Share your results

Discuss KerberosSDR - 4x Coherent RTL-SDR
rtlsdrblog
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Re: Share your results

Post by rtlsdrblog » Fri Apr 19, 2019 3:22 am

Duppo wrote:
Thu Apr 18, 2019 7:11 pm
On which side channel 1 should be on ULA? Its not numbered on the picture. I mean should channel 1 be most left or most right of the antennas?
Channel 1 is on the left with the unit facing you. Sorry the diagram is a bit difficult to understand. I'll try and fix those up soon.

Duppo
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Joined: Thu Apr 18, 2019 7:10 pm

Re: Share your results

Post by Duppo » Fri Apr 19, 2019 11:46 am

Duppo wrote:
Thu Apr 18, 2019 7:11 pm
On which side channel 1 should be on ULA? Its not numbered on the picture. I mean should channel 1 be most left or most right of the antennas?
rtlsdrblog wrote:
Fri Apr 19, 2019 3:22 am
Duppo wrote:
Thu Apr 18, 2019 7:11 pm
On which side channel 1 should be on ULA? Its not numbered on the picture. I mean should channel 1 be most left or most right of the antennas?
Channel 1 is on the left with the unit facing you. Sorry the diagram is a bit difficult to understand. I'll try and fix those up soon.
thank you for information, managed to get pretty accurate location with android app!
Just a tip for people locating signals in city areas: for me best solution was first to drive around a bit with signal direction logging on to get general direction of signal (rough estimate) then drive around the rough area and turning the direction finding on for 10 seconds - switching area and direction turn it on for 10 seconds again. after repeating this approx 7 times i got location of GSM antenna within 10 meter accuracy

rtlsdrblog
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Re: Share your results

Post by rtlsdrblog » Fri Apr 19, 2019 1:19 pm

Nice and good tips too. Yeah you need to get readings at a few locations to really get a good idea of where the TX is. Can we see a screenshot of your app results if it doesn't give away too much info?

Duppo
Posts: 14
Joined: Thu Apr 18, 2019 7:10 pm

Re: Share your results

Post by Duppo » Fri Apr 19, 2019 2:55 pm

rtlsdrblog wrote:
Fri Apr 19, 2019 1:19 pm
Nice and good tips too. Yeah you need to get readings at a few locations to really get a good idea of where the TX is. Can we see a screenshot of your app results if it doesn't give away too much info?
Sure, here's imgur link for gallery of 2 pictures

https://m.imgur.com/a/CQJ1B3d

More info: GSM antenna is located in centre of town on top of regular apartment building, a lot of height difference and other buildings around. It can be seen on pictures that there is alot of "false" lines from reflections most likely but after couple of measurements from different angles it was really easy to pinpoint location of the antenna even in not ideal conditions.

rtlsdrblog
Site Admin
Posts: 2273
Joined: Mon Nov 19, 2012 11:54 pm

Re: Share your results

Post by rtlsdrblog » Sun Apr 21, 2019 12:11 pm

Duppo wrote:
Fri Apr 19, 2019 2:55 pm
rtlsdrblog wrote:
Fri Apr 19, 2019 1:19 pm
Nice and good tips too. Yeah you need to get readings at a few locations to really get a good idea of where the TX is. Can we see a screenshot of your app results if it doesn't give away too much info?
Sure, here's imgur link for gallery of 2 pictures

https://m.imgur.com/a/CQJ1B3d

More info: GSM antenna is located in centre of town on top of regular apartment building, a lot of height difference and other buildings around. It can be seen on pictures that there is alot of "false" lines from reflections most likely but after couple of measurements from different angles it was really easy to pinpoint location of the antenna even in not ideal conditions.
Nice results, thanks for sharing! You could also try a circular array. When you can get multiple readings in a car, the circular array can work quite well.

Duppo
Posts: 14
Joined: Thu Apr 18, 2019 7:10 pm

Re: Share your results

Post by Duppo » Mon Apr 22, 2019 8:49 am

In following days I will try circular array once I receive magnetic mount antennas. Currently I'm using dipole kits from rtl sdr shop. They work really work for linear array and are good bang for buck, but I assume it's not possible to mount them in circular array on car windshield as its tilted.

Also has anyone tried passive radar? I would love to see results!

253flo
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Joined: Mon Apr 22, 2019 6:20 pm

Re: Share your results

Post by 253flo » Mon Apr 22, 2019 6:24 pm

Has anyone done any range testing with their setup?

Duppo
Posts: 14
Joined: Thu Apr 18, 2019 7:10 pm

Re: Share your results

Post by Duppo » Wed Apr 24, 2019 7:47 pm

Tried today circular array on known signal using rtl sdr dipoles.
Small town area so a bit of reflections but overall results are very impressive!

Image

Transmitter location is not marked on picture, but its obviously where lines cross alot 8-)

rtlsdrblog
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Re: Share your results

Post by rtlsdrblog » Thu Apr 25, 2019 1:16 am

Not bad at all! Next steps for the app will be to find an algorithm that can find the center of the cross points.

rtlsdrblog
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Re: Share your results

Post by rtlsdrblog » Thu Apr 25, 2019 5:06 am

By the way, I forgot to mention that if you long press on the map in the Android app you can add a marker to mark the known or suspected location of a TX tower.

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