Date   

Re: TP 1 SNR reduction.

James Brown
 

And even as you wrote - another small increase - possibly benefitting eastern stations more than western ones this time? From midday.

Cheers.

James

On 7 May 2021, at 13:47, David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 via groups.io <david-taylor=blueyonder.co.uk@groups.io> wrote:

On 06/05/2021 15:25, geojohnt via groups.io wrote:
Hello All,
I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.
My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.
Regards,
John Tellick.
Folks,

I headlined this in my daily report to EUMETSAT. Previous responses have suggested that as long as the signal is above the minimum agreed level there's no need for action (by EUMETSAT). They are in the hands of their service provider, of course, they don't run the uplink themselves.

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv





Re: TP 1 SNR reduction.

Douglas Deans
 

On 07/05/2021 13:44, David J Taylor GM8ARV 🏴 🇪🇺 via groups.io wrote:
On 06/05/2021 15:25, geojohnt via groups.io wrote:
Hello All,

I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.
My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.

Regards,
John Tellick.
Folks,
I headlined this in my daily report to EUMETSAT.  Previous responses have suggested that as long as the signal is above the minimum agreed level there's no need for action (by EUMETSAT).  They are in the hands of their service provider, of course, they don't run the uplink themselves.
Cheers,
David
============================================================================

Thanks David and I do agree. Nevertheless up here where the signal is more marginal it is annoying that there is an additional 1dB (which I lost yesterday) available. We know the back-up station can provide good improvements for example.

Regards,
Douglas.


Re: TP 1 SNR reduction.

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

On 06/05/2021 15:25, geojohnt via groups.io wrote:
Hello All,
I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.
My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.
Regards,
John Tellick.
Folks,

I headlined this in my daily report to EUMETSAT. Previous responses have suggested that as long as the signal is above the minimum agreed level there's no need for action (by EUMETSAT). They are in the hands of their service provider, of course, they don't run the uplink themselves.

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv


Re: daily cyclic signal change

geojohnt@...
 

Hello Nigel,

I would say that that the diurnal variation we see is more to do with the state of the troposphere and space weather than the figure of 8 movement of our satellites.
When the Sun is on 'our side of the planet' our polarised signals can become slightly twisted as they pass through the various 'excited layers.'

Commercial TV satellites are quite tightly controlled by the satellite operators - but of course their 'movement' is not that important for domestic satellite TV reception with 45 cm receiving dishes - more  important for the service uplinks to the satellite.

Just look at the inclination of MSG-1 and MSG-2 - though they are spin stabilised, not three axis.
They will take some tracking from the ground station control dishs.

On our GEO visits to EUMETSAT we went to the satellite ground station at Ursingen and standing under the giant Meteosat receive/control dishes, they would make a loud clunk every now and again as they tracked the slight movement of the satellite.

You are absolutely right, it's amazing how the geostationary satellite 'stay in the same place.'
One forgets(?) they are actually moving - as the Earth is. 

Regarding our 'dish alignment,' most of us use domestic satellite TV dishes which I would say in their original construction are impossible to align to 100% accuracy.
And as for the Triax 1 m dish - the less said about that, the better.

Several members have designed a sort of Vernier lever system to adjust both elevation and azimuth to very good accuracy.


Regards,
John




-----Original Message-----
From: nigel <nigel@...>
To: MSG-1@groups.io
Sent: Thu, 6 May 2021 8:48
Subject: Re: [MSG-1] daily cyclic signal change

Hi John,
Good to hear from you, also.
Thanks for your thoughts and yes, I am seeing a "diurnal variation" - i.e. the same pattern repeating each day, but I do not know if it is due to the earths rotation or the satellite describing a figure of 8 ( or 0 - thanks for the reminder of your animations, Ernst! ) about its nominal position.
I  hadn't really thought about what is required to keep a geostationary satellite fixed in position, in relation to a location on earth, when we are both spinning in space. My mind boggles at the maths involved, let alone the technology required. Harmut's comment about the saving in fuel really started me thinking !!
As for getting the alignment within 0.5 degree - I would think that must involve a very precise mounting arrangement - not possible with the bog standard commercial setup. I did plan to try and improve my dish's mounting and adjustment system, but that is still at "the design stage".
More googling and research is needed, I'm sure.
Regards
Nigel


On 05/05/2021 17:35, geojohnt via groups.io wrote:
Hello Nigel,

Good to hear from you again.

