Hi All,

here is all possible images you get from three slots of seviri files (most automatically abbreviated composite names, original composite names in filenames).

https://we.tl/t-JfzqNvVB7O


SatPy 0.35, built in composites only. With above link you get a test.zip of  373 MB  (NO typo !!) from "wetransfer". All *.jpg images generated with one script.

Cheers,
Ernst

P.S. The link stays active 1 week starting with the date of this post.

Hi All,

here is all possible images you get from three slots of seviri files (most automatically abbreviated composite names, original composite names in filenames).

https://we.tl/t-JfzqNvVB7O


SatPy 0.35, built in composites only. With above link you get a test.zip of  373 MB  (NO typo !!) from "wetransfer". All *.jpg images generated with one script.

Cheers,
Ernst

P.S. The link stays active 1 week starting with the date of this post.

Robert,

sorry to read about your TelliCast reception problems on this and other lists. I cannot know how professional your engineer really was but read this story:

https://groups.io/g/MSG-1/topic/86929967#32153

Even if you cannot climb to your antenna anymore there are a couple of things you can still check with your PC or with simple experiments from the ground nearby.
First of all you *must* know whether or not your location (AFAIK northern exposed slope) is as bad as you seem to think. Some of the best tools you can use are:

https://www.dishpointer.com/

https://www.dishpointer.eu/

If you are still not sure about a blocking tree/wood simple tools like a spirit level and a card board triangle with your antenna elevation could answer this question.
Another approach that just came to my mind is just looking where the sun is at the time of a solar outage (unfortunately spring is over, next outage will be in fall).

https://groups.io/g/MSG-1/message/31997

Finally rests the question: What was your best SNR you ever had on your TelliCast receiver and why is it now -- as far as I understand -- very much lower?

Regards,
Ernst

Robert,

sorry I have to say that for me this clarifies nothing. How can you talk about 12-14dB SNR before the storm and accept
6.5dB SNR now? Unless you have some HF problems (LNB, cable or damaged TelliCast receiver) this is only possible if:

a) The storm moved a tree in front of the antenna or
b) The storm bent and damaged the antenna or
c) The storm simply misaligned your antenna

To point a 1m parabolic dish (in azimuth) a compass is worth close to nothing !
It might just help to roughly check the line of sight together with the inclinometer.

To point the dish in elevation there should be some scale on the mount.
Then point in azimuth using the sun. This has been described a couple of times.
Finally you must organize some life display of the SNR of your receiver when fine adjusting.

Maybe there is a younger experienced EUMETCast amateur near you that can give you a hand.

Best regards,
Ernst

Sorry Ernst – I use the compass and inclinometer to check the skyline for obstructions (I only have a very small slot to see the satellite). The lining up of the dish was done by maximising the signal strength. We spent – quite literally – hours, over three days, getting the maximum signal, with the engineer and his meter up the ladder. The position was highly sensitive, a couple of millimetres in azimuth and the signal dropped out altogether. The SNR of 6.2 seemed to me to be absurdly low and I’m amazed that I’m getting any data at all. I have a new 1 metre dish, a new LNB (and a second one when we wondered if the first new one was at fault) and all new cabling.

My theory runs as follows: I had been getting perfect reception for some time, the storm damaged my dish and I lost signal, this happened in winter. By the time we tried re-establishing reception the trees had grown by a few critical centimetres and were in leaf, and so the tops of the trees are now in line with the satellite. Thus, had there been no damage to my fully functioning setup I would have lost signal in the Spring anyhow.

David’s first question was always ‘What has changed?’ The only change is that the trees have grown. After maximising the signal at 6.2 SNR I thought I was out of satellite reception for good and had turned my equipment off. I turned on again recently in a period of windless weather, expecting to confirm that I was finished. So, I was surprised to find I had _some_ reception, near perfect MSG-4 and RSS.

I will wait to see what happens when the wind starts moving the tree-tops again, I suspect the signal will be interrupted. This would confirm my theory and I will, with great regret, dismantle my setup.

It would be great to be wrong!

 

Robert

 

 

From: MSG-1@groups.io <MSG-1@groups.io> On Behalf Of Ernst Lobsiger via groups.io
Sent: 13 June 2022 22:47
To: MSG-1@groups.io
Subject: Re: [MSG-1] All you get from MSG4 seviri with PyTROLL/SatPy out of the box

 

Robert,

sorry I have to say that for me this clarifies nothing. How can you talk about 12-14dB SNR before the storm and accept
6.5dB SNR now? Unless you have some HF problems (LNB, cable or damaged TelliCast receiver) this is only possible if:

a) The storm moved a tree in front of the antenna or
b) The storm bent and damaged the antenna or
c) The storm simply misaligned your antenna

To point a 1m parabolic dish (in azimuth) a compass is worth close to nothing !
It might just help to roughly check the line of sight together with the inclinometer.

