Topics

Realtime co-lin outage map for your location.

geojohnt@...
 

All,

My spring outage period has started and I've found this realtime map of the 'outage area.'
It updates on a timescale that you select and shows the outage area crossing 'your' location.
In our case parts of Europe.

www.satellite-calculations.com

https://www.satellite-calculations.com/Satellite/sunoutagestatusconfigurator.php

Quite interesting?

Regards,
John Tellick.




David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

Nice one, John!

For those with registered WXtrack, you can get the results in a tabular format.

https://www.satsignal.eu/software/wxtrack.htm

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

geojohnt@...
 

David,

Yes of course, and I have always used this WXtrack function.

But, even with a 1 m dish I find that the co-lin begins before the 'begin' in the list noted and lasts 
longer than the end prediction.
Especially if I recall correctly, around the max Closest.

I subtract 4 then 4 minutes from the predicted Peak - and likewise add 4 minutes plus 4 minutes to 
the Peak - giving me 4 degree beamwidth.
My drop in CN being longer (starting earlier and ending later) than the prediction.

I had a tweak of my dish yesterday after co-lin just to check the dish was - as far as possible - 'aligned.'
It appeared so.

It seems at times that tweaking can be counter productive?  

Regards,
John

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

-----Original Message-----
From: David J Taylor via Groups.Io <david-taylor@...>
To: msg-1 <msg-1@groups.io>
Sent: Wed, 26 Feb 2020 14:08
Subject: Re: [MSG-1] Realtime co-lin outage map for your location.

Nice one, John!

For those with registered WXtrack, you can get the results in a tabular
format.

  https://www.satsignal.eu/software/wxtrack.htm

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




David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

David,

Yes of course, and I have always used this WXtrack function.

But, even with a 1 m dish I find that the co-lin begins before the 'begin' in the list noted and lasts
longer than the end prediction.
Especially if I recall correctly, around the max Closest.

I subtract 4 then 4 minutes from the predicted Peak - and likewise add 4 minutes plus 4 minutes to
the Peak - giving me 4 degree beamwidth.
My drop in CN being longer (starting earlier and ending later) than the prediction.

I had a tweak of my dish yesterday after co-lin just to check the dish was - as far as possible - 'aligned.'
It appeared so.

It seems at times that tweaking can be counter productive?

Regards,
John
==============================

Yes, John, I find it useful to compare the solar outage to the prediction as an estimate of the errors in azimuth and elevation I likely have. I wrote my Solar Outage SNR program to automatically plot the data for later analysis.

https://www.satsignal.eu/software/beta.htm

Attached is one I made earlier....

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

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

David,

Yes of course, and I have always used this WXtrack function.

But, even with a 1 m dish I find that the co-lin begins before the 'begin' in the list noted and lasts
longer than the end prediction.
Especially if I recall correctly, around the max Closest.

I subtract 4 then 4 minutes from the predicted Peak - and likewise add 4 minutes plus 4 minutes to
the Peak - giving me 4 degree beamwidth.
My drop in CN being longer (starting earlier and ending later) than the prediction.

I had a tweak of my dish yesterday after co-lin just to check the dish was - as far as possible - 'aligned.'
It appeared so.

It seems at times that tweaking can be counter productive?

Regards,
John
=============================================

John,

If the outage is lasting longer than the prediction then perhaps the figures you are entering into the calculation are not appropriate? Dish size - for example - where a dish bought as "1m" may have an active area somewhat less, particularly if the 1m is actually the maximum axis of the ellipse rather than the "average" dimension of the two axes. There's also an efficiency figure - your dish flatness and illumination by the LNB won't be 100%. Again, what you mean by "co-lin begins" - is it the precise angular separation, or a certain number of dB? The dB figure will depend on the exact shape of your dish's response, not to mention any diffraction from nearby trees!

Just some thoughts....

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

geojohnt@...
 

David,

Thanks for your thoughts.

Right, my dish is supposed to be a 1 m dish.
It's maximum dimensions are 107 cm tall and 96.5 cm wide.
The reflective surface slightly less of course.

Which means the beamwidth is wider in the horizontal plane - slightly than the vertical?

The LNB is adjusted for max 'best focus' - SN - which is right up one end on the LNB throat 
in the LNB holder.
The skew and dish alignment - 'best SN alignment.'

Today was my 'day before max outage.'
It looked from the Satellite-calculation map that today was/or around, your max outage day.

Iv'e had some thoughts, is WXtrack and satellite-calculations predicting for a prime focus dish 
or an offset dish?
And, are they both predicting for total degradation in SN or just the 3 dB level?

Satellite-calculation displays -1 dB to  -6 dB contours in the outage cone.
I watched the progress of the contours across my location and they pretty well matched my SN variation.
And, I think I'm right in saying that their 'outage time predictions' which were about the same as WXtrack 
were for the 3 dB level degradation looking at the passing cone levels.

My 'drop from and rise to original signal level' (13.2 dB to 13.2 dB) was around 18 minutes.
And about 17 yesterday. 
My peak outage SN was 7.0 dB.

Ah, just noticed on WXtrack - Solar Outage, First nulls beamwidth 3.73 degrees. ???
My drop in SN starts around the time the sun is 2 degrees from 10A and ends around the sun being 2 degrees past.

WXtrack and satellite-calculation almost agree on prediction times (today -0.28 degrees Closest):
Begin 11:21 Peak 11:28:11 End 11:34 - a period of 13 minutes.
My total outage period was 18 minutes.