Firstly TP 1 has been 'doing something' in the last few days.
You will have seen that Ian and I reported a few days ago that our SNR has increased considerably - but it wasn't to last.
Back to normal a day or so later.
Though I did see another brief increase again yesterday afternoon.

By daily variation, do you mean at 'set' times/periods - your graphs appear to show this.
I too have a variation in SNR during the day - diurnal variation - due to that state of the atmosphere/troposphere.
I wrote an article about this for the GEO Quarterly a few years ago.

I always wondered about whether 'we' would see signal variations due to a satellite's figure of 8 movements but dismissed this as the movements were 'very small.'
However looking at EUMETSAT's dish off pointing graphs as posted by Ernst, you can lose 1 dB 'very easily' with an 0.5 degree dish error when using larger dishes.

Goodness, is it possibly to align a dish to 0.5 degree accuracy or less? 

Best wishes,
John.

 

_._,_._,_


EUMETCast Hotbird dissemination test.

geojohnt@...
 

Hello All,

Just a quick first test - swinging my dish further towards the neighbour's fir tree.
I must be right on the edge now.

Using a 1 m dish, Inverto quad Black Ultra LNB, skew adjusted and an SR1 I'm getting SNR 14.4 dB Power -23 dBm as shown by the SR1 Controller display.

I would have expected my SNR to be higher(?) since Hotbird 13 E's power output contour in my location is 5 dBW higher than Eutelsat 10A.

Regards,
John Tellick.



Re: TP 1 SNR reduction.

nigel
 

On 06/05/2021 17:29, Hartmut Schulla via groups.io wrote:

Hi!

Same here! Drop of approx. -1.2dB

day

Regards

Hartmut

 

Von: MSG-1@groups.io <MSG-1@groups.io> Im Auftrag von geojohnt via groups.io
Gesendet: Donnerstag, 6. Mai 2021 16:26
An: msg-1@groups.io
Betreff: [MSG-1] TP 1 SNR reduction.

 

Hello All,

 

I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.

My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.

 

Regards,

John Tellick.

 

 

 

 


Re: TP 1 SNR reduction.

geojohnt@...
 

Hello Hartmut,

Yes.
My SNR is down at least 1 dB but there is a weather front going over at the moment.

I've reported this to EUMETSAT.

Regards,
John.




-----Original Message-----
From: Hartmut Schulla via groups.io <mail@...>
To: MSG-1@groups.io <MSG-1@groups.io>
Sent: Thu, 6 May 2021 15:29
Subject: Re: [MSG-1] TP 1 SNR reduction.

Hi!
Same here! Drop of approx. -1.2dB
day
Regards
Hartmut
 
Von: MSG-1@groups.io <MSG-1@groups.io> Im Auftrag von geojohnt via groups.io
Gesendet: Donnerstag, 6. Mai 2021 16:26
An: msg-1@groups.io
Betreff: [MSG-1] TP 1 SNR reduction.
 
Hello All,
 
I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.
My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.
 
Regards,
John Tellick.
 
 
 
 


Re: TP 1 SNR reduction.

Hartmut Schulla
 

Hi!

Same here! Drop of approx. -1.2dB

day

Regards

Hartmut

 

Von: MSG-1@groups.io <MSG-1@groups.io> Im Auftrag von geojohnt via groups.io
Gesendet: Donnerstag, 6. Mai 2021 16:26
An: msg-1@groups.io
Betreff: [MSG-1] TP 1 SNR reduction.