To point the dish in elevation there should be some scale on the mount.
Then point in azimuth using the sun. This has been described a couple of times.
Finally you must organize some life display of the SNR of your receiver when fine adjusting.

Maybe there is a younger experienced EUMETCast amateur near you that can give you a hand.

Best regards,
Ernst

Can I make a comment.

You should never try and optimise a satellite system on maximum signal strength. It should be optimised only on maximum Signal to Noise ratio (S/N).

The reason is that any object on the ground is at around 280K. A black body radiator at that temperature (which we can consider things on the ground to be, to a first approximation) radiate significant microwave energy compared to the satellite signal strength.

So  a couple of “hot” leaves on a tree branch, in the dish field of view, will lower the S/N significantly or even obliterate the required signal.

Having, many moons ago, being involved in the development and installation of satellite systems I have seen it in practice on a number of occasions.

A simple test you can do to test this is connect a LNB (no dish) to a signal strength meter. Point the LNB straight up. It sees the (very roughly) 4K of space. Note the signal strength. Then point the LNB straight down so it only sees the (approximately) 280K of the ”hot” ground. You should see a significant increase in signal strength. On a  typical satellite TV system the AGC rail goes from one extreme to the other. The received “hot” ground signal is that strong.

Its a good way to test if an LNB is working.

Hence the importance of having the LNB properly set up on the dish, so that it can’t see the “hot” ground behind. Equally, there is roughly a 1 Metre “tube extending up from your dish that nothing at ground temperature, e.g leaves and branches)  must enter or they will compete with the satellite signal.

It sounds as if in your case the dish, in being aligned for maximum signal strength, it has been aligned for the situation of seeing both the radiating satellite and the radiating leaves. Hence the maximum signal strength!

Sorry Ernst – I use the compass and inclinometer to check the skyline for obstructions (I only have a very small slot to see the satellite). The lining up of the dish was done by maximising the signal strength. We spent – quite literally – hours, over three days, getting the maximum signal, with the engineer and his meter up the ladder. The position was highly sensitive, a couple of millimetres in azimuth and the signal dropped out altogether. The SNR of 6.2 seemed to me to be absurdly low and I’m amazed that I’m getting any data at all. I have a new 1 metre dish, a new LNB (and a second one when we wondered if the first new one was at fault) and all new cabling.

My theory runs as follows: I had been getting perfect reception for some time, the storm damaged my dish and I lost signal, this happened in winter. By the time we tried re-establishing reception the trees had grown by a few critical centimetres and were in leaf, and so the tops of the trees are now in line with the satellite. Thus, had there been no damage to my fully functioning setup I would have lost signal in the Spring anyhow.

David’s first question was always ‘What has changed?’ The only change is that the trees have grown. After maximising the signal at 6.2 SNR I thought I was out of satellite reception for good and had turned my equipment off. I turned on again recently in a period of windless weather, expecting to confirm that I was finished. So, I was surprised to find I had _some_ reception, near perfect MSG-4 and RSS.

I will wait to see what happens when the wind starts moving the tree-tops again, I suspect the signal will be interrupted. This would confirm my theory and I will, with great regret, dismantle my setup.

It would be great to be wrong!

 

Robert

 

 

From: MSG-1@groups.io <MSG-1@groups.io> On Behalf Of Ernst Lobsiger via groups.io
Sent: 13 June 2022 22:47
To: MSG-1@groups.io
Subject: Re: [MSG-1] All you get from MSG4 seviri with PyTROLL/SatPy out of the box

 

Robert,

sorry I have to say that for me this clarifies nothing. How can you talk about 12-14dB SNR before the storm and accept
6.5dB SNR now? Unless you have some HF problems (LNB, cable or damaged TelliCast receiver) this is only possible if:

a) The storm moved a tree in front of the antenna or
b) The storm bent and damaged the antenna or
c) The storm simply misaligned your antenna

To point a 1m parabolic dish (in azimuth) a compass is worth close to nothing !
It might just help to roughly check the line of sight together with the inclinometer.

To point the dish in elevation there should be some scale on the mount.
Then point in azimuth using the sun. This has been described a couple of times.
Finally you must organize some life display of the SNR of your receiver when fine adjusting.

Maybe there is a younger experienced EUMETCast amateur near you that can give you a hand.

Best regards,
Ernst

Hi All,

Metop has some "hidden" or at least rarely used composites as well:
Here is 'green_snow' in Newzeeland (must be winter down there ;-).

Cheers,
Ernst