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MultiPSK and C-Band AERO #HelpNeeded

DSP Engr
 
Edited

I am able to pick up C-Band AERO 10500 baud burst signals using an SDRplay RSP, but MultiPSK only shows that it can operate with 1200 baud burst signals. I am not seeing 1200 baud AERO burst signals on C-Band, but am seeing many 10500 burst signals. Are there any plans to update MultiPSK to receive and decode the C-Band AERO 10500 baud burst signals?
Information on decoding C-Band AERO 10500 burst signals is here: http://jontio.zapto.org/hda1/c-band.html

The image below shows C-Band AERO 10500 burst signals. Using a Titanium C1W-PLL LNBF and SDRplay RSP2 for reception.

Patrick Lindecker
 

Hello,

 

Congratulations to have been able to receive these signals (it is not easy). I tried about one year ago with a 1 m dish, a C1W-PLL and a RTL/SDR V3, but I could not even see the presence of 10500 bauds signals (only 1200 bauds signals). So I abandoned this decoding. I suspect that the force of reception depends on the location. Perhaps with a 2 m dish, I would have seen these signals (?). Or perhaps the RTL/SDR V3 is not sufficient (a SDRplay would maybe be preferable).

 

73

Patrick

 

De : multipsk@groups.io [mailto:multipsk@groups.io] De la part de DSP Engr
Envoyé : dimanche 26 avril 2020 20:57
À : multipsk@groups.io
Objet : [multipsk] MultiPSK and C-Band AERO #HelpNeeded

 

I am able to pick up C-Band AERO 10500 baud burst signals using an SDRplay RSP, but MultiPSK only shows that it can operate with 1200 baud burst signals. I am not seeing 1200 baud AERO burst signals on C-Band, but am seeing many 10500 burst signals. Are there any plans to update MultiPSK to receive the C-Band AERO 10500 baud burst signals?
Information on decoding C-Band AERO 10500 burst signals is here: http://jontio.zapto.org/hda1/c-band.html

The image below shows C-Band AERO 10500 burst signals. Using a Titanium C1W-PLL LNBF and SDRplay RSP2 for reception.
 




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DSP Engr
 
Edited

Picking up AERO 10500 burst signals on C-Band Inmarsat 4F3 from mid-Southern-U.S. with a 30 inch dish, RSP2, and a Titanium C1W-PLL LNBF.


Picking up C-Band AERO 10500 Burst signals, receiving with the RSP2, Titanium C1W-PLL LNBF, and SDRuno, decoding with JAERO, and plotting using Virtual Radar Server came together quickly without issues. Would liked to have been able to use MultiPSK so was wondering if there were plans to add 10500 burst decoding for C-band reception in MultiPSK?



DSP Engr
 
Edited

"Kevin Elliott

Hey there!
 
Which dish kit is that? What LNB and LNB mount are you using? I’d like to pick one of these up.
 
Best,
Kevin"


Hi Kevin,

The dish was purchased from here: https://www.ebay.com/itm/Winegard-30-Inch-Diameter-Universal-Satellite-Dish-Antenna-DS-2076/302127102748?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 

This dish works OK with the C1W-PLL LNBF for C-Band AERO from Southern mid-U.S. states on 4F3, but you will likely need a larger dish, if in the Northern U.S., Canada or Europe. Will need to see how well it works on 3F5 when I get a chance. I use a 4ft helical antenna to pick up L-band AERO on 4F3 and 3F5 here and the levels are pretty close to the same from each satellite so I am expecting to pick up C-band 3F5 without issue. To position on 4F3, I was using the Ku-band PLL LNB (left dangling) in the picture to line up with Galaxy 19, then just laying it aside, moving the dish 0.6 degrees clockwise to position to Inmarsat 4F3 and then installing the Titanium C1W-PLL LNBF. This was a temporary setup so I just used plastic wire ties to affix the C1W-PLL LNBF to the existing Ku band fixture. Not an optimum setup for sure as it sets the C1W-PLL LNBF about an inch higher than it should be so better reception should result with it installed better. As for a permanent mount, I was thinking of cutting the plastic Ku-band mount that came with the antenna and then cutting the plastic mount for the C1W-PLL LNBF so they will mate properly and then using 3M Scotch-Weld DP460 industrial adhesive to glue them together.

Kevin Elliott
 

Oh I see, so I’m in Northern California, and I have used L-band on 4F3 with my modified GPS antennas from RTL-SDR etc… I have a pair of Ku-band dishes and was hoping to use a C-band LNBF to do what you are doing for C-band AERO.

