at 6:02am  
Yes, GW7 it is.
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Munger
Ex Member


Reply #19 - Aug 6th, 2013 at 9:24pm  
Service has been unstable this evening.

Disconnected for 20 minutes. Back online now but RxSNR is only 8!!! Weather conditions my end are fine so I have to assume the other end has poor weather at the moment.

I must admit that I naively thought this service would be stable and only really severe weather conditions would take me offline....
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Hipolito Gonzalez
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Reply #20 - Aug 6th, 2013 at 9:35pm  
Yes, me too and my customers. My SNR is around 8 and a customer is 9 and before was 11.

About a half hour without service
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Admin1
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Reply #21 - Aug 6th, 2013 at 10:03pm  
During rain at your site the downlink bit rate specifically to your site alone, will reduce in steps from about 68 Mbit/s to about 28 Mbit/s as the modulation method and FEC coding applicable to the block of data intended for your site changes (from say 5/6 8-PSK to 1/2 QPSK), to assure minimum errors. Below CNR=3 dB, service will temporarily fail.

If you are limited to an upper bit rate of 20 Mbit/s (per second) by the hub router then this will apply regardless.  If you are the only site affected by rain in your spot beam then the total capacity of the beam will be little affected.  Some types of heavy rain are associated with quite small rain cell dimensions, like less than a mile.  Reduced bit rate due to congestion is only likely if the total capacity of the beam is reduced due to rainfall occurring all over the spot beam coverage, and all sites are receiving with adapted modulation and coding.

Similar modulation and coding changes are applied to the site uplinks, plus uplink power control if your Tx BUC has such a margin. It is really important that your dish pointing is centred as the transmit beam is narrower than the receive beam. When peaking up pointing it is not good enough to just get above some CNR value. You must align to the exact beam centre, which has an illdefined rounded top. It is not easy if you don't understand that the tx beam is narrower.

At the teleport gateway, the uplink has the possibility of uplink power control, e.g. automatically increasing transmit power during rain.  Also, large scale changes to modulation and coding can be applied in both directions. The idea is to dynamically achieve very high bit rates in clear sky, with lower rates during rain.  Such dynamic designs are better for internet access than the old-fashioned, fixed capacity, static coding and modulation, which gave highly reliable  steady low bit rates all of the time.

The objective is to mitigate the effects of rain at 20/30 GHz, which are far worse than at L, C or Ku band. Much larger bandwidths are possible at Ka band and also smaller spot beams with the same satellite antenna size, so it is a case of trying to get the best result for the customer with the science, technology and engineering skills available.
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« Last Edit: Aug 7th, 2013 at 9:20am by Admin1 »  
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paul g
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Reply #22 - Feb 23rd, 2016 at 12:55pm  
Hi, sorry to resurrect this old thread, but did the question of the location of Gateway GW7 ever get answered, I have searched but with no success and the map doesn't bring up the  location.
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