 

Hello All,

 

I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.

My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.

 

Regards,

John Tellick.

 

 

 

 


TP 1 SNR reduction.

geojohnt@...
 

Hello All,

I see from my own readings and David's across Europe signal graphs that most of us have seen a step drop in SNR/LM at 13:00 UTC today.
My SNR is down from 13.5 this morning to around 12.5 dB with some cloud now.

Regards,
John Tellick.





Re: SR1 changing receiving channel?

geojohnt@...
 

Hello Ernst,

Oh, of course, thanks.

It's just how to re-configure the SR1 - there seems to be no guide as to changing the set up - like 'do this, then this and then this.
If you see what I mean as the SR1 came setup for the current - original - EUMETCast configuration.

Regards,
John




-----Original Message-----
From: Ernst Lobsiger via groups.io <ernst.lobsiger@...>
To: MSG-1@groups.io
Sent: Wed, 5 May 2021 17:49
Subject: Re: [MSG-1] SR1 changing receiving channel?

On Wed, May 5, 2021 at 09:08 AM, <geojohnt@...> wrote:

Polarisation requires changing but the SR1 doesn't have a H/V 'switch' in configuration.
John,


polarisation is switched by LNB voltage (power) applied:

H = 18 Volt
V = 13 Volt

Ernst



Re: Request for advice: dish wobbling in the wind, alignment & signal quality

J.W. Davies
 

Please let us know how you eventually solve your problem.

Your real life experience may be of use to others in a similar situation.


Regards

James

On 06/05/21 08:38, Peter Novak wrote:
Thanks James. Your ideas are also very useful. I found a
mechanical engineer in my close network I will ask him to translate your
and Ernst's ideas into a concrete advice at our site.

I appreciate your help.

Best,

Peter.

On Wed, May 05, 2021 at 09:26:29PM +0100, J.W. Davies wrote:

I agree with Ernst that there is significant wind resonance effects
there. The dish is clearly too flimsy for the windy location.

However, a few things you may wish to try:-

I notice the feed arm has significant movement and this is probably the
source of the biggest impact on signal strength. The position of the LNB
at the focus is very critical.

There is an old trick from the days of Band 1 television where the
hollow aerial elements had a length of rope inserted during manufacture
to dampen wind resonance.
It looks like the LNB feed arm is hollow. So you could try inserting a
piece of rope, tightly fitting in the length of the arm to dampen it.

I agree with the comments of others that the mast is rather weak.
Its not clear how much that is moving from the video but that could also
be packed with pieces of ropes to stiffen and dampen.
If it is blocked at the bottom then even filling it with sand may help.

The flimsy reflector is more problematic. If needed after trying the
above, one possibility is to strengthen the back by applying fibreglass
matting and resin to build up the thickness. The surface being “keyed”
by roughing it with carborundum/ sand  paper first.

The possibility of shielding the back and sides with wooden/plastic
panelling, as a windbreak,  say about 1.5 Metres high, may be another
possibility. The panelling should not be a solid wall as you will get
turbulence downwind, making the situation worse. The panelling should
have gaps in it to make it permeable to the wind, slowing the wind
rather than  stopping it.

Whether its worth the effort is another question and getting a stronger
dish such as the Gibertini OP 125 L may be less hassle.

Regards
James




Re: daily cyclic signal change

nigel
 

Hi John,

Good to hear from you, also.

Thanks for your thoughts and yes, I am seeing a "diurnal variation" - i.e. the same pattern repeating each day, but I do not know if it is due to the earths rotation or the satellite describing a figure of 8 ( or 0 - thanks for the reminder of your animations, Ernst! ) about its nominal position.

I  hadn't really thought about what is required to keep a geostationary satellite fixed in position, in relation to a location on earth, when we are both spinning in space. My mind boggles at the maths involved, let alone the technology required. Harmut's comment about the saving in fuel really started me thinking !!

