Difference between revisions of "GRAPT/RF Validation"

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(2009-07-10)
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* Turnstile antenna
+
* Turnstile antenna (or arrow)
 
* USRP with TVRX
 
* USRP with TVRX
 
* [http://gnuradio.org/trac/browser/gnuradio/trunk/gnuradio-examples/python/usrp/usrp_wxapt_rcv.py WXAPT example] from GNU Radio
 
* [http://gnuradio.org/trac/browser/gnuradio/trunk/gnuradio-examples/python/usrp/usrp_wxapt_rcv.py WXAPT example] from GNU Radio
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* gr_rational_resampler_base_* in C++ (see under filters)
 
* gr_rational_resampler_base_* in C++ (see under filters)
 
* GRC has both blocks? Have to find out about it.
 
* GRC has both blocks? Have to find out about it.
 +
 +
== 2009/09/16 ==
 +
 +
* Followed a NOAA-17 pass (max el 18 °). Very good SNR between 20-30 dB.
  
 
== Lessons Learned ==
 
== Lessons Learned ==

Revision as of 19:35, 16 September 2009

GRAPT Overview



  • Turnstile antenna (or arrow)
  • USRP with TVRX
  • WXAPT example from GNU Radio

This experiment is trivial, nonetheless it validates the RF-part of the setup. It will also reveal whether additional hardware like LNA is required.


Contents

Frequencies

Currently, following NOAA satellites are active on 137 MHz APT and 1.7 GHz HRPT:

SAT APT Freq HRPT Freq Notes
NOAA-15 137.5000 MHz 1702.5 MHz VTX-1 / STX-2 / MSB / OMNI=RCP
NOAA-16 OFF 1702.5 MHz — / STX-2 / MSB / LCP
NOAA-17 137.6200 MHz 1698.0 MHz VTX-2 / STX-1 / LSB / RCP
NOAA-18 137.1000 MHz 1707.0 MHz VTX-1 / STX-3 / HSB / RCP
NOAA-19 137.9125 MHz 1698.0 MHz VTX-2 / STX-1 / LSB / RCP

Source: NOAASIS Satellite Status Information


Passes

Considering a time window of 24h starting at 10:00 UTC on Sat 13 June, there are many potentially useful passes.

NOAA passes occuring between 2009/06/13 10:00 – 2009/06/14 10:00 UTC


We only need a few good passes for successful experiment and they should be distributed over time in order to allow debugging and problem fixing between the passes.

2009-06-11

  • Created this page preparing for the experiment to be carried out during the weekend 13-14 Jun 2009.
  • Need to upgrade laptops and install recent GNU Radio

2009-06-12

  • Upgraded laptops to Ubuntu 9.04 and GNU Radio 3.2
  • Problems with example APT receiver since it uses 32k audio but my crap HW can only do 44k1 or 48k.

2009-06-13

  • I realized that I brought a BNC male/male adapter instead of a female/female that I need to connect my antenna to the TVRX. Experiment postponed!

2009-07-04

2009-07-10

  • Found out that there are resampler blocks in GNU Radio - very efficient ones indeed!
  • blks2.rational_resampler_* for Python
  • gr_rational_resampler_base_* in C++ (see under filters)
  • GRC has both blocks? Have to find out about it.

2009/09/16

  • Followed a NOAA-17 pass (max el 18 °). Very good SNR between 20-30 dB.

Lessons Learned

  1. Do not pack your gear in a hurry.
  2. RTFM (RE: resampling audio) — also the examples!



GRAPT Overview