HRPT reception

Updated July 2020

Weather satellites transmit High Resolution Pictures at 1.7 GHz. The transmission is not encrypted and all needed is a low noise antenna and LNA , an SDR  and GNU-RADIO or third party software.

The minimal, portable setup regularly in use here is an Airspy Mini , a 40cm diameter helicone on a tripod, a 0.2 dB NF G4DDK LNA  and XHRPT software  .

There are also  GNU Radio scripts available.

Some pictures showing this small portable setup and what it can do , can be found below.

The first picture is from a NOAA15 pass which is the weakest of all NOAA,Metop,FY satellites on L-band.  Second picture is from the strong NOAA19. Third is from a Meteor MN2-2 pass .

 

 

The helicone antenna below has been simulated and optimized in CST Microwave Studio.

The goal was minimum dimensions for acceptable G/T performance.

helicone_40cm

 

All in all, no big antennas are required to get excellent pictures.

Some more details also about the larger antenna I use:

1) For automated tracking and reception the 2.5 m EME dish is used. Rotator is a SPID BIG RAS . The feed  illuminating the dish is a 3 turn helix off-set to the 23cm N2UO/W2IMU feed . Directly attached to the feed is a a slightly modified G4DDK 23cm VLNA (NF=0.2dB)  To protect the L-Band LNA during TX , a low loss PTT-activated coaxial switch is placed in front of the LNA . After the LNA a Lorch 5DF6 band pass filter  suppresses any cellular interference.

But as explained above, the setup can also be lightweight and portable ! Satellites can be tracked by hand as well so I use a small helicone antenna (D=40 cm) on a tripod and a G4DDK LNA directly attached to it. Especially when using a low gain  / low noise antenna like a small helicone it is important to use a really low noise amplifier.

See below 2.5 m dish for moonbounce.

Note: Need to make a nicer, balanced counterweight. That box only was a quick workaround 🙂

dish_july2020

2) Automated tracking is done either with USA_SATCOM’s UltraTrack software or my own  EME FUN software  and the EME FUN antenna controller

3) SDR is an Airspy Mini  or the USRP1 (modified clock 48 MHz,streaming 6 MSPS)

4 ) When I started reception some years ago I used  to use GNU-Radio-based POES-USRP  on Linux . Then found a way to install GNU-Radio (3.6.4.1) on Windows and used the following flowgraph:

Download HRPT GNU-radio companion .grc file from my dropbox .

As of July 2020, I mostly use USA_SATCOM’s excellent XHRPT software on Windows 10 which supports all active weather satellites of interest :  NOAA 15,18,19 / Meteor MN2, MN2-2 and FengYun .

There are also  GNU Radio scripts available.

5) For visualization/false color images I use either David Taylor’s  HRPT reader  or Fred Jansen’s weathersat 

73 de SV1CAL  – Michael Margaras

helicone_mn2_2_g4ddk_xhrpt

 

helicone_noaa19_g4ddk_xhrpt

 

2 thoughts on “HRPT reception”

  1. Very good article. I see that the USRP is using sample rate of 2 MSPS. Would that be means RTL SDR also can be used?

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