As for getting the alignment within 0.5 degree - I would think that must involve a very precise mounting arrangement - not possible with the bog standard commercial setup. I did plan to try and improve my dish's mounting and adjustment system, but that is still at "the design stage".

More googling and research is needed, I'm sure.

Regards

Nigel



On 05/05/2021 17:35, geojohnt via groups.io wrote:
Hello Nigel,

Good to hear from you again.

Firstly TP 1 has been 'doing something' in the last few days.
You will have seen that Ian and I reported a few days ago that our SNR has increased considerably - but it wasn't to last.
Back to normal a day or so later.
Though I did see another brief increase again yesterday afternoon.

By daily variation, do you mean at 'set' times/periods - your graphs appear to show this.
I too have a variation in SNR during the day - diurnal variation - due to that state of the atmosphere/troposphere.
I wrote an article about this for the GEO Quarterly a few years ago.

I always wondered about whether 'we' would see signal variations due to a satellite's figure of 8 movements but dismissed this as the movements were 'very small.'
However looking at EUMETSAT's dish off pointing graphs as posted by Ernst, you can lose 1 dB 'very easily' with an 0.5 degree dish error when using larger dishes.

Goodness, is it possibly to align a dish to 0.5 degree accuracy or less? 

Best wishes,
John.

 

 




-----Original Message-----
From: nigel <nigel@...>
To: MSG-1@groups.io
Sent: Wed, 5 May 2021 14:00
Subject: [MSG-1] daily cyclic signal change

Hi Folks,
for a long time now, I have been seeing a daily variation in my received signal. I have been told that it was probably due to a slight misalignment of my ground mounted 1.5 Metre prime focus dish.
The stations location is North Cyprus ( 35.36 N, 33.03 E ) at an elevation of about 100 Metre.
MRTG graphs, showing these variations can be seen here :- http://www.nigelheasman.com/mrtg/SR1/inwin_mrtg_sr1.html
I have tried several times to improve the alignment, following various folks methods and now feel it is the best I can achieve. But, the cyclic variations continue !
The link margins are good enough to enable me to receive the Basic Service as well as High Volume Service 1, so I am happy with the result ( until my dogs crash into it and upset the alignment ! ) BUT I am intrigued by this variation and wondering if the magnitude and/or timing of the peaks and troughs can give a clue as to which part of the alignment could be improved?
Does anyone have any ideas or suggestions, please?
Looking forward to reading any comments!
Thanks
Nigel


Re: Request for advice: dish wobbling in the wind, alignment & signal quality

Peter Novak
 

Thanks James. Your ideas are also very useful. I found a
mechanical engineer in my close network I will ask him to translate your
and Ernst's ideas into a concrete advice at our site.

I appreciate your help.

Best,

Peter.

On Wed, May 05, 2021 at 09:26:29PM +0100, J.W. Davies wrote:

I agree with Ernst that there is significant wind resonance effects
there. The dish is clearly too flimsy for the windy location.

However, a few things you may wish to try:-

I notice the feed arm has significant movement and this is probably the
source of the biggest impact on signal strength. The position of the LNB
at the focus is very critical.

There is an old trick from the days of Band 1 television where the
hollow aerial elements had a length of rope inserted during manufacture
to dampen wind resonance.
It looks like the LNB feed arm is hollow. So you could try inserting a
piece of rope, tightly fitting in the length of the arm to dampen it.

I agree with the comments of others that the mast is rather weak.
Its not clear how much that is moving from the video but that could also
be packed with pieces of ropes to stiffen and dampen.
If it is blocked at the bottom then even filling it with sand may help.

The flimsy reflector is more problematic. If needed after trying the
above, one possibility is to strengthen the back by applying fibreglass
matting and resin to build up the thickness. The surface being “keyed”
by roughing it with carborundum/ sand  paper first.

