Boris Maryshev wrote: > Great news indeed, but still no code in svn? Hello,
I am planning post-Dayton for svn. Things are not complete. I got some panel mount N connectors and made up a simple 1/4 wave groundplane for 1090 MHz. I tie-wrapped a 40 foot or so extending tent pole to my back deck and was able to go 10 feet above the Discone. The 1/4 wave on the pole added about 20 miles of range over the Discone. I also tried my AOR 5000 with the out-board IF Output amplifier into the LFRX daughterboard and was able to get about 100 mile range on the discone and 120 mile range on the 1/4 wave. I also got some surface position reports from Logan. With Google Earth most of the surface positions were located on Runways. One was in a East Boston neighborhood but it is likely due to INS errors. Most planes takeoff down the centerline of the runway but some are way off. Instead of getting ready for the Dayton trip, I spent yesterday evening using NEC to make a curly coil colinear with 1/4 wave and 5/8 wave elements. I have not built it yet. I implemented the new preamble detection and it works better. I need to do the bit error detect and correction part. I thought I was getting a lot of bit errors on some messages. I reread my background information and found the interrogator id is XOR with the CRC. On other messages the airframe id is XOR with the CRC. Reminds me of RDS used on the FM broadcast band. The ADS-B and ACAS messages have an interrogator id of zero so they are easier to check. I did a quick check of the file generated using the AOR 5000 with the 1/4 wave antenna and found all 15 possible interrogator ids in use. I looked at the all-call replies of a few aircraft and it was not unusual for the transponder to respond to multiple radars. Because I have interest in doing other aircraft receivers, I am thinking of calling the project directory gr_air. I was also thinking about gr_aero but people may mistake it for the Windows Vista video sink. Mode S has a different meaning for the AMSAT crowd so it is not a good choice. 73 Eric _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
