Tag Archives: WSJT

Aug 15 2021

Guide to using FT4 on satellites

Setup for FT4 on the RS-44 satelliteAMSAT-SM have published a guide to using the popular digital mode FT4 via the amateur radio satellites using SDR-Console software, a SDR receiver and the Icom IC-705 as the transmitter.  We have also had information from Jef ON8NT of the setup that he and Thierry ON2ACO used.

The AMSAT-SM guide covers:

• Step 1 – Setup SDR-Console and IC-705 with correct frequency

• Step 2 – Config WSJT-X

• Step 3 – Start Satellite External Radio in SDR-Console

• Step 4 – Select correct RX frequency in SDR-Console

• Step 5 – Find yourself on the satellite transponder

• Step 6 – Start calling CQ

• How to use a 2nd instance of WSJT-X for RX of your own FT4 signal

Read the guide at https://www.amsat.se/2021/08/15/ft4-via-satellite-with-sdr-console-and-ic-705/

This is a short video of FT-4 communication via satellite AO-73 with SDR-Console V3.1 and Icom IC-705. It is a part of a guide that will be published later on AMSAT-SM web https://www.amsat.se/

In the first part you will see the first screen with SDR-Console with Airspy Mini as receiver, audio is piped to WSJT-X. You will also see SDR-Console handle the TX Doppler correction for the IC-705 via “External radio”.

In the second part you will see the second screen with WSJT-X connected to IC-705. The output was only one (1) to two (2) watts! You can see that WSJT-X is reading the Doppler corrected frequency. You will also see SDR-Console satellite tracking and PstRotator controlling the SPID RAS rotor.

Watch FT4 via AO-73 with SDR-Console and Icom IC-705

Thierry ON2ACO and Jef ON8NT use the ICOM IC-9700 for FT4 on the satellites.

They used the video from NU1U on YouTube which gives a good step by step ‘how-to’.

Watch IC-9700 using SatPC32 and WSJT-X

Instead of SatPC32 they used the S.A.T. controller from http://csntechnologies.net/sat

For configuring the RX instance from WSJT-X, also the article from GM4FVM on using multiple instance was very helpful in setting up the soundcard properly in WSJT-X !
See https://gm4fvm.blogspot.com/2021/02/multiple-instances-of-wsjt-x-using-more.html

Jun 6 2020

Longjiang-2 / LO-94: Journey to the Moon

Longjiang-2 / LO-94 in Lunar Orbit

Longjiang-2 / LO-94 in Lunar Orbit

A cartoon movie has been made that tells the story of the student-built spacecraft Longjiang-2 / Lunar-OSCAR-94 which went into lunar orbit and transmitted SSDV images back to radio amateurs on Earth.

SSDV image of Moon and Earth taken by LO-94 (Longjiang-2) - Credit Cees Bassa

SSDV image of Moon and Earth taken by LO-94 (Longjiang-2) – Credit Cees Bassa

Longjiang-2 / LO-94, developed by students and researchers at the Harbin Institute of Technology, is the world’s smallest spacecraft to enter lunar orbit independently. It was launched on May 20, 2018 and radio amateurs tracked its progress as it traveled towards the Moon and successfully entered lunar orbit.

The spacecraft transmitted signals back to Earth on 435.400 and 436.400 MHz. The amateur radio mode SSDV (Slow Scan Digital Video) was used to send back pictures of the Moon and WSJT JT4G was used for messages.

Two VHF/UHF SDR transceivers onboard were used to provide the beacon, telemetry, telecommand, digital image downlink and a GMSK-JT4 repeater, transmitting power was about 2 watts.

Watch Longjiang-2: Journey to the Moon

Harbin Institute Of Technology Amateur Radio Club BY2HIT
Weibo: http://www.weibo.com/by2hit
QRZ: http://www.qrz.com/db/BY2HIT

Oct 24 2018

LO-94 spacecraft signal decoded after bouncing off Moon

SSDV image of Moon and Earth taken by LO94 (DSLWP-B) - Credit Cees Bassa

SSDV image of Moon and Earth taken by LO-94 (DSLWP-B) – Credit Cees Bassa

Daniel Estévez EA4GPZ / M0HXM reports decoding a JT4G amateur radio signal from the LO-94 (DSLWP-B) spacecraft that was reflected off the Moon.

Daniel says “JT4G is a digital mode designed for Earth-Moon-Earth microwave communications, so it is tolerant to high Doppler spreads. However, the reflections of the [DSLWP-B] B0 transmitter at 435.4 MHz, which contained the JT4G transmissions, were very weak, so I had not attempted to decode the JT4G Moonbounce signal.”

However, by analysing a recording made on October 19, 2018 at 17:53:35 GMT he was able to decode one of the five JT4G transmissions in the recording.

