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Service Providers >> TooWay and KA-SAT satellite >> Measuring link quality
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Message started by frankie on Jan 14th, 2014 at 5:58pm

Title: Measuring link quality
Post by frankie on Jan 14th, 2014 at 5:58pm
How to measure and report link quality?  Recent quote from another thread,

"Your C/N should be good, comparable with other sites in same relative position in the beam.  I've heard of values of receive C/N=13 dB at beam centre and 10 dB at beam edge.  (More measurements please !)"

So, the purpose of this thread is to clarify ideas of what to measure, and how to report the results so we can easily collate measurements from as many people as possible.

As an example, I've cobbled together a cron job which runs every 15 minutes and gives measurements for:

(1) time to ping example.net (I chose example.net because it is reserved by IANA for this kind of purpose)
(2) some weather details for my location from wunderground.com (it's easy to get these by registering for free with wunderground.com and they give you an api key)
(3) Forward and Return SNR as reported by checkportal.skylogicnet.com

I set this to run every 15 minutes because that is how often checkportal.skylogicnet.com updates its measurements.  Here are a couple of hours worth of results.  As you can see, we're having great weather here today.  20 kms from Northern edge of beam 19 (green, central Italy):


Quote:
15:35:02 ping example.net 1737ms
9 Celsius RH 94% 1012 mb ppt/h 0 mm wind WNW 3 km/h vis 0 km Rain
Forward SNR 11.8 dB  (last update: 14/01/2014 15:32:35 UTC) 
Return SNR 10.95 dB  (last update: 14/01/2014 15:32:35 UTC) 

15:50:02 ping example.net 1611ms
8 Celsius RH 96% 1012 mb ppt/h 0 mm wind WNW 3 km/h vis 0 km Rain
Forward SNR 11.8 dB  (last update: 14/01/2014 15:47:35 UTC) 
Return SNR 11.1 dB  (last update: 14/01/2014 15:47:35 UTC) 

16:05:02 ping example.net 874ms
8 Celsius RH 97% 1012 mb ppt/h 0 mm wind WNW 3 km/h vis 0 km Rain
Forward SNR 11.6 dB  (last update: 14/01/2014 16:02:41 UTC) 
Return SNR 10.86 dB  (last update: 14/01/2014 16:02:41 UTC) 

16:20:02 ping example.net 860ms
8 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Rain
Forward SNR 11.6 dB  (last update: 14/01/2014 16:17:39 UTC) 
Return SNR 10.41 dB  (last update: 14/01/2014 16:17:39 UTC) 

16:35:02 ping example.net 857ms
8 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Rain
Forward SNR 11.8 dB  (last update: 14/01/2014 16:32:40 UTC) 
Return SNR 10.28 dB  (last update: 14/01/2014 16:32:40 UTC) 

16:50:02 ping example.net 2014ms
8 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Rain
Forward SNR 11.7 dB  (last update: 14/01/2014 16:47:39 UTC) 
Return SNR 10.51 dB  (last update: 14/01/2014 16:47:39 UTC) 

17:05:03 ping example.net 854ms
8 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Rain
Forward SNR 11.9 dB  (last update: 14/01/2014 17:02:38 UTC) 
Return SNR 10.44 dB  (last update: 14/01/2014 17:02:38 UTC) 

17:20:03 ping example.net 809ms
7 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Rain
Forward SNR 11.1 dB  (last update: 14/01/2014 17:17:40 UTC) 
Return SNR 10.09 dB  (last update: 14/01/2014 17:17:40 UTC) 

17:35:03 ping example.net 1992ms
7 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Patches of Fog
Forward SNR 11.1 dB  (last update: 14/01/2014 17:32:39 UTC) 
Return SNR 11.27 dB  (last update: 14/01/2014 17:32:39 UTC) 

17:50:03 ping example.net 837ms
7 Celsius RH 98% 1001 mb ppt/h 0 mm wind WNW 3 km/h vis 10 km Patches of Fog
Forward SNR 11.3 dB  (last update: 14/01/2014 17:47:43 UTC) 
Return SNR 10.77 dB  (last update: 14/01/2014 17:47:43 UTC)

This is just an experiment.  Any suggestions for improving it welcome.  If many people could report measurements so we can collate them, that would be most useful I think.

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