Sounds like you had to do some customization for the mount?

Do you think it’ll work with a Ku-band dish? I don’t have the space for a traditional C-band dish.

Kevin

On Apr 27, 2020, at 10:43 AM, DSP Engr <dsp.engr.pe@...> wrote:

"Kevin Elliott

Hey there!
 
Which dish kit is that? What LNB and LNB mount are you using? I’d like to pick one of these up.
 
Best,
Kevin"


Hi Kevin,

The dish was purchased from here: https://www.ebay.com/itm/Winegard-30-Inch-Diameter-Universal-Satellite-Dish-Antenna-DS-2076/302127102748?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 

This dish works OK with the C1W-PLL LNBF for C-Band AERO from Southern mid-U.S. states on 4F3, but you will likely need a larger dish, if in the Northern U.S., Canada or Europe. Will need to see how well it works on 3F5 when I get a chance. I use a 4ft helical antenna to pick up L-band AERO on 4F3 and 3F5 here and the levels are pretty close to the same from each satellite so I am expecting to pick up C-band 3F5 without issue. To position on 4F3, I was using the Ku-band PLL LNB (left dangling) in the picture to line up with Galaxy 19, then just laying it aside, moving the dish 0.6 degrees clockwise to position to Inmarsat 4F3 and then installing the Titanium C1W-PLL LNBF. This was a temporary setup so I just used plastic wire ties to affix the C!W-PLL LNBF to the existing Ku band fixture. Not an optimum setup for sure as it sets the C1W-PLL LNBF about an inch higher than it should be so better reception should result with it installed better. As for a permanent mount, I was thinking of cutting the plastic Ku-band mount that came with the antenna and then cutting the plastic mount for the C1W-PLL LNBF so they will mate properly and then using 3M Scotch-Weld DP460 industrial adhesive to glue them together.

DSP Engr
 

Kevin,

The dish I am using was intended for Ku-band as it came with a Ku-band LNBF mount, but I am using it in the C-band. The geometry and positioning of the focal point of the parabola is not frequency dependent, so as long as you line up the C1W PLL LNB exactly where the focal point was for the intended Ku-band feed, it should be fitted correctly at that point. Note that when using the C1W-PLL LNBF, the manufacturer has a sheet for installing the depolarizing plate to enable it to be used for circular polarity https://www.titaniumsatellite.com/downloads/Guides/LNBF%20Install%20Guide.pdf . Follow that so it is working correctly for an RHCP polarized signal from the satellite being received and being reflected from the dish into the LNB (you set the LNB to operate with LHCP as the reflected RHCP signal becomes LHCP after reflecting off the dish into the LNB). For use with Inmarsat AERO C-band reception, the proper position of the dielectric slab depolarizing plate when looking in from the front of the LNB is at an angle mid-way between the angle of both antenna elements. Then power the LNB with 18V for power. Let me know if you need a better picture than the one in the manufacturer's sheet. Do not use the large scalar ring feed attachment that comes with it and do not use an offset feed attachment as these do not help at all with the small 30-inch offset dish. If you are using a large 6ft (2m) dish antenna, then the additional feed attachments will likely help. 

DSP Engr
 
Edited

Kevin,

Here is an image of the 4F3 10500 burst AERO signals and the approximate range of frequencies you will find them in when down converted from C-band with the C1W-PLL LNB:

If using an SDRplay RSP, set for 5Msps sampling, decimation of 8 and it will enable you to see the signals and set up to receive them easily. The frequencies shown below are listed in kHz, so are in the 1.535 GHz range.

Rich O.
 

Hello DSP Eng:

I have the same setup as shown pictures in your reply but I am getting no signals.  I am using a direct tv power injector.  As suggested, I removed the scaler ring, tried different positions, adjusted LNB ( rotated and moved further/closer to dish),  still no joy.

i know the receiver and software work as I can receive L -band signals just fine.  Perhaps I have a bad LNB.

Rich

Chris van Lint
 

I must have somehow missed previous messages on this topic, as I have no idea what questions and replies were asked/provided in the past.

I have little bit of experience with c-band aero acars reception and decoding, so if you provide some more detail, I might be able to help.

