Difference between revisions of "GRAPT/RF Validation"

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* Turnstile antenna
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* 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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''Source: [http://noaasis.noaa.gov/NOAASIS/ml/status.html NOAASIS Satellite Status Information]''
 
''Source: [http://noaasis.noaa.gov/NOAASIS/ml/status.html NOAASIS Satellite Status Information]''
  
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'''TODO:''' METEOR, [http://en.wikipedia.org/wiki/MetOp MetOp] and [http://en.wikipedia.org/wiki/NPOESS NPOESS]?
  
 
== Passes ==
 
== Passes ==
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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.
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 +
== 2009-09-16 ==
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* Followed a NOAA-17 pass (max el 18°) using USRP+TVRX+Arrow. Very good SNR between 20-30 dB.
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== 2009-10-10 ==
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Received NOAA-15 using turnstile, USRP+TVRX. Good signal but lost quickly. The antenna is definitely worse than the arrow.
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[[Image:NOAA15-20091010_174619.png|300px]]
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== Lessons Learned ==
 
== Lessons Learned ==

Latest revision as of 17:58, 10 October 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.


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

TODO: METEOR, MetOp and NPOESS?

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°) using USRP+TVRX+Arrow. Very good SNR between 20-30 dB.

2009-10-10

Received NOAA-15 using turnstile, USRP+TVRX. Good signal but lost quickly. The antenna is definitely worse than the arrow.

NOAA15-20091010 174619.png


Lessons Learned

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



GRAPT Overview