When my window was open, i got a SNR of 4-4,5 db in comparision to the 2,5-3,5 db SNR with it closed.
That is understandable because the Signal has to travel trough glas and the argon gas between it (double glazing).
But the starnge thing is, that when is stand directly behind the receiver, i get a SNR of 6-6,5 db. What is the reason for that? I was not touching it, so it should not use me as a kind of antenna or so.
I have mine shielded. you need to be careful not to create “stray capacitance” between the surface mount components that could cause weirdness, so the shield should be as far away from the board as possible. I found some benefit.
I simply wrapped the LNA in bubble wrap & put aluminium foil around that (grounded at the SMA connector)
I have found at least ONE culprit for loss of signal
There is a “steerable” ku band dish about 20 feet from, and parallel to, my patch antenna… when it is “listening” to certain satellites it seems to desensitise the receiver … cables are not running together or anything like tha, my best guess is that the LNA on the dish is radiating spuriously somewhere!
I am going to search & find it if I can.
Good thing is that when it is pointing at the “local” (28.5E) bird I have no problems…
The IF of the Ku band LNB covers the same frequency range as the receiver.
It could be that there is a strong IF component on the same frequency as Outernet when receiving
certain satellites. However, this should not be radiated. Check the cabling and attachment of the
connectors. With bad cable you can have similar issues when using a DECT cordless phone nearby,
it transmits in this band as well and it can interfere with certain transponders.
Grafica de la señal en Alphasat 25E, desde el día del fallo de la señal hasta hoy, el intervalo de captura de los datos es de 10 minutos, también indico el cambio de soleado a nublado (con algo de lluvia), la instalación no se ha tocado ni cambiado nada, el único cambio es el del clima.
Salu2 y suerte.
Translation:
Whatever may interest you.
Graph of the signal in Alphasat 25E, from the day of the signal failure to today, the data capture interval is 10 minutes, also indicated the change from sunny to cloudy (with some rain), the installation is not Has touched or changed anything, the only change is the weather.
Yo le he eliminado el “+125” al script, y he creado un eje secundario con los datos del RSSI, así evitamos hacer cuentas, y un problema que yo he tenido al importar el txt, en las opciones avanzadas hay que decirle que el separador decimal es el punto ”.”, quizás a otros no le haga falta hacer esto, pero por si acaso lo digo, que a mí me ha tenido liado días…
Translation:
What has cost me! I have had to learn from scratch Excel and graphs.
I have deleted the “+125” to the script, and I created a secondary axis with the RSSI data, so we avoided to do accounts, and a problem that I had when importing the txt, in the advanced options we have to say that the Decimal separator is the point “.”, Maybe others do not need to do this, but just in case I say it, I have had me bundled days …
**pi@raspberrypi:~ $ ./snr_log_SL_1v0.sh 192.168.1.5 | tee snr_20170129.txt**
Sun 29 Jan 22:47:42 UTC 2017 : 2.45
Sun 29 Jan 22:47:57 UTC 2017 : 2.91
Sun 29 Jan 22:48:12 UTC 2017 : 2.27
Sun 29 Jan 22:48:27 UTC 2017 : 2.86
This example above logs the 192.168.1.5 Skylark device SNR into a text file (in every 15 sec, you can change that from script). This can be run on Linux computer, I’m using my RPi 2 mostly with Raspbian Jessie.
Also here is a small google sheet for chart visualization, the trick here using moving average of 10 to smooth the glitches.
thank you for the short script, but is there any documentatin about the api (/en/state doesen’t work) in librarian? The Script you posted is for Skylark as you say. Do you have an older Version for librarian as well?
Even a url that gives me the Information would be enough.
@Abhishek /en/state gives me a 404 not found error.
Just as a status from my receiver, its around 3db SNR at the moment. (VPN FTW )
Have you plugged in the correct IP of the receiver?
Its a known working script - and kinda self explanatory. Zoltan has been using it for months.
Note that Librarian really didn’t have an external “api” system. This is just a hack using the internal URL it used to fetch tuner status.
#!/bin/bash
ip=$1
if type curl 2>&1 | grep -q "not found"
then
echo curl is not installed. Please install first with "sudo apt install curl"
echo 0
fi
while true
do
a=$(curl -s http://$ip/en/state/ | sed 's/.*, "snr": \([^,]*\),.*/\1/g')
if [ "{}" != "$a" ]
then
echo -n $(date) ": "
echo $a
fi
sleep 1
done
Just call it with the IP of the receiver as the first (and only) param.
When you look at my stats from yesterday, there is a repeating pattern like a wave.
That could be a rotation of the satellite would be my guess. I wonder if the statistics of today will show the same pattern, that would strenghten my presumption of a unwanted Rotation.
The weather here is still very cloudy, just like yesterday, so the Signallevel should be similar.
I’am very interested in the Response from Inmarsat
Whilst I don’t have logging running ( I have not had time whilst i am near the CHIP to fiddle) I can confirm that my SNR is up around 7 - 8 now (as opposed to 5-6) at 51Deg N , with nothing changed or touched at all .
I actually wonder if there has been something in a lower orbit (not geostationary, but possibly elliptical) “eclipsing” the Bird, moving slowly, The drop came suddenly, but it has come back a lot more gradually…
Just my two cents worth
.Ahora la señal es alta, con picos de 8, como antes del fallo, cielo bastante despejado, he creado una tarea para capturar cada 1 minuto, para ver mejor la evolución de la señal.
Translation:
Now the signal is high, with peaks of 8, like before the fault, clear sky, I have created a task to capture every 1 minute, to better see the evolution of the signal.
)
