Re: Originally Re: [MSG-1] SR1 Traffic dial. - now missed packets
David J Taylor
Thanks for that, interesting.
So, the SR1 figures relate to received signal 'quality' and the TC figures rather to computer data handling activity and workload?
I reset SR1 and both TC's 'packet figures' yesterday at 12:10 GMT knowing bad weather was on the way.
The rain down here started around 18:00 GMT and wasn't that heavy but continuous.
I checked the 'packet readouts' at 22:41 GMT and all were still 0.
When I got up at 07:30 GMT we had had some heavy rain overnight and my HVS-1 TC icon was red with SR1's SNR around 11.00 dB
This went up to 12.0 + whilst sitting at the computer but the red HVS-1 icon didn't reset - which it does automatically when the LM is restored.
I opened HVS-1 HTML and saw that data was actually running - being shown on the graph.
And there was one Status error message from earlier.
Clicking reset, reset that and cleared the red TC icon.
So with data flowing despite the red task bar icon, the icon is slow to reset when the link margin rises above the threshold - it seems.
Or, I seem to recall, it remains red when a Status error message has been recorded.
This is a bit confusing(?), since a red TC task bar icon suggests lost lock and no data flowing?
It really needs another colour to inform of an error message warning?
Yellow for connecting, orange for message waiting, red for lost lock - no data throughput?
At 09:10 GMT I checked missed packets and HVS-1 showed Missed Packets 1611 - Recovered Packets 0.
BS showed Missed Packets 2114 - Recovered Packets 45
SR1 showed Bad Frame Count 2226 - Bad Packet Counts 16942.
I then reset all at that time.
I think you are saying that if the computer is struggling with the amount of data/services it is having to deal with, TC will show lost/missed packets of data?
Does then low/er SNR - though above link margin threshold, also add to this loss?
I'm running a single PC system 24/7:
Intel i5-4690K CPU @ 3.50 GHz.
16 GB RA1.81 T HDD
Windows 10 Home
and no RAMDisk.
Programmes running: MSG-4 - + FSD, IODC, RSS, Animator, AVHRR Manager (NOAA-19, Metop A B C) Metop Manager B, Metop Manager C, GOES-16, GOES-17, HImarawi, and receive (store) Modis data - programme not running.
Task Manager appears to show my computer is not stressed - but of course I only look at that occasionally.
However, dare I say, your 'favourite' Anti Virus Software programme BullGuard ???? does kick in every now and again to do 'house cleaning,' optimisation and defraging - and goodness knows what else with the HDD working on this as well.
The red icon behaves differently in two circumstances:
- with signal loss and restoration the icon goes red and then clears.
- with some file errors the icon stays red, until you reset it. The error message gives a clue to the problem.
I think the present behaviour is satisfactory, once you know the above.
The missed/recovered packet count can be greater if the link margin is lower, yes, particularly if there are variations in the signal causing momentary drop-outs (wind is a cause in this location). The lower the link margin, the greater the chance of it being below the threshold.
Even with the perfect signal (well, 4 dB or greater steady link margin), if any PC activity causes the data stream to be interrupted, that can result in lost packets. Yes, virus scanners can cause this, so if the PC doesn't have any users, turn off the scanner, of if there's a keyboard someone can interact with stop the scanner looking at the EUMETCast directories. In the past, a RAMdisk has been shown to ameliorate this problem, but I'm not so sure these days with faster PCs and updates to TelliCast.
As I've mentioned many times before, automatic monitoring with e.g. MRTG can help you tie periods of loss to periods of high CPU, low memory, high network I/O, or scheduled malware scanning. Otherwise it's more guesswork.
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