Topics

SR1 configuration.


geojohnt@...
 

Hello All,

I've been looking at my SR1's status via Telnet and see that the/my Roll Off, # F is set to 25%.

Having been reading the EUMETSAT guide to setting up an SR1 for something else, I see that 
their Roll off is set to 20%

So, does this matter?
Does it make any difference?

BTW, I've no idea what Roll Off is.

Regards,
John Tellick.

  


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

Hello All,

I've been looking at my SR1's status via Telnet and see that the/my Roll Off, # F is set to 25%.

Having been reading the EUMETSAT guide to setting up an SR1 for something else, I see that
their Roll off is set to 20%

So, does this matter?
Does it make any difference?

BTW, I've no idea what Roll Off is.

Regards,
John Tellick.
=======================================

John,

I think it's the sharpness of the filtering. I suspect that (a) the receiver should be the same as or slightly greater than the transmitter (to ensure that all the transmitted bandwidth is received) and that (b) there will be very little difference in practice between 20% and 25%.

I recall asking EUMETSAT the same question many years back and getting a similar response.

Of course, if anyone has better information, do please inform us.

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


Ernst Lobsiger
 

On Wed, Jul 1, 2020 at 09:02 AM, <geojohnt@...> wrote:
So, does this matter?
Does it make any difference?
 
BTW, I've no idea what Roll Off is.
 
John

RollOff means how steep the bandwidth filter prevents from interference by close transponders.
20% is somewhat better (sharper) than 25% but you will probably not see any difference such
as increased power and less lost packets. Originally EUMETSAT was talking about 5% RollOff but
only (Non Standard HW, AFAIK 20% is best for DVB-S2) NewTec receivers can possibly do that.

Regards,
Ernst


Ernst Lobsiger
 

On Wed, Jul 1, 2020 at 09:37 AM, David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 wrote:
Of course, if anyone has better information, do please inform us.
David

Sorry, our posts crossed. Here is a link from NewTec that shows their (5%) Clean Channel Technology

https://www.youtube.com/watch?v=VAcO2YezfZg

AFAIK this was used from DVB-S2 day one in EUMETCast Uplinks and professional NewTec receivers.
DVB-S2X will allow for sharper bandwidth filtering than current DVB-S2 (problem as always is drivers!).

Ernst


David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

On Wed, Jul 1, 2020 at 09:37 AM, David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 wrote:
Of course, if anyone has better information, do please inform us.David

Sorry, our posts crossed. Here is a link from NewTec that shows their (5%) Clean Channel Technology

https://www.youtube.com/watch?v=VAcO2YezfZg

AFAIK this was used from DVB-S2 day one in EUMETCast Uplinks and professional NewTec receivers.
DVB-S2X will allow for sharper bandwidth filtering than current DVB-S2 (problem as always is drivers!).

Ernst
==============================

Ernst,

No problem - it's better to have two explanations than one, especially when they explain things from a different point of view.

Thanks for the NewTec link. With filtering being digital these days, and with chip power ever increasing (more ops per second) I imagine getting sharper filtering may not be too difficult. More power from the satellite is something that many enthusiasts would welcome, though!

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


geojohnt@...
 

David,

Ah, of course, I remember now, something to do with bandwidth.

Thanks for your comments.

Regards,
John.

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

John,


I think it's the sharpness of the filtering.  I suspect that (a) the 
receiver should be the same as or slightly greater than the transmitter (to 
ensure that all the transmitted bandwidth is received) and that (b) there 
will be very little difference in practice between 20% and 25%.

I recall asking EUMETSAT the same question many years back and getting a 
similar response.

Of course, if anyone has better information, do please inform us.

Cheers,
David
-- 

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

-----Original Message-----
From: David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺 via groups.io <david-taylor@...>
To: msg-1@groups.io
Sent: Wed, 1 Jul 2020 17:34
Subject: Re: [MSG-1] SR1 configuration.

Hello All,

I've been looking at my SR1's status via Telnet and see that the/my Roll
Off, # F is set to 25%.

Having been reading the EUMETSAT guide to setting up an SR1 for something
else, I see that
their Roll off is set to 20%

So, does this matter?
Does it make any difference?

BTW, I've no idea what Roll Off is.

Regards,
John Tellick.
=======================================



geojohnt@...
 

Ernst,

Thanks for the information.

And for your further email link regarding NewTec receivers - interesting.

>https://www.youtube.com/watch?v=VAcO2YezfZg

>AFAIK this was used from DVB-S2 day one in EUMETCast Uplinks and professional NewTec >receivers.
>DVB-S2X will allow for sharper bandwidth filtering than current DVB-S2 (problem as always is >drivers!).

Regards,
John.

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

-----Original Message-----
From: Ernst Lobsiger via groups.io <ernst.lobsiger@...>
To: MSG-1@groups.io
Sent: Wed, 1 Jul 2020 17:44
Subject: Re: [MSG-1] SR1 configuration.

On Wed, Jul 1, 2020 at 09:02 AM, <geojohnt@...> wrote:
So, does this matter?
Does it make any difference?
 
BTW, I've no idea what Roll Off is.
 
John

RollOff means how steep the bandwidth filter prevents from interference by close transponders.
20% is somewhat better (sharper) than 25% but you will probably not see any difference such
as increased power and less lost packets. Originally EUMETSAT was talking about 5% RollOff but
only (Non Standard HW, AFAIK 20% is best for DVB-S2) NewTec receivers can possibly do that.


Regards,

Ernst