Loss of signal due to rain

A

Archive-10

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Not sure if this is the right place to ask this question, but seems the most logical.
It´s raining " gatos y perros " ( cats and dogs ) here at the moment and most of my UK channels are having problems.
Some are still OK, like Pick for example, but most of the BBC and ITV etc are breaking up, although having gone through a few of them ITV3 and Channel 4+1 seem better than the rest.
Why would that be?
 

Terryl

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The strongest transponders will have a better chance punching through the tons of water vapor in the rain cloud's, most satellite transponders are rated from 20 to 120 watts ERP, if you do a path loss calculation with the distance being 22,500 miles (35,786 kilometers) to a 1 meter dish, you get an estimated loss of over 120 to 140 dBm, it also has to do as to where your dish is in the footprint of the satellite your looking at.

satbeams.com has a footprint lookup by satellite.

The only proven fix for Ku band rain fade is a bigger dish, some have tried rain shields on the LNB, or car wax on the dish, or other type of gimmicks but it wont help if the signals coming down from the satellite have to go through 20,000 feet of heavy rain or heavy water vapor.

The signal hitting your dish is about as weak as looking at candle at 20 miles away, very very weak, in the picovolt range, look at some of the local CATV company's, you will see some very big dishes around,(if they haven't switched to fiber) some are for "C" band, but others are for any Ku band feeds.
 

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Because rain affect signal quality, especially heavy rain, or rain in the line of sight, but not as badly as snow, heavy snow is a killer.
Beaten to it.
 

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wrong section sorry
 
A

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OK, I´m lost!
I understand rain kills the signal, like radio waves in air or water behave differently. But why are some stronger than others?
@Terryl don´t get the wrong section bit?
 

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Satellite signals are microwaves and absorbed by water / water vapour.

As you are in Spain, you will have weaker signals than the UK so have less rainfall resilience to "rain fade"

Different transmission types have more or less resilience too. A dvb signal will last longer than dvb-s2 qpsk signal which in rtrun will last longer than a dvb-s2 8psk signal.
PLUS the forward error correct (fec) has influence - the lower the numbers the better the signal so 2/3 will last longer than 5/6 will last longer than 8/9
 
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A

Archive-10

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OK, I´ll have to take your word on that, re the dvb dvb2 bit, I´ll read up on that.
But why does ITV3 and Channel4+1 stay up better than the others, and where can I check the fec to decide which I should " lose " first?
 

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OK, I´m lost!
I understand rain kills the signal, like radio waves in air or water behave differently. But why are some stronger than others?
@Terryl don´t get the wrong section bit?
I was posting something in a different section of the forum, somehow it wound up in this one, and I could not delete it here for some reason.

And not all transponders have the same output wattage, some transponders are for local regions, city or county spot beams, area wide beams, country wide beams, and others are global. (cover everything that the satellite can see)

And again it all matters on were your located in the footprint, looking at the signals for 28.2 East, here is an active footprint map for those satellites.


You can select a beam/satellite, then zoom into your location, then click on it, it will give you an estimated signal report for your location.
 
A

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I was posting something in a different section of the forum, somehow it wound up in this one, and I could not delete it here for some reason.

And not all transponders have the same output wattage, some transponders are for local regions, city or county spot beams, area wide beams, country wide beams, and others are global. (cover everything that the satellite can see)

And again it all matters on were your located in the footprint, looking at the signals for 28.2 East, here is an active footprint map for those satellites.


You can select a beam/satellite, then zoom into your location, then click on it, it will give you an estimated signal report for your location.
OK , now I understand the crop circle bit!
 

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Well I cannot give an explanation too for the difference in signalstrength for the SD-versions of BBC compared with SD-versions of ITV 3 and Channel 4 +1.
They are both on the same satellite (exept 10994 H), with the same beam (UK beam) and same parameters. The only difference is the frequency.

Code:
ITV 3, 10906 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
Ch4+1, 10936 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6

BBC(SD), 10773 H, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10788 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10803 H, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10818 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
ITV(SD), 10758 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10891 H, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10906 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10994 H, Astra 2G, UK Beam, DVB-S, 22000, 5/6


Pick is on 12070 H on Astra 2E on the Europa beam which has another signalstrength, but should be weaker in your location (!).
Maybe the higher frequency could cause a problem, because of more loss of signal.