The possibility of shielding the back and sides with wooden/plastic
panelling, as a windbreak,  say about 1.5 Metres high, may be another
possibility. The panelling should not be a solid wall as you will get
turbulence downwind, making the situation worse. The panelling should
have gaps in it to make it permeable to the wind, slowing the wind
rather than  stopping it.

Whether its worth the effort is another question and getting a stronger
dish such as the Gibertini OP 125 L may be less hassle.

Regards
James


Re: Request for advice: dish wobbling in the wind, alignment & signal quality

J.W. Davies
 

I agree with Ernst that there is significant wind resonance effects
there. The dish is clearly too flimsy for the windy location.

However, a few things you may wish to try:-

I notice the feed arm has significant movement and this is probably the
source of the biggest impact on signal strength. The position of the LNB
at the focus is very critical.

There is an old trick from the days of Band 1 television where the
hollow aerial elements had a length of rope inserted during manufacture
to dampen wind resonance.
It looks like the LNB feed arm is hollow. So you could try inserting a
piece of rope, tightly fitting in the length of the arm to dampen it.

I agree with the comments of others that the mast is rather weak.
Its not clear how much that is moving from the video but that could also
be packed with pieces of ropes to stiffen and dampen.
If it is blocked at the bottom then even filling it with sand may help.

The flimsy reflector is more problematic. If needed after trying the
above, one possibility is to strengthen the back by applying fibreglass
matting and resin to build up the thickness. The surface being “keyed”
by roughing it with carborundum/ sand  paper first.

The possibility of shielding the back and sides with wooden/plastic
panelling, as a windbreak,  say about 1.5 Metres high, may be another
possibility. The panelling should not be a solid wall as you will get
turbulence downwind, making the situation worse. The panelling should
have gaps in it to make it permeable to the wind, slowing the wind
rather than  stopping it.

Whether its worth the effort is another question and getting a stronger
dish such as the Gibertini OP 125 L may be less hassle.

Regards
James

On 05/05/21 09:17, Peter Novak wrote:
Dear group,
we have installed a 120cm satellite dish on a roof of an office building
at a relatively exposed location near the sea coast in the Netherlands.
Things work quite fine, in good weather conditions our signal strength
is at -25/-26dBm and Es/No at 13.0-13.5dB with solid link margins for
both BAS (~7.4dB), as well as HVS (~3.6dB). We are receiving HVS stream
data. That's all fine and well. However, in more windy conditions the
dish wobbles quite a lot (easily by 2-4cm at the top), which in turn
leads to misalignments, occasional loss of lock and subsequent loss of
received files. As an example, I made a short video of the dish moving
in 6 Bft wind here: https://owncloud.hq.meandair.com/s/Zo3mKIsiRk9ByG5

I wonder what solutions other group members are using to mitigate this
problem. I looked at some metal support arms/struts which would affix
the dish sides to the mast better than now, but I don't even know how
are such products called.

I would appreciate any advice, or pointers to improvements of the setup
to mitigate the misalignments in windy conditions we are experiencing.

Thanks a lot for your advice.

Best regards,

Peter.







Re: daily cyclic signal change

Ernst Lobsiger
 

On Wed, May 5, 2021 at 08:36 AM, David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 wrote:
Yes, I mentioned that to Nigel when he first asked.
All

after my "Old Farts" blackout moment I went for a walk and some fresh air. Here is what we did in 2017.
Figure 8 of EUTELSAT E10A actually turned out to be a Figure 0!! I found and copied all the files and
calculations including animated gifs for Edinburg, Kaylar and the E10A sub satellite point SSP on Luna:

http://5.153.116.236:86

You will still find some of our discussions in threads "Figure 8" and/or "Figure 8 revisited" on this list.

