# About the decoding result of gr-air-modes **URL:** \ **Category:** GNU Radio\ **Created:** [May 3, 2014, 3:44pm UTC](https://www.ruby-forum.com/t/about-the-decoding-result-of-gr-air-modes/240863 "2014-05-03T15:44:44Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\ **Post date:** [May 3, 2014, 3:44pm UTC](https://www.ruby-forum.com/t/about-the-decoding-result-of-gr-air-modes/240863/1 "2014-05-03T15:44:44Z")
Hi all, I install the gr-air modes. And the hardware I am using is USRP N210 without GPSDO. The command I am using is the default command of the modes\_rx module. And after I run this module, I got the following Results: (-47 32.32056722) No handler for message type 24 from 739803 (-48 34.25826672) No handler for message type 24 from 207ee9 (-48 35.86728697) Type 5 (short surveillance ident reply) from a49b0c with ident 1264 (SPI ALERT) (-48 35.87198622) No handler for message type 24 from a35558 (-50 35.95602397) No handler for message type 24 from 8b672a (-49 35.97354972) Type 4 (short surveillance altitude reply) from 6e0c4c at 65200ft (AIRBORNE ALERT) (-48 36.32546122) Type 5 (short surveillance ident reply) from 69f33f with ident 5514 (SPI) (-49 37.18337247) Type 0 (short A-A surveillance) from 608e19 at 120900ft (No TCAS) (aircraft is on the ground) (-48 37.21837897) No handler for message type 24 from e80163 (-50 38.68267197) No handler for message type 24 from b3e6f2 (-48 39.26921197) Type 0 (short A-A surveillance) from 12ff05 at 2250ft (speed 600-1200kt) (aircraft is on the ground) (-49 40.52049497) Type 5 (short surveillance ident reply) from 38e9a8 with ident 3576 (SPI) (-48 40.56394397) Type 0 (short A-A surveillance) from cf63e4 at 8700ft (Full TCAS resolution) (aircraft is on the ground) (-47 40.56904497) No handler for message type 24 from 5353ab (-48 41.08549722) No handler for message type 24 from b60846 DD(-48 52.18300072) Type 5 (short surveillance ident reply) from da22a7 with ident 3450 (SPI) (-47 53.62936347) Type 5 (short surveillance ident reply) from 8c773 with ident 3374 (GROUND ALERT) D(-49 56.62670697) Type 0 (short A-A surveillance) from fa024d at 125800ft (speed 1200-2400kt) (-47 56.95657397) Type 5 (short surveillance ident reply) from 3b6a76 with ident 5634 (aircraft is on the ground) (-47 57.34665522) No handler for message type 24 from f9ac8a D(-50 59.47285847) Type 5 (short surveillance ident reply) from 7d6227 with ident 3510 (SPI ALERT) (-51 59.49907272) Type 0 (short A-A surveillance) from 581dfb at 76200ft (No TCAS) (aircraft is on the ground) D(-48 61.03326422) No handler for message type 24 from a90fee (-48 61.18943772) Type 21 link capability report from 18049d: ACS: 0xd0ccc, BCS: 0xfeae, ECS: 0xa7, continues 4 ident 1810 (-49 62.11700572) Type 4 (short surveillance altitude reply) from 62253 at 17325ft (SPI ALERT) (-47 62.44659672) No handler for message type 24 from 27adc7 D(-49 64.96764872) No handler for message type 24 from e30901 (-50 64.98554547) Type 5 (short surveillance ident reply) from a39eee with ident 7306 (SPI ALERT) (-47 65.04707547) No handler for message type 24 from 0ec82e (-49 65.10223472) Type 5 (short surveillance ident reply) from ca6477 with ident 3034 (AIRBORNE ALERT) (-48 66.02713647) No handler for message type 24 from b4567c (-48 66.37042047) No handler for message type 24 from 21544d (-49 66.49397872) No handler for message type 24 from 759628 (-49 66.62760947) No handler for message type 24 from d79b77 (-48 67.58220572) Type 5 (short surveillance ident reply) from 98fb94 with ident 3334 (AIRBORNE ALERT) (-49 68.06558797) No handler for message type 24 from 6d93b5 (-48 68.86033522) No handler for message type 24 from 4cc3fd This is not what I want and I don’t think it is the correct decoding result, is it right? I did this experiments in indoor environment, then I think maybe the signal is too weak, then I move to the corridor and redo this and get similar results. I can not get the position of the air plane. So my question is that, is it all about the environment? Is there any other possible bugs or something I missed that cause the output I’ve received? I am very curious because the corridor is quite close to the out door environment. Thanks a lot. Yaxiong – \*Yaxiong Xie / \*_谢亚雄_ School of Computer Engineering Nanyang Technological University, Singapore ---
**Author:** ![YAXIONG\_XIE](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/8edcca/32.png) [@YAXIONG\_XIE](https://www.ruby-forum.com/u/YAXIONG_XIE)\ **Post date:** [May 4, 2014, 10:03am UTC](https://www.ruby-forum.com/t/about-the-decoding-result-of-gr-air-modes/240863/2 "2014-05-04T10:03:54Z")
Do you get the GPS location of the air plane? Or do you get it before? If it is not the radio or antenna, maybe the environment matters? I didn’t do any experiments in a totally open area, so I don’t know whether it works under that scenario. If we can decoding the signal in environment, I think it should be very useful. Yaxiong 2014-05-03 21:54 GMT+08:00 Silverfox [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid): > Hi all, > > at 65200ft (AIRBORNE ALERT) > > D(-49 64.96764872) No handler for message type 24 from e30901 > > signal is too weak, then I move to the corridor and redo this and get > > School of Computer Engineering > > Nanyang Technological University, Singapore – \*Yaxiong Xie / \*_谢亚雄_ School of Computer Engineering Nanyang Technological University, Singapore