In the meantime you might like to have a look at the following links, which give step-by-step instructions on how to decode both 1200 bps and 1050 bps signals, albeit not with Multipsk, however the set-up principles are the same:

http://planeplotter.pbworks.com/w/file/fetch/118938423/Receiving%20and%20decoding%20C-band%20Inmarsat.pdf


http://planeplotter.pbworks.com/w/file/fetch/121429833/C-Band_LNB_Mod-word.pdf

https://www.coaa.co.uk/Receiving%20and%20decoding%20multiple%20C.pdf


Chris

On 15/06/2020 15:07, Rich O. wrote:
Hello DSP Eng:

I have the same setup as shown pictures in your reply but I am getting no signals. I am using a direct tv power injector. As suggested, I removed the scaler ring, tried different positions, adjusted LNB ( rotated and moved further/closer to dish), still no joy.

i know the receiver and software work as I can receive L -band signals just fine. Perhaps I have a bad LNB.

Rich

tomandy
 

Tank You Chris.

DSP Engr
 

Hi Rich,

Positioning is very critical with a small approximately 1m dish antenna. Make sure it is positioned properly. Positioning can be very accurately checked and the antenna can be lined up with objects in your yard in the path indicated by zooming in while using the Dish Pointer application online at https://www.dishpointer.com/ .  I am assuming you are on C-band using a Titanium C1W-PLL LNBF or equivalent with the output from the LNBF in the frequency range shown in the April 27, 2020 #3104 image below. Also, be sure you have the dielectric slab properly installed to enable it to be used for left hand circular polarity (LHCP) https://www.titaniumsatellite.com/downloads/Guides/LNBF%20Install%20Guide.pdf . The correct operation is to have the dielectric slab positioned half way between each linear antenna element as shown in the image in the PDF file at the link provided and then set the voltage feeding the C1W-PLL to 18V. You want it set for LHCP, since the RHCP signals from the satellite will be reflected off the parabolic dish as LHCP. If the polarization of the LNBF or the positioning of the antenna are not correct, you won't see the signal. If you are using a small dish (around 1m), then do not use the scalar ring with the Titanium C1W-PLL LNBF as shown in the setup from April 27, 2020 #3096 below.

Chris van Lint
 

Just as a matter of interest; what size dish are you using? Is it primary focus or off-set.  Also which satellite are you trying to receive, since there are considerable variations in RF output between the Inmarsat birds.  You mentioned that you are sure that the receiver is OK, because everything works on the L-band.  Have you been able to monitor any of the voice transmissions A/C to ground?

73 VK4CVL

 15/06/2020 18:19, tomandy wrote:

Tank You Chris.


  

tomandy
 

Hi Chris,

My location is the Netherlands and for Inmarsat it is complete new for me.  At this moment I am falling and getting up

Op 16-6-2020 om 05:35 schreef Chris van Lint:

Just as a matter of interest; what size dish are you using? Is it primary focus or off-set.  Also which satellite are you trying to receive, since there are considerable variations in RF output between the Inmarsat birds.  You mentioned that you are sure that the receiver is OK, because everything works on the L-band.  Have you been able to monitor any of the voice transmissions A/C to ground?

73 VK4CVL

 15/06/2020 18:19, tomandy wrote:
Tank You Chris.

  



    

Paul Gulliver
 

Tomandy,

Guessing from your location you looking at Alphasat which is a version 4 satellite and has a lower output power than the V3 (3F5) satellite at 54W
From my location in Southern UK I can get C band aero data from 3F5 using a 1.1m offset dish but unable to get anything from Alphasat.
From others that can receive this bird I understand they use a 1.4m or 1,8m dish for good reception
As mentioned above accurate pointing is critical, much more than when receiving L band

@DSP Engr - I have the Titaniun PPL but have always used the scalar rings with my 1.1m dish, I'll have to try without and see if I get a stronger signal - thanks for the tip 
This is my setup https://flic.kr/p/2dpCM3Y

Paul

Ron Liekens
 

Can the Bullseye 10 kHz also be used? It has a 25 mHz input already on board for stability from a GPS timebase.
https://othernet.is/products/bullseye-10-khz-ultra-high-stability-universal-lnb

73' Ron
ON2RON

Paul Gulliver
 

Ron,
No, you need a C band LNB. The item you linked to is not C band, most use the Titanium LNB mentioned above  https://www.titaniumsatellite.com/products#!/C1W-PLL-C-band-LNBF-Wideband-3-4-4-2GHz/p/33208545/category=6743545

Paul

Ron Liekens
 

Thanks Paul ;-)

