The Aero Thread..

[s-band]

Ok so as an "amateur" how do I accomplish "locking my receiver to a GPS source"

The Airspy has a 10MHz reference input which makes it easy if you have a reference like the HP Z3816A or similar Z3816A GPS Receiver. The RTL uses a 28.8MHz crystal. I've no experience of them but _Precision Frequency Reference (GPS Clock) [GPS-CLOCK] - 150.00GBP : Leo Bodnar, Simulator Electronics seems to get good comments and has a frequency agile output.

Locking the LNB is covered here C Band LNB Ext Ref Mod - Miscellaneous Projects - Open Source Mobile Communications but the TCXO I used is good enough for me.

I locked a signal generator to a GPS source and used that to do the calibration of the whole chain. Not very amateur though. The simplest way to calibrate a system, without test gear, would be to use one of the C band satellite beacons although I think some can be a few kHz off. You could calibrate you RTL using ham beacons if you are within range. Set the ppm offset in SDR# to give the correct frequency.

 

[Vipersan]

Ok ...and for my next question ..
I guess we can also decode Aero-H signals ...assuming we can receive em ..
I know these signals are approx 1525.0 – 1559.0MHz
I know these signals come from Inmarsat ...?
Which one(s)
I have plans to build a patch antenna for this frequency.
but ...this vid is showing a small satellite dish doing the job ..with what I can only assume is some sort of patch antenna at it's focus ..
S-band can you help ?
I need more information..
Receiving AERO-H on L-band (Inmarsat AOR-W) • /r/RTLSDR
rgds
VS

 

[Confucian]

The Airspy has a 10MHz reference input which makes it easy if you have a reference like the HP Z3816A or similar Z3816A GPS Receiver. The RTL uses a 28.8MHz crystal. I've no experience of them but _Precision Frequency Reference (GPS Clock) [GPS-CLOCK] - 150.00GBP : Leo Bodnar, Simulator Electronics seems to get good comments and has a frequency agile output.

Locking the LNB is covered here C Band LNB Ext Ref Mod - Miscellaneous Projects - Open Source Mobile Communications but the TCXO I used is good enough for me.

I suspect you are right, having read a few articles I think "Try your TCXO route" first. You have about a 10 days to hide while I collect the hardware before I start asking daft questions. lol
Thanks for all of you recent posts they have been very informative and along with a few others have got me from a pile of second parts to a working system.

 

[Confucian]

Ok ...and for my next question ..
I guess we can also decode Aero-H signals ...assuming we can receive em ..
I know these signals are approx 1525.0 – 1559.0MHz
I know these signals come from Inmarsat ...?
Which one(s)
I have plans to build a patch antenna for this frequency.
but ...this vid is showing a small satellite dish doing the job ..with what I can only assume is some sort of patch antenna at it's focus ..
S-band can you help ?
I need more information..
Receiving AERO-H on L-band (Inmarsat AOR-W) • /r/RTLSDR
rgds
VS

Have you seen this one.

I have seen another somewhere showing a dish focusing on a patch antenna as you suggest but cant find it again now.

 

[Vipersan]

yep

Have you seen this one.

I have seen another somewhere showing a dish focusing on a patch antenna as you suggest but cant find it again now.

seen that one before ...
curious tho ...
using a log periodic at that frequency ...
Which as far as I know is for linear reception ...and that surprises me a little ...on account I read somewhere that 99% of L band signals are Circular polarised ..
Which is why I'm going to construct a patch antenna ..
Cheers for reminding me of that vid Confician ..
You can never have too much info...
lol

 

[s-band]

I have seen another somewhere showing a dish focusing on a patch antenna as you suggest but cant find it again now.

on Jonti's JAERO page? JAERO That looks like a simple, cheap method. I'm haven't looked up which way round the polarisation is but he gets it to work both ways since it works with and without the dish, probably due to poor x polar rejection

yep
Which as far as I know is for linear reception ...and that surprises me a little ...on account I read somewhere that 99% of L band signals are Circular polarised ..
Which is why I'm going to construct a patch antenna ..

Yes, they are but it will only lose 3dB. If there is nothing to interfere from the other circular polarisation, it will not matter too much. Log periodics as dish feeds can be problematic as the effective feed point moves along the length of the log periodic with changing frequency. Your patch should be better. Long ago, when the world was analogue, I put a dipole in front of a C band feed to listen to NPR (National Public Radio) which had a permanent transmission on L band Inmarsat.

The log shown may be from Printed Circuit Board Antennas| Commercial and Hobby Antennas who does dome very affordable PCB antennas. He also sells PCBs for MMIC amplifiers at 5 for $10 which would be handy for these projects.

This link leads to lots of info inmarsat Archives - rtl-sdr.com including helical antennas and feeds. I used a 4 turn one on S band with an 80cm offset dish. Here's one someone did for Inmarsat Building an L-band helical antenna for Inmarsat - rtl-sdr.com

 

[Vipersan]

Takes a bit of getting ones head around ...but think I'm making some progress ..
Using RTL1090 and Jaero to display both datasets on PP ...
Bit quiet atm ..so not much to see ...but definately 2 sets of planes shown ..
White is C band Jaero ..and Yellow is RTL1090 data ...
rgds
VS

in this demo I'm using an RTL dongle for 1090 and SDRplay for Jaero ...but I have had three SDR receivers running ...with weather data as well ..but sadly Jaero is unreliable then ..
I guess it's just a question of more CPU needed but is theoretically possible ..
rgds
VS

 

[Vipersan]

Hmm ..that didn't work for long ..
Jaero carried on but after placing 3 planes in PP ..RTL1090 crashed ...requiring a PC reboot ..
Could it be the 2 sets of data conflict ?
This is a very steep learning curve..

