Re: Realtime co-lin outage map for your location.


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@blueyonder.co.uk
Twitter: @gm8arv

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