Ron

DSP Engr
 

Paul,

I tried here on 4F3 with and without the scalar ring feed. It worked better for me without it. I had discussed what I was working on with an engineer at Titanium, before I purchased the CW1-PLL. That engineer is the one who recommended not using the scalar ring with a 1m reflector. I had also separately purchased an offset feed to adapt to the CW1-PLL, and with a 1m offset dish, it worked better without that offset feed addition as well. For larger reflector dishes, the added attachments likely help, but with a small dish, I found that the CW1-PLL by itself worked best. I also note that without the scalar ring, the area of the opening on the CW1-PLL is about the same as the area of the front of the ku band LNBF that came with the dish reflector I am using, so being that the focal area of the 1m dish is optimized for the ku Band LNBF, then the C-band LNBF having roughly the same input area makes sense for optimization. Let me know what you find in your testing as well. Also, both 3F5 and 4F3 are within line of sight here. I get the C-band 10500 burst signals from 4F3 well here, but do not see them at all on 3F5 on the same frequencies. If you could post an image showing the signals received and frequencies from the CW1-PLL for 3F5 where you are seeing the signals that would be helpful.

Eric F1SMV
 

GM
please Kevin how do you connect sdr with multipsk, just received rspdx and i dont see how connect for drive rx. Thank for your help in advance.

73 Eric F1SMV

Chris van Lint
 

Hi Ron,

From Paul's reply I note that you are located in NL.  My mistake of course, because I should have been able to deduce that from your call sign. Nevertheless an exact location would be useful. It's a pity that I only just now learned of your issue, as I was in Groningen a few months ago, where my son is studying at the RUG and I might have been able to hop onto NS, and pay you a visit to try and get you going.
There is no such thing as "just" a beginner.  Decades ago I was also a beginner and over the years I have slowly enhanced my knowledge and I now receive and decode 17 C-Band aero signals simultaneously (5-10500bps andf12-1200bps and I am still learning something new every day.

To get C-Band aero going you need to get all of your ducks in a row.  If just one component is not exactly right, you may finish up with no usable signal.  The following components have to be functioning correctly:

 - Have the correct C-Band LNB.  Not all LNBs cover the aero band frequencies e.g. the Titanium C1-PLL LNB only tunes down to 3.7 GHz and the aero band covers from 3.6 to 3.629GHz.  The non-Lite version of the Titanium C1W-PLL would be preferable, especially if you are contemplating receiving voice and/or 1200bps signals. Don't get distracted by in-line LNA's or pre-receiver LNA's.  The Titanium LNB has a gain of 65dB and unless your cabling is more than 30m, this is more than adequate.

- Ensure that the LNB is correctly fitted and focused.  Specific hardware is required for off-set dishes and Paul or DSP Eng should be able to give assistance if required.  I myself use a 2m prime focus dish and have no experience with off-set dishes.

 - Make sure the dielectric circular polarisation slab is correctly fitted inside the LNB.

- Ensure the bias-tee supplies the correct voltages to achieve the required polarisation direction.  Be aware that not all LNB manufacturers use the same voltages to achieve polarisation direction and some of them use the reverse of what Titanium uses. Paul should be able to advise what polarisation direction Alphasat uses.  While a linearly polarised LNB will result in 3dB attenuation when receiving a circularly polarised signal, an incorrectly polarised LNB with the slab fitted may be attenuated so badly that you get no signal at all.

 - If your SDR includes a built-in bias-tee, make sure it is turned OFF!

 - Unless you are lucky, the dish will have to be correctly aligned to within 1 degree, both in terms of azimuth and elevation, to get usable signals.  Sometimes you may be lucky and see a steady strong (usually sat-TV) signal to which you can tune and use to make final adjustments.  Remember that although the satellite is geosynchronous, it is not necessarily geostationary and over a period of 24 hours both azimuth and elevation may vary by as much as 3 degrees either way!  This is not a big deal for sat-TV

I use David Taylor's WxTrack program https://www.satsignal.eu/software/wxtrack.htm to determine azimuth and elevation at any particular time. Again check with Paul - he may be able to give you a frequency were you can receive a steady strong signal. Paul is very experienced with the EU aero satellites. With a bit of luck Paul can suggest some frequencies to look for aero signals, as they are usually clustered together.

 - Make sure that your cabling is connecting properly.  When turning the LNB on, you should see a significant increase in the noise floor of the receiver.

 - On your SDR software look for signals between 1.550 - 1.511GHz (3.6 to 3.639GHz actual frequency).

When all of the above elements are correctly implemented, the whole thing should "loopt als een trein"

Furthermore if not already done, consider joining the Planeplotter users group (I am no longer a subscriber), there are a lot of very knowledgeable users in that group.

73, VK4CVL