Service Outage on AlphaSat (back up). APAC is still down


#101

Hi guys! I can not receive a signal with alpasat I’m in Moscow. can you tell something


#102

Could you please provide screen dumps of the Satellite and Status tabs from the Tuner window in Skylark?


#103

unfortunately I do not use skylark. I’m using outernet on linux.
I can only make a screenshot of gqrx or outernet demodulator


#104

Hi Jackv,
sorry can’t help much with your issue, only to remind you that Alphasat recently had a frequency change, are you aware of that? New image - with new EMEA frequency

My question to you, if I may, what Linux setup are you using with Outernet? Ubuntu, Mint? on PC/MAC/laptop?
GQRX for other than Outernet? Outernet demodulator, which one? Outernet decoder?
My aim is to re-deploy my Outernet hardware, software and current little expertise after the Team as swithced off the APAC beam.
Any help from you and others much appreciated
spossiba
Luigi


#105

I’m not familiar wih this setup

Please provide both screenshots and maybe we can spot some obvious errors.

Have you received Outernet with this setup before?


#106


#107

I recently found out about the outernet because there is no information in Russian.
I want to first try to take a signal on sdr-rtl before buying a dreamcacher.
hardware:
macbook pro
sdr-rtl.com v3
lna based in spf5043z 50-4000mhz 22db gain
handmade pach antenna and helical antenna


#108

Yes, I know about the frequency change alphasat, but the signal on the new frequencies also does not. I’m using the virtual box with the ubuntu guest system. at the moment I’m doing the code under python and docker so it’s more convenient (imho)


#109

I’m 99% sure that you LNA is down… -132 dBm RSSI is only RTL-SDR internal noise, no signal from LNA. You might forgotten turning on the bias tee in your RTL-SDR:


“Feature 2: Software Selectable Bias Tee”


#110

lna is 100% working and has an external biast feed not used.
I tested on another lna with an increase of 18db the same result.
Perhaps there is no coverage area in eastern Europe or the city creates background noise drowning satellite signal


#111

No! You should have signal there… If your LNA works absolutely sure then you have a disconnected (open circuit) RF path somewhere. Again, as mentioned the -132 dBm RSSI means absolutely no RF energy gets into your RTL-SDR (not even the self noise of LNA without antenna).

You might not using your RTL-SDR in quadrature mode so listening the wrong ADC channel… or you have HW problems as descirbed above, those are my last guesses.

For debugging you can verify your setup against this signal, you should see this in spectrum plot:


#112

From memory If you use virtualbox you might have trouble with the USB versus usb2 conflict in Virtualbox.

I had to fiddle a lot to get Virtualbox guest edition etc to do USB2 to talk to my RTL dongle.

If you want a vitrtualbox gqrx already set up try Andy Ham radio disk. I think he is up to number 18.


#113

Hello! I’ve still checked and I’m not sure that the RSSI is the raw rf signal level


I can not change mode sdr -rtl for quadrature demodulation.
all actions for signal reception and demodulation make sdr100 binary.
what comes inside the sdr100 secret because there is no source code.
sdr100 does not have any documentation and the sdr100 -help command does not give all the values ​​accepted by the program. example:
[email protected]:~# export LD_LIBRARY_PATH="/usr/local/sdr.d/starsdr-rtlsdr"
[email protected]:~# sdr100 -h
sdr100 V1.0.4, Outernet SDR satellite demodulator.

Compiled for ARM processors with hardware floating point.
Usage: [-f Tune frequency (MHz) (default: 1539.87250 MHz)]
[-u Frequency uncertainty +/- (Hz) (default: +/-4000 Hz)]
[-r Symbol rate (sym/sec) (default: 4200 Hz)]
[-a Antenna pointing mode. Use aPkmn in the console display for aiming.]
[-d Device index (default: 0)]
[-c Disable console input/output (default: enabled)]
[-h this help]

In the script with the presets, additional parameters are assigned which can only be guessed. example:
cat /usr/local/share/outernet/presets
COMMON="-u 4000 -r 4200 -s 1 -b 0.2 -w"
AMERICAS="-f 1539.8725 $COMMON"
EURAF="-f 1546.25 $COMMON"
APAC="-f 1547.3459 $COMMON"

I’ll attach 2 more screenshots from gqrx with lna turned on and off
as seen in the screenshot with the included lna a very weak signal at at 1546.25mhz is there but it does not match the declared width of 4khz

LNA UP:

LNA DOWN:

PS and forgive me for my English

and I do not rule out the possibility that the signal on the territory of the Russian Federation can be silenced.


#114

Could it be that you are using a wide band RF amp and the signal is lost in all the noise?


#115

you can tell what that narrowly directed lna, max12000 in my country can not find


#116

try to get this, it has a SAW filter inside:
http://www.nooelec.com/store/lna-saw-filter-module-for-outernet-other-inmarsat-applications.html

Any narroband GPS LNA would do the job too. BTW I don’t see real signals on your spectrum plot but strong noise etc. only… Does your antenna oriented well? Is it on the roof etc?


#117

There are no visible obstacles especially when viewed through satellite AR


#118

hello, I listened to your advice and ordered lna nooelec. while I’m waiting for the delivery, I rebuilt the helical antenna with an approximate gain of 16dbi and connected it to homemade lna based on upc8211 and that’s what happened
The demodulator still does not see the signal and shows rssi -130


#119

hmmm… interesting this still looks like some internal noise of your SDR it’s not a sat signal…
if you have access to a VNA try to analyze your antenna. Also check your coax cables against open circuit faliure.