I tried reducing the dish size a bit in WXtrack which changed the beamwidth but didn't alter the Begin 
Peak, End, times much.

So, the question seems to be, are the predictions based on the 3 dB outage level and not the total outage?

Regards,
John.

++++++++++++++++++ 

 
 John,

If the outage is lasting longer than the prediction then perhaps the figures
you are entering into the calculation are not appropriate?  Dish size - for
example - where a dish bought as "1m" may have an active area somewhat less,
particularly if the 1m is actually the maximum axis of the ellipse rather
than the "average" dimension of the two axes.  There's also an efficiency
figure - your dish flatness and illumination by the LNB won't be 100%.
Again, what you mean by "co-lin begins" - is it the precise angular
separation, or a certain number of dB?  The dB figure will depend on the
exact shape of your dish's response, not to mention any diffraction from
nearby trees!

Just some thoughts....

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

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

-----Original Message-----
From: David J Taylor via Groups.Io <david-taylor@...>
To: MSG-1 <MSG-1@groups.io>
Sent: Fri, 28 Feb 2020 7:39
Subject: Re: [MSG-1] Realtime co-lin outage map for your location.

David,

Yes of course, and I have always used this WXtrack function.

But, even with a 1 m dish I find that the co-lin begins before the 'begin' 
in the list noted and lasts
longer than the end prediction.
Especially if I recall correctly, around the max Closest.

I subtract 4 then 4 minutes from the predicted Peak - and likewise add 4 
minutes plus 4 minutes to
the Peak - giving me 4 degree beamwidth.
My drop in CN being longer (starting earlier and ending later) than the 
prediction.

I had a tweak of my dish yesterday after co-lin just to check the dish was - 
as far as possible - 'aligned.'
It appeared so.

It seems at times that tweaking can be counter productive?

Regards,
John
=============================================

David J Taylor GM8ARV 🏴󠁧󠁢󠁳󠁣󠁴󠁿 🇪🇺
 

David,

Thanks for your thoughts.

Right, my dish is supposed to be a 1 m dish.
It's maximum dimensions are 107 cm tall and 96.5 cm wide.
The reflective surface slightly less of course.

Which means the beamwidth is wider in the horizontal plane - slightly than the vertical?

The LNB is adjusted for max 'best focus' - SN - which is right up one end on the LNB throat
in the LNB holder.
The skew and dish alignment - 'best SN alignment.'

Today was my 'day before max outage.'
It looked from the Satellite-calculation map that today was/or around, your max outage day.

Iv'e had some thoughts, is WXtrack and satellite-calculations predicting for a prime focus dish
or an offset dish?
And, are they both predicting for total degradation in SN or just the 3 dB level?

Satellite-calculation displays -1 dB to -6 dB contours in the outage cone.
I watched the progress of the contours across my location and they pretty well matched my SN variation.
And, I think I'm right in saying that their 'outage time predictions' which were about the same as WXtrack
were for the 3 dB level degradation looking at the passing cone levels.

My 'drop from and rise to original signal level' (13.2 dB to 13.2 dB) was around 18 minutes.
And about 17 yesterday.
My peak outage SN was 7.0 dB.

Ah, just noticed on WXtrack - Solar Outage, First nulls beamwidth 3.73 degrees. ???
My drop in SN starts around the time the sun is 2 degrees from 10A and ends around the sun being 2 degrees past.

WXtrack and satellite-calculation almost agree on prediction times (today -0.28 degrees Closest):
Begin 11:21 Peak 11:28:11 End 11:34 - a period of 13 minutes.
My total outage period was 18 minutes.


I tried reducing the dish size a bit in WXtrack which changed the beamwidth but didn't alter the Begin
Peak, End, times much.

So, the question seems to be, are the predictions based on the 3 dB outage level and not the total outage?

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

John,

Physically it seems that the dish will give a narrower beam in azimuth than elevation, but I haven't checked that.

The predictions are given as angular separation, for a nominal -3 dB down from the dish pointing axis. No consideration of actual signal level. You will find some degradation before and after those times as the dish etc. isn't perfect, and the sun isn't a point source.

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

geojohnt@...
 

David, 

Thanks again.

Ah, I hadn't thought about the sun not being a point source - actually it is rather large compared 
to the 'pin point' satellite it passes - and takes time from limb to limb to pass the satellite 
from our point of view.
I'm sure someone on the group will be able to say how long it takes for the sun, limb to limb, to 
pass the satellite.

And as you say, dish surface accuracy is another factor.

And I still (possibly) have the 'fir tree effect?'
Though the shadow of the western edge and bulk of fir tree - which is higher than the elevation of 
10A - is just, completely clear of my dish, 2 degrees before solar crossing of the dish. 

Today was my closest separation day - the sun was directly behind 10A, it appears, in a 
line running through the English Channel, according to the satellite-calculation map.
Yesterday it was through southern Scotland.

Oh, BTW, after my outage today my SNR went up 0.3 dB - from the usual and earlier level from 
around 11:38 to around 12:00.
This was also 'seen' by several stations on your EUMETCast reporting page graphs:
Huizen, Lodz, Naila, Wienerwald.

????

Regards,
John.


===============================

John,

Physically it seems that the dish will give a narrower beam in azimuth than 
elevation, but I haven't checked that.

The predictions are given as angular separation, for a nominal -3 dB down 
from the dish pointing axis.  No consideration of actual signal level.  You 
will find some degradation before and after those times as the dish etc. 
isn't perfect, and the sun isn't a point source.


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

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