Receiving satellites

There are several weather satellites which are in a polar orbit. That means they are going from pole to pole and the earth is moving below them and this way they can visit the complete surface of the earth within a few days. And the best thing is they are sending unencrypted data back to earth in form of pictures from the surface.

The NOAA satellites are the most famous ones, but there are others like MetOp and FengYun. The NOAA satellites are using the APT (Automatic Picture Transmission) in the 2m band and HRPT (High Resolution Picture Transmission) at 1,7GHz. The MetOP and FengYun satellites use only HRPT at 1.7GHz. Check out the Frequencies page for a comprehensive list of the used frequencies.

To receive the data send by the satellites you need only a RTL-SDR stick and a helix antenna. The HRPT can be a bit difficult as 1.7GHz is near the upper limit of the RTL-SDR stick, but it should work. The helix antenna is easy to build.

Link list: – Rechner für QFH Antennen – HRPT specification – HRPT Decoder software - Guide for HRPT

StratoSat TK1 435.870MHz


POCSAG is the protocol used for the pager networks.

There are several commercial providers and with DAPNET exists a network for ham radio.


The used frequency for DAPNET in Germany is 439.9875 MHz (

Easiest way to use DAPNET is to host a transmitter with a MMDVM HotSpot Board ( with PI-Star ( on a Raspberry Pi Zero.

If no pager hardware is available a rtl sdr can be used.

Use GQRX as the receiver and forward the POCSAG signal to multimon-ng: nc -l -u -p 7355 | sox -t raw -esigned-integer -b 16 -r 48000 - -esigned-integer -b 16 -r 22050 -t raw - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 -f alpha -

This a version which should work without GQRX but is not tested and frequency has to be adjusted to Germany ( rtl_fm -M fm -f 439.9875M -s 22050 -g 100 -l 310 | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 /dev/stdin

For test purposes you can send a POCSAG message locally from the pi-star system: sudo RemoteCommand page ” ( - Nachrichtenaufbau von POCSAG - Nachrichtenaufbau von POCSAG


144.8 MHz APRS Frequenz in Europa 432.5 MHz APRS Frequenz in Europa

439.9875 MHz DAPNET (POCSAG) Frequenz


Relais Stuttgart 70cm 438.56250 (DB0LBG) at Katharinenlinde, Sightseeing Tower, DE. –

Relais Hannover 70cm DB0FUS 439,200 MHz –

Relais Hannover 70cm DB0TVH 439.2375 MHz – Bredero-Hochhaus –

438,337,5 MHz DMR+-Relais DB0LBG am Kathrinen-Linden-Turm

WSPR frequencies

Satelitte frequencies







AHRPT: 1707mhz


AHRPT: 1701.3mhz


CHRPT: 1704.5mhz


CHRPT: 1698mhz

StratoSat TK1 435.870MHz

137,563200 LSB USB Hannover Information Wetter, Zeit

440,9386 MhZ Packet radio Hannover

439.862 mhz



SDR – SDR Software

Digitale Betriebsarten – WSJT Homepage Software für WSPR und andere Betriebsarten

Satelittenfunk – gpredict

Digital Modes - A Digital Voice mode for HF radio



CW – Python CW generator


RDS – RDS decoder software – Receive rds with redsea – meshed routing protocol – python babel Implementierung – TNC software – radioircd irc server

Github Repos

Link Collection


Speziell - Database of relais stations worldwide - Weak signal communication - Alan’s Lab - some amateur radio projects - mcHF QRP transceiver - Small and inexpensive homebrew HF radio - The N6QW blog collects and shares bits of information on one ham’s homebrewing activities - Codec 2 - A free speech codec - Open Source für Funkamateure – Kabelbelegung Baofeng – Kabelbelegung Baofeng 2 – Kabelbelegung Baofeng 3 – Headset Pinbelegung Baofeng – Antennensteuerung – Rechner für QFH Antennen – QFH Antenna building guide – DAPNET ein Hampager Netzwerk – Solar Data Banners & Widgets – Amateurfunk Relaisinteressengemeinschaft Mittlerer-Neckar e.V.