Cheers,
Ernst


Re: Request for advice: dish wobbling in the wind, alignment & signal quality

Ernst Lobsiger
 

On Wed, May 5, 2021 at 09:57 AM, Peter Novak wrote:
That's indeed what I understand from your comment above. Just to
understand it clearly. It seems you think that large part of the problem
is actually the mast bending like a spring and the dish contributes only
in part. Is that correct?
Peter,

I didn't see the second layer of your concrete plates. In any case you should
expect forces of >=500 N (>= 50 kp) in 120 km/h gusts on the mast clamps. At
some place of the video it even looks as if the plates are lifted (may not be real).

From the video it's rather hard to see how much is twisting of the mast tube and
how much is actually bending of the SAB steel dish itself. The Gibertini OP 125L
is sold as 1mm steel dish but also as 1.5mm aluminum dish. Aluminum is rather
ductile and cannot work as a spring. My idea of introducing some attenuation
to the "eigenfrequency" assumed that the bending of the dish is essential.

Youssef has a good point as well. The video starts with showing a vertial
edge of a huge red and close building. This can produce heavy turbulence.
But as you said moving the dish somewhere to a calm place is not possible.

It's certainly a good idea to let a mechanical engineer or physicist have a look.

Regards,
Ernst


Re: Request for advice: dish wobbling in the wind, alignment & signal quality

Peter Novak
 

Thanks Youssef for your response. Those images from simulations make
sense indeed. Unfortunately, for now, repositioning at our site is not
really an option, we are limited by a high rise building to the
south-east from our place. But yes, one thing we are looking at is to
move the whole setup to a different location completely. By now it's
clear that closer to the ground could be actually safer than the 5th
floor we are.

Thanks again for your help.

Best,

Peter.

On Wed, May 05, 2021 at 02:48:48PM -0000, Youssef Bennouna wrote:

Peter,
It's an important issue for most amateurs as they generally put their
satellite dishes on top of the roof. The wind patterns on the roof are not
the same as an open field, in some places, the winds are stronger and weaker
in others. The wind strength, gusts, and turbulence vary from place to place
on the roof. It depends on many factors like the height of the building, the
existence and height of neighboring buildings, the direction of the dominant
wind...local winds are not the same as those measured by a weather station.
A better assessment of local conditions is necessary before choosing the
right location for the dish, taking into account of course other factors
like cable distance, clear view of the satellite etc.
Here are some pictures showing wind distribution patterns around and over
buildings (from CFD study, comments are in French). This might help you
figure out a better place for your dish and avoid very installing heavy
mechanical duty to stabilize it.
I hope this will help.
Best regards


Youssef Bennouna
ETUDES ET MESURES LES 5 DOMAINES


Re: Request for advice: dish wobbling in the wind, alignment & signal quality

Peter Novak
 

Hello Ernst, group,
thanks a for your response. It's indeed very useful and informative.

I looked up the mechanical specs of your SAB Satellite (S120/M120) dish here:

https://www.sabsatellite.nl/upload/files/1452181362-SAB%202014%20dishes.pdf

It's 108.2 x 120.6cm in 0.9mm steel. Mast diameter possible 34 - 60mm.

Already the mast diameter span is close to unacceptable for a 120cm dish.
It's 42mm diameter, 2mm steel. From your comment I understand a thicker
one would be better. That is indeed an option.

In fact, we originally designed the setup for a 96cm dish, but that
turned out to produce too weak signal, so we replaced it later on
without changing the mast, hence the diameter.

Also the long pillar for the LNB does not look very stable for a 120cm dish.
Stabilisation of the arm seems like a good idea too.

Your problem seems to be a resonance effect with the natural
mechanical oscillation frequency of the dish. The steel material works
like a spring with little attenuation and the frequency is low because
the M120 mount is not wide enough.
Thanks. That makes sense indeed. Regarding the not enough wide mount you
mean the mast diameter, or generally construction of the dish mount at
the back of it?

