Spotting military aircraft

[satcom]

This has been well covered on the PP Yahoo group for the last couple of months.
There appears to be a timing issue with the dongles  making the raw data unuseable.

There is a chance that  this may eventually be resolved.

Meanwhile it will provide BF and BFPlus s     Beamfinding  providing your radar.txt file is accurate

[TTECH]

Ok thanks for explaining.
I am trying to configure Beamfinder but when I open the 'Mode A/C radar pulse intervals' window, there are only yellow dots all in the same pattern.
Is that normal?

[satcom]

I am not sure what the current status is with rtl1090  software
When I last tested it you had to use a separate version for Mode A/C work.

[TTECH]

Okay.
Do you know a good tutorial to set up beamfinder with R820T dongle?

[TTECH]

Here is what I mean:


The RTL1090 software is set to 'Mode-A/C' instead of Mode-S now.

[satcom]

Should look like this

[Attachment deleted by Admin to save file space]

[TTECH]

Indeed.
Any reason for it?

[Bethsalem]

Okay.
Do you know a good tutorial to set up beamfinder with R820T dongle?

You could try these three resources

http://planeplotter.pbworks.com/w/page/62409382/RTL1090

http://www.youtube.com/watch?v=2U4HrK4tuTI

http://www.nicstorey.co.uk/planeplotter/

[TTECH]

Thank you but nothing about Beamfinder
Seems that it's not possible to do it with the dongle.

[Breitling]

Yes, it is possible with the dongle, but I think you have to know some things about all this stuff.

First of all, seeing EVERYTHING flying around you is almost impossible. Only aircrafts equipped with ADS-B system can be directly detected and seen on PlanePlotter. That means most commercial airliners (not all) and just some general aviation aircrafts. ADS-B is not mandatory in Europe for the later.

Mode S transponders does not transmit position info. You need at least 4 different stations detecting the Mode S aircraft to plot it on PlanePlotter using MLAT. You also need that stations in a good geometric location between them in order to get a decent fix. Once again remember Mode S is not mandatory in Europe for general aviation until 2020.

You can attempt to get a Mode S aircraft fix on your own using Beamfinder or Beamfinder Plus S. You need to create a "radar.txt" file with info about the exact location of Mode S radars in your zone and exact rotation speed for each radar. Note I say exact, otherwise results would be erratic. Another detail: to get a fix for an aircraft with an unknown position you need another aircraft with a known position (ADS-B) being interrogated by the same Mode S radar. If your aircraft is the only one in the zone you get nothing.

Aircrafts equipped with standard Mode A-C transponders can be detected with your dongle using Beamfinder Plus, but...:

- You need to add exact info about secondary surveillance radars to your radar.txt file.
- You need to configure RTL1090 to listen Mode A-C signals.
- You need again another known position aircfaft being interrogated by the same SSR as your aircraft.

And finally remember: aircrafts flying areas where the transponder use is not mandatory, could have it switched off or in stand-by position. By no means you can detect them.

[Anmer]

A good summary, thank you.

[satcom]

- You need again another known position aircfaft being interrogated by the same SSR as your aircraft.


BF PLUS [ Mode A/C ] doesn't need a reference a/c , its totally standalone provided the correct radar.txt file is in force.

A couple of years ago the B2 leaving Fairford  after RIAT made the mistake of putting out short bursts  of Mode A , which enabled us to get fixes on its position as it  departed via the Irish Sea.

[TTECH]

Thanks for exlaining.
As I am located in a military CTR zone, I think that a transponder is obligated. Maybe it isn't in the weekend.
I have a few more questions, and the problem isn't solved yet:

1) So Beamfinder Plus is the only method that is independent on other aircrafts & radars. It uses Mode-A/C signals.
Beamfinder and Beamfinder Plus S are dependent on other aircrafts & radars. It uses Mode-S signals.
Am I right here?

2) If the information above is correct, then I prefer using Beamfinder Plus.
Now the problem is that I am trying to configure Beamfinder Plus using the following tutorial:
http://www.coaa.co.uk/bfplustutorial.htm

In the tutorial he says to open the 'Mode A/C radar pulse intervals' window in PlanePlotter.
When you do this, you should get green AND yellow dots, but when I do it, I only get yellow dots:

So I think there is something going wrong. I have set RTL1090 to Mode AC instead of Mode S.

Also, in the tutorial he says to go to 'View > Chart display options > Chart selected Mode-A radar pulse rate'
I can't click on 'Chart selected Mode-A radar pulse rate' because it's greyed out:


RTL1090 window:


I hope we can solve the problem.

Regards,
Tibo

[Breitling]

- You need again another known position aircfaft being interrogated by the same SSR as your aircraft.


BF PLUS [ Mode A/C ] doesn't need a reference a/c , its totally standalone provided the correct radar.txt file is in force.

Thanks for clarifying. But now I don't understand what is the reference to determine the angular position of the radar head in a given time.

[Breitling]

Also, in the tutorial he says to go to 'View > Chart display options > Chart selected Mode-A radar pulse rate'
I can't click on 'Chart selected Mode-A radar pulse rate' because it's greyed out:

My experience says that if you don't receive enough valid signals, PP won't let you view the intervals nor logging them. But any more authorized voice on PP will explain you better than me.