Topics

inmarsat C l-band satellites #aero

Roland Fechter
 

Hallo,
Could you please tell me the current and future position -  azimuth & Elevation - of these satellites
here in central Europe. I have been unable to receive any data despite spending much time on my southward facing balcony open also towards the East.
I used a gps patch antenna modified allegedly for the l-band together with my allegedly fine nooelec sawbird lna
with the 1200baud freq on my funcube pro plus dongle. Despite going from a 20m long cable to a 5m long one
not a trace of data were received by me nor the sdrsharp I also used.
Either both the gps antenna plus the sawbird are rubbish or I miss the correct position of these sats altogether.
I still maintain some hope of enjoying Aero within my lifetime thanks to further hints of you experts !
I look forward to these.
Thanks in advance.
Regards,
Roland

Willi Rauschenberg
 

Roland,
press the satellite button within MultiPSK and You will see the required data, given  You have input and saved Your long/lat-information of Your QTH within the personal settings.

Viele Gruesse
Willi Rauschenberg


Am 08.12.2018 um 22:00 schrieb Roland Fechter <fly-fechter@...>:

Hallo,
Could you please tell me the current and future position -  azimuth & Elevation - of these satellites
here in central Europe. I have been unable to receive any data despite spending much time on my southward facing balcony open also towards the East.
I used a gps patch antenna modified allegedly for the l-band together with my allegedly fine nooelec sawbird lna
with the 1200baud freq on my funcube pro plus dongle. Despite going from a 20m long cable to a 5m long one
not a trace of data were received by me nor the sdrsharp I also used.
Either both the gps antenna plus the sawbird are rubbish or I miss the correct position of these sats altogether.
I still maintain some hope of enjoying Aero within my lifetime thanks to further hints of you experts !
I look forward to these.
Thanks in advance.
Regards,
Roland

Chris van Lint
 

Hello Roland,

Of course you will be decoding AERO data soon.  All that is needed is a bit of patience.

If you want to "see" where a particular satellite is, I would recommend that you download David Taylor's excellent satellite tracking programme "Wxttrack". https://www.satsignal.eu/software/wxtrack.htm This software is freeware and it allows you to look at the position of any satellite in both real time, as well as any specific time /day you nominate.  Indeed it would be a good idea to use this software to determine a time period during which the satellite moves the least in terms of azimuth and elevation, as this makes pointing easier.

The specifications of the Nooelec Sawbird LNA show that it is ideal for Inmarsat L-Band reception.  How are you feeding power to the LNA (through the coax or direct at the LNA)?  If you feed through the coax, what type of bias-tee are you using on the funcube side?  Is it the correct voltage for the Nooelec LNA.

Are you using the correct polarization.  Using the correct polarization is crucial and if the rotation angle is wrong you may not see a signal. In my case I am using LHCP to decode 4F1 and I use a RHCP patch looking into a 120cm prime focus dish.  (following the principles of optics the signal will be reversed). There is no need to use a dish, it is just that I had one lying around. I have no idea what the aerial polarization of your particular satellite is.  Maybe a member in Europe will be able to tell you.

There are NO AERO ACARS burst transmissions on the L-Band (these are used on the C-Band).
So you are looking at continuous signals around 1.5kHz wide for 600bps, 3.0kHz for 1200 bps and 15kHz for 10500bps.  Make sure you use the correct bps value on the Multipsk side.  The majority of signals are 600bps and 10500bps there are a few 1200bps channels.  (There are also some intermittent 8600bps channels which transmit ground to aircraft voice communications). All channels will transmit data (SUs) when correctly tuned and decoded.  However only some of them will contain ACARS data at any given time.

I have some other ideas to help you get started, but it would perhaps be better to deal with them off-list.

mfg Chris aus Australien.

.At 07:00 AM 9/12/2018, you wrote:

Hallo,
Could you please tell me the current and future position -  azimuth & Elevation - of these satellites
here in central Europe. I have been unable to receive any data despite spending much time on my southward facing balcony open also towards the East.
I used a gps patch antenna modified allegedly for the l-band together with my allegedly fine nooelec sawbird lna
with the 1200baud freq on my funcube pro plus dongle. Despite going from a 20m long cable to a 5m long one
not a trace of data were received by me nor the sdrsharp I also used.
Either both the gps antenna plus the sawbird are rubbish or I miss the correct position of these sats altogether.
I still maintain some hope of enjoying Aero within my lifetime thanks to further hints of you experts !
I look forward to these.
Thanks in advance.
Regards,
Roland

Paul Gulliver
 

Hi Roland,

If I remember correctly you are in Germany, the best satellite for you would be Alphasat (located at 25 deg East) which gives an approx azimuth of 160 degrees and an elevation of 30 degrees - patch antennas are not too directional.

When I first started on L band I used this patch antenna https://imgur.com/a/hMD86 with these dimensions:
Reflector Size: 170 mm x 170 mm
Patch Size: 98 mm x 98 mm
Corner Trim: 21 mm from top right and bottom left corners
Coax Connection (Probe): 25 mm from bottom edge
Height of patch from reflector: 7 mm

Material I used was copper sheet

It worked reasonably well without any in line amplifier - even from within the house although the signal was stronger outside

Regards

Paul


On 08/12/2018 at 21:00, Roland Fechter <fly-fechter@...> wrote:
Hallo,
Could you please tell me the current and future position -  azimuth & Elevation - of these satellites
here in central Europe. I have been unable to receive any data despite spending much time on my southward facing balcony open also towards the East.
I used a gps patch antenna modified allegedly for the l-band together with my allegedly fine nooelec sawbird lna
with the 1200baud freq on my funcube pro plus dongle. Despite going from a 20m long cable to a 5m long one
not a trace of data were received by me nor the sdrsharp I also used.
Either both the gps antenna plus the sawbird are rubbish or I miss the correct position of these sats altogether.
I still maintain some hope of enjoying Aero within my lifetime thanks to further hints of you experts !
I look forward to these.
Thanks in advance.
Regards,
Roland

Paul Gulliver
 

Roland,

Looking back through your previous posts you mention the A154 patch antenna - is this the item you're using, if so, this also requires a DC power feed (that's how I read the spec on the web site). Just confirm you have two bias tees, one for each device (LNA and Patch) - I don't believe the Nooelec LNA passes the dc through to the input of the device.

Paul