Make sure you don't compare SD with the HD versions, because the HD channels use other parameters.
That's comparing "manzanas y naranjas" (apples with oranges).
 
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Well I cannot give an explanation too for the difference in signalstrength for the SD-versions of BBC compared with SD-versions of ITV 3 and Channel 4 +1.
They are both on the same satellite (exept 10994 H), with the same beam (UK beam) and same parameters. The only difference is the frequency.

Code:
ITV 3, 10906 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
Ch4+1, 10936 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6

BBC(SD), 10773 H, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10788 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10803 H, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10818 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
ITV(SD), 10758 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10891 H, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10906 V, Astra 2E, UK Beam, DVB-S, 22000, 5/6
         10994 H, Astra 2G, UK Beam, DVB-S, 22000, 5/6


Pick is on 12070 H on Astra 2E on the Europa beam which has another signalstrength, but should be weaker in your location (!).
Maybe the higher frequency could cause a problem, because of more loss of signal.

Make sure you don't compare SD with the HD versions, because the HD channels use other parameters.
That's comparing "manzanas y naranjas" (apples with oranges).
Thanks for the info, and no need for the translation, been bouncing in and out of Spain long enough to pick up some of the language!
What I don´t understand , but am starting to learn, is that the V frequencies on the " spot " beams appear stronger , why or how I have no idea. Also, 10900 to 10999 seem to be better than the others. Pick on 12070 never goes off, like Sky news, but on the Europe beam.
What I don´t understand is why 10818V has problems when 10936V doesn´t.
 

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But why does ITV3 and Channel4+1 stay up better than the others, and where can I check the fec to decide which I should " lose " first?
Some frequencies and polarisations are slightly better than others in your area of Valencia.
For example BBC 1 West Yorkshire is on a horizontal frequency, and I find this is slightly weaker, and so "goes off" earlier in rain than BBC1 Yorks and Lincs, which is on a vertical frequency. So using an alternate BBC region may help a bit,
In the same way, ITV Scotlands frequencies seem to be slightly "stronger" than other itv regions.
(Not that this helps as ITV23and4 do not have regional variations but of these three itv3 tends to be slightly better than itv2and4)
"What I don´t understand is why 10818V has problems when 10936V doesn´t.
Because there are power variations at the satellite transponder level, and also there are slight differences as you move up along the frequencies...
I find that, on my signal meter, the C4 frequency (10714), tends to be stronger than the BBC 2 frequency 10773, witht he C5 frequency being even stronger, all three on the UK beam and horizontal.
Pick on 12070 never goes off, like Sky news, but on the Europe beam.
Ah but they do and can. Even on my 1.8m dish, in very heavy rain (like torrential rain) they can go off, but then signals in the UK can also go off in extreme rain. But than European beam has a lot better reception than the UK beam (see the signal footprint maps), so they appear stronger...
 

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"Pick on 12070 never goes off, like Sky news, but on the Europe beam."
At my location those are the first to go.
 

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As colleagues indicate, it depends on the power with which they emit the signal and where that signal points.
If we put a stereo 30Watios, it will reach much less than if we have 1000W.
I put an old photo 2016, but valid to tell the same, from Madrid (Spain with 125cm antenna).
Referenced 2 frequencies/tp of the UK beam and the signal difference with the European beam.
Guess riddle, who disappears earlier?
11022-H-11052-H-1.png


For Madrid in good weather/bad weather, the criticism for disappearing, in this order.
11053 sticks with the adjacent tp (beam europe) pending adjust well, OK 8:00-9:30.
11023 threshold fec.
12382 telephone interference.
11068.
11022-H-11052-H-2.png
 

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Not only are there are signal strength variations at the transmission end but they can also be caused by the reception kit - tuners and lnbs can (and do) have peaks and troughs in their sensitivity to different frequencies, cable length between lnb and tuner can also have troughs in signal due to harmonics of reflections (from every joint) causing interference at particular frequencies. With transponders being on multiple satellites it is impossible to accurately align a dish (particularly large ones) for a maximum signal on all satellites amd alignment is always a compromise for optimum reception on all.

Without professional equipment you are highly unlikely to find the reason (or combination of reasons) why your particular system reacts as it does. You can only set up your system for optimum across all required channels
 
A

Archive-10

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Thank you all for the information. Will take me a while for it to sink in so I fully understand it, but guess it´s down to exact location, transmission strength and the kit itself.
 
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