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Service Providers >> TooWay and KA-SAT satellite >> Tooway SNR RX weakening
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Message started by Gavarres on Aug 8th, 2019 at 11:41am

Title: Tooway SNR RX weakening
Post by Gavarres on Aug 8th, 2019 at 11:41am
I have Tooway for 4 years now. The location (near Gerona in Spain) is at the edge of three beams (see attachment in the next posting). I am tuned to beam 3.
My Tooway SNR RX signal is very weak. Just around 10.0 dB
When I installed the dish the signal was around 11.3 dB and degraded in 4 years to around 10 dB.
As I wondered if the LNB was deteriorating the provider gave me a replacement LNB a few days ago. But that gave the same SNR RX of around 10.0 dB. The provider now thinks it could be the beam strength from the satelite itself. He is consulting collegues if connecting to another beam could be a solution (which I doubt).

Has anyone encountered a similar problem?
Can the modem be a problem?
Could the cause be something totally different?

Looking forward to your suggestions.

Title: Re: Tooway SNR RX weakening
Post by Gavarres on Aug 8th, 2019 at 12:22pm
See attachment for beams
Tooway.jpg (60 KB | 6 )

Title: Re: Tooway SNR RX weakening
Post by Admin1 on Aug 9th, 2019 at 5:14pm
My guesses at possible explanations:

Your dish has moved slightly and is no longer pointed very accurately at the satellite.

The dish surface has corroded or is not clean. The degraded surface absorbs some of the signal.

The feed horn window must be clean and dry with no spiders or damp.

On the downlink to the customer I think there are 4 carriers per beam, comprising 3 carriers of 52 Msps plus 1 carrier of 40Msps, making a total used bandwidth of approx 206 MHz.  Total downlink bit rate per spot is 470 Mbit/s clear sky. ( Some say 475 Mbit/s. )

It would be helpful if someone in Beam 3 could measure the visible carriers on a spectrum analyser. Reports of C/N from other customers at other locations in Beam 3 please..

If all carriers in the beam are low level the satellite output amplifier may have degraded and all downlink carriers in that beam have reduced.

Alternatively if all carriers in the beam are low level, the uplink gateway site may be transmitting all the carriers at reduced power or is suffering severe rain or is mispointed.

If just one carrier is low level then this means an adjustment is needed at the Gateway to equalise the carrier levels.

The beam patterns shown above are notional. Only by precise measurements at multiple ground sites can the actual beam positions be determined. The satellite is not fixed to anything and the pattern of beams is aimed at the earth, probably using tracking on a gateway site.

More of my guesswork here http://www.satsig.net/tooway/ka-sat-system-technical.htm

Eric

Title: Re: Tooway SNR RX weakening
Post by Gavarres on Aug 11th, 2019 at 10:10am
Thanks Eric,

My comments to your remarks:
- I have painstakingly readjusted the pointing of the dish.
- The dish is not corroded. I cleaned from dust.
- The horn is ok, no damp, no spiderwebs

I replaced the LNB with another one and this one give the same results of 10 dB.

The degrading went in 4 years time from 11.3 dB to 10.0dB.

Your technical explanation is beyond my knowledge, but I can understand that the output from the satelite could be decreasing. Or that the pointing of the satelite beam is just a tiny bit off as the satelite is geostationary but as you say it is not attached to anything.

When you are in the middle of the beam it does not hurt, but when you are at the edge of a beam, then a tiny offset is noticeable.

I discussed it with the provider and I suggested to get a larger diameter dish (2m). He is now looking for it.

Title: Re: Tooway SNR RX weakening
Post by Gavarres on Aug 18th, 2019 at 5:24pm
A short update:

With the same dish and without doing anything, the signal has improved with about 0.5 dB since a few days. It's now around 10.5 dB.
I wonder if they can reposition the satellite a bit or that they can tweak the beam.

Title: Re: Tooway SNR RX weakening
Post by Gavarres on Aug 21st, 2019 at 7:32am
Update:
By doing NOTHING the signal now is around 11.0 dB. So it is becoming near the old value of 11.3 dB of four years ago.
I am totally puzzled. I guess it's due to the tuning of the beam at the satellite or repositioning of the satellite itself.

I now can 100% be sure it's not due to deterioration of my equipment or due to misalignment of the dish.

Title: Re: Tooway SNR RX weakening
Post by SandFish on Aug 29th, 2019 at 10:13am
I have also had a Tooway system for almost 5 years, in the Adriatic, also on a Blue circle, but fairly central to the circle.

My signal has dropped over time from 13 to 10 ish.  My Croatian supplier is useless refusing to help in any way!

This week I have lost connectivity.  The RX: SNR is constantly fluctuating as I watch, now between 10.5 and 11.1dB.  Yesteday it was between +6dB and -3.5dB.  I looked to see if I had an owl or something roosting on the dish/tria.  I need to do a re-allign I think.

I've bought a SatLink digital meter to try and align the dish better then the http:/.../install command, but something seems to be going on, beyond my home setup!

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