I attach two images of my dish. Please note the stable construction of
the LNB support. But also note the mass of concrete plates used to
keep my homebrew tripod struts on the ground. YOUR CONSTRUCTION LOOKS
TOO LIGHTWEIGHT FOR A 120cm DISH!
Those are 2 layers of 4 concrete tiles, each 22.5kg heavy. That makes
180kg anchor weight on the flat roof stand construction. Do you think
it's not enough? I mean, another layer of tiles would make +90kg, that's
easy to do, but will it help?

2) Try to stabilize the dish with 4 aluminum stripe struts to the pole.
The downside is this makes repointing close to mission impossible.
Also it's possible that the dish can be distorted by temperature effects.
We had something like that in mind indeed. It seems this is indeed the
factor which would help most.

4) You can bring down the natural oscillation frequency by attaching left
and right a 1kg screw clamp to the brim (on your own risk and peril!).
As a quick fix that might be a good idea too. From your comments, I also
understand that I need to speak to a mechanical engineer for advice - I
am a software guy :-).

5) Buy a more professional dish and a solid/heavy 80mm mast construction.
That's indeed what I understand from your comment above. Just to
understand it clearly. It seems you think that large part of the problem
is actually the mast bending like a spring and the dish contributes only
in part. Is that correct?

Actually, another idea could be to weld a tripod structure between the
mast top and the stand below similarly as you have it on the high pole
you have there.

Also, I checked out the Gibertini dish you mentioned, but I see it's
also steel material of 1mm thickness, while the one we use is 0.9mm.
Does it make a difference? Apart from a better connected arm, could you
please explain how is that Gibertini dish actually significantly better
than the one we have? As I said, I am not a mechanical engineer, so I am
learning along the way here. To my layman eyes, these are bent metal
plates one like the other :-).

Thanks a lot for your help, I really appreciate.

Best,

Peter.


Re: SR1 changing receiving channel?

Ernst Lobsiger
 

On Wed, May 5, 2021 at 09:08 AM, <geojohnt@...> wrote:
Polarisation requires changing but the SR1 doesn't have a H/V 'switch' in configuration.
John,

polarisation is switched by LNB voltage (power) applied:

H = 18 Volt
V = 13 Volt

Ernst



Re: SR1 changing receiving channel?

geojohnt@...
 

David,

Thanks for your comments.
Yes, I did a preliminary check a couple of months ago thinking I might just get a bit of HB signal in my beamwidth without moving my 1 m dish - but not so.
I had to shift it.

Being a satellite TV guy, I'm used to setting the actual satellite Ku-Band transmission frequency on a receiver.
SR1 and EUMETSAT use the LNB downconverted frequency to tune the receiver.
Not a problem as EUMETSAT detail that on their website test guide.

The frequency requires changing - that seems possible in configuration mode by typing in the new frequency.
Polarisation requires changing but the SR1 doesn't have a H/V 'switch' in configuration.

Also I notice, currently on EUMETCast 10 A, C. Encapsulation is MPEG-TS

On EUMETCast Hotbird the Encapsulation is BS 8PSK3/5 MPE TS, ISI=1

HVS-1 16APSK2/3 MPE TS, ISI=1

???

Regards,
John

++++++++++++++++++++

John,


I think it's just polarisation and frequency.  I took a look with my
TBS5925 and BDADataEx and saw nothing, but that's without moving the
dish, so not surprising.

Cheers,
David
--
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: david-taylor@...
Twitter: @gm8arv


-----Original Message-----
From: David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 via groups.io <david-taylor@...>
To: MSG-1@groups.io
Sent: Wed, 5 May 2021 16:36
Subject: Re: [MSG-1] SR1 changing receiving channel?

On 05/05/2021 16:09, geojohnt via groups.io wrote:

> Hello All,
>
> I want to check the EUMETCast back-up satellite test dissemination from
> Hotbird.
> Could someone please tell me - in step by step, and for me, idiot proof
> ways how to change/configure the SR1 via Telnet to the new frequency and
> polarisation?
>
> Many thanks,
> John Tellick.






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