 

[Vipersan]

So ...how does this actually work I wonder ?
I picked up a Ryanair flight (370) call sign 15CG over the UK woth RTL1090 ...it passed over or close to Manchester from Europe..and headed out to sea ...where it disappeared over Morcambe bay ..?

I would have then expected it to be picked up by Jaero ...as the Cband data is tracked over a longer range ...so further offshore ..but of course if it did land in Ireland ..then short range tracking is all that was neccessary (handed off )..and an RTL1090 system based in say Belfast would have picked it up to see it's journey completed..

I should have taken note where it was headed ..as it may well be destined to land in Ireland ...?

I'll try and pick up a plane taking off from Manchester heading to the USA ..and see if and how far I can track it without losing it ..
Tomorrow that is ..
lol

 

[s-band]

So ...how does this actually work I wonder ?

I can't get on with PP but VRS (Preview edition) works fine. However, it takes an hour+ from loss of mode S to acq of Inmarsat. I set VRS "remove from display" to 3600 sec and "Remove from tracking" to 7200 sec. See the pic here RTL1090 thread the gap between the local and Atlantic shows up. As soon as a plane appears on Inmarsat, the trail joins up to the mode S one. The only problem is that the local trails persist too long.

 

[Analoguesat]

I'll try and pick up a plane taking off from Manchester heading to the USA ..and see if and how far I can track it without losing it ..
Tomorrow that is ..
lol

Several heading west today

0915uk to Vegas.
0925uk to New York

Live Flight Departures | Manchester Airport

 

[Vipersan]

I can't get on with PP but VRS (Preview edition) works fine. However, it takes an hour+ from loss of mode S to acq of Inmarsat. I set VRS "remove from display" to 3600 sec and "Remove from tracking" to 7200 sec. See the pic here RTL1090 thread the gap between the local and Atlantic shows up. As soon as a plane appears on Inmarsat, the trail joins up to the mode S one. The only problem is that the local trails persist too long.

So I take it the version both Llew and I are playing with (VRS) isn't suitable for mode -S and ACARS (Inmarsat) ?
A special ...preview ...version is needed ?
I too prefer VRS to PP now I've tried both ...and if I can get mine to work with both data sets I will be happy ..
rgds

Oh ..and btw AS ...
had I lie in ..and missed both my flights ..
No Vegas for me ...
doh!

 

[s-band]

So I take it the version both Llew and I are playing with (VRS) isn't suitable for mode -S and ACARS (Inmarsat) ?
A special ...preview ...version is needed ?

The normal one works but trails between the 2 clusters are seldom joined. Preview removes the limits on timeouts allowing the trails to join.

A thought - it didn't work to start with because I forgot to set up a "Merged Feed" under "Options" to combine more than one feed on the map.

 

[Analoguesat]

Oh ..and btw AS ...
had I lie in ..and missed both my flights ..
No Vegas for me ...
doh!

Several more heading out west today VS

 

[Confucian]

Thanks to loads of Help and Ideas mainly from this Forum here is my working system.
Monitoring 25E & 54W two T channels on both. Feeding VRS & PP.



The pc is a secondhand Quad Core HP Windows 7 Desktop PC AMD Phenom II x4 3.0GHz 4GB DDR3 RAM 250GB HDD off ebay £94.99
2 RTL-SDR dongles, 2 x SDR#, 2x Jaero (widebandwidth enabled), 1x VRS, 1x PP CPU 60-75%

 

[Vipersan]

Very Very nice buddy ..
I think we all have some catching up to do ...but sadly I never will totally ..on account I cannot dedicate a Cband dish to this full time ..
I do have a spare 1.2m I'm thinking of trying ..but prolly wayyy too small ..
;)
Question tho ..
25E I get but I wasn't even aware we could use 54W ?

So have you 2 large Cband dishes in service ?

 

[Confucian]

Very Very nice buddy ..
I think we all have some catching up to do ...but sadly I never will totally ..on account I cannot dedicate a Cband dish to this full time ..
I do have a spare 1.2m I;m thinking of trying ..but prolly wayyy too small ..
;)
Question tho ..
25E I get but I wasn't even aware we could use 54W ?

So have you 2 large Cband dishes in service ?

I have a friend on another group using a 1.2 Offset on 15W no problem at all.
I'm lucky here in Ireland as during the "Celtic Tiger" years lots of Eastern Europeans came over but wanted to watch TV from their homelands . Now the internet has taken over there are plenty of cheap large dishes about, some need a little TLC but hey.
I picked up 2 x 1.4m offsets €40, 1.8m Prime €50 and 1.2m Prime Stearable €30.
I'm using a 1.4 on 54W good strong signal and 1.8 on 25E not so strong signal but may need more tweeking. Might put other 1.4 on 15W next.

 

[Lazarus]

You lucky, lucky, lucky ......





........ fellow ;)

 

[Vipersan]

Well ...you've inspired me to at least up my game PC wise ..
Just bagged what I hope will do the BIZ ...

for a very reasonable £140 inc delivery ..

I will leave the SDRplay installed in the original Optiplex ...for general DXing and noaa weather sat coverage..
The 990 will then be dedicated to Aero ..with the Airspy when it arrives..
;)

Dell Optiplex 990 SFF PC, 3.1GHz i5-2400 CPU, 8GB RAM, 250GB HDD, DVD, Windows 7

 

[Confucian]

You lucky, lucky, lucky ......





........ fellow ;)

Your right I am so lucky, plenty of space and out in the sticks so little RF interference. In the background of this shot is my 45 foot mast with VHF (airband) and ADSB Antenna, it was 65 foot until the last Atlantic depression passed through. lol I then learnt how to "guy" a mast properly.