Read his blog post at https://destevez.net/2018/10/dslwp-b-jt4g-decoded-via-moonbounce/

Also see Geometry for DSLWP-B Moonbounce
https://destevez.net/2018/10/geometry-for-dslwp-b-moonbounce/

The DSLWP amateur radio satellites built by students from the Harbin Institute of Technology was launched to Lunar orbit on May 20, 2018
https://amsat-uk.org/2018/05/19/dslwp-satellites-lunar-orbit/

May 19 2018

DSLWP amateur radio satellites launched to Lunar orbit

Hu Chaoran BG2CRY tests 435/2250 MHz dish feed for DSLWP ground station - Image credit Wei Mingchuan BG2BHC

Hu Chaoran BG2CRY tests 435/2250 MHz dish feed for DSLWP ground station – Image credit Wei Mingchuan BG2BHC

DSLWP is a lunar formation flying mission led by Harbin Institute of Technology for low frequency radio astronomy, amateur radio and education. It consists of a pair of 47 kg microsatellites launched from the Xichang Space Center into a lunar transfer orbit at 21:28 GMT on Sunday, May 20, 2018 and they will enter a 300 x 9000km lunar elliptical orbit. Onboard each satellite, there are two VHF/UHF SDR transceivers to provide beacon, telemetry, telecommand, digital image downlink and a GMSK-JT4 repeater. Onboard transmitting power is about 2 watts.

Update May 21, 2018: After deployment signals from the DSLWP satellites were received by Edson Pereira PY2SDR, Nicolás Castro CD3NDC, Robert Mattaliano N6RFM and many other radio amateurs around the world.

Chen Yue with 435/2250 MHz feed for the 12m dish at the DSLWP ground station - Image credit Wei Mingchuan BG2BHC

Chen Yue with 435/2250 MHz feed for the 12m dish at the DSLWP ground station – Image credit Wei Mingchuan BG2BHC

Wei Mingchuan BG2BHC reports the first launch window will open at about 21:28 GMT Sunday, May 20. The transmitters will be activated soon after separation. Satellite A will transmit 500 baud GMSK with 1/4 turbo code on 435.425 MHz and 250 baud GMSK with 1/2 turbo code and precoder on 436.425 MHz, and satellite B will transmit 500 baud GMSK with 1/4 turbo code on 435.400 MHz and 250 baud GMSK with 1/2 turbo code and precoder on 436.400 MHz, in every 5 minutes by default. Each transmission will last about 16 seconds. Radio amateurs in South America will have the earliest chance to receive the signals from the satellites, then North America, Oceania, Asia, Europe and Africa.

Harbin Institute of Technology Amateur Radio Club expects radio amateurs to join in this mission. We will prepare different QSL cards for different flight phase for amateurs successfully made QSO or received telemetry. Awards will also be given to the first 10 amateurs in each continent who successfully decoded the signals from the satellites, received the most number of packets, or received an image. Your participation will also help the team to get a better knowledge of the status of the satellites.

An open source decoding software based on GNU Radio to work with RTL-SDR and USRP is provided. Not difficult to change the grc files to support other SDR receivers. A small proxy software will send the decoded data to a server for real-time display.

IARU frequency coordination page:
http://www.amsatuk.me.uk/iaru/finished_detail.php?serialnum=530

Link budgets: http://lilacsat.hit.edu.cn/wp/?page_id=676

Decoder (GNU Radio OOT module): https://github.com/bg2bhc/gr-dslwp

Decoder (Linux Live CD): https://1drv.ms/u/s!Av6J6WjI3UbMhHm8gwMr4Z_keqWH

TLE: http://lilacsat.hit.edu.cn/tle/dslwp.txt

DSLWP-A Telemetry Display: http://lilacsat.hit.edu.cn/dashboard/pages_en/telemetry-a.html

DSLWP-B Telemetry Display: http://lilacsat.hit.edu.cn/dashboard/pages_en/telemetry-b.html

Wei Mingchuan BG2BHC Bug Fix 2018-05-20-1728-GMT: (Check BG2BHC Twitter feed for any further updates)

Sorry to find a bug in the DSLWP live cd! This bug will make the upload of data fail, so it is important to fix it. Please close the proxy, open a new terminal, and type in the following commands:

sudo python -m pip uninstall tornado

sudo python -m pip install tornado==4.5.3

The password is lilac
After running these commands, the bug should be fixed.

DSLWP Lunar Satellite

DSLWP Lunar Satellite

Apr 3 2018

DSLWP Lunar Amateur Radio Satellites

Hu Chaoran BG2CRY tests 435/2250 MHz dish feed for DSLWP ground station - Image credit Wei Mingchuan BG2BHC

Hu Chaoran BG2CRY tests 435/2250 MHz dish feed for DSLWP ground station – Image credit Wei Mingchuan BG2BHC

Two microsatellites DSLWP-A and DSLWP-B carrying amateur radio payloads are planned to launch with the Chang’e 4 Relay satellite on a CZ-4C from the Xichang Space Center into lunar orbit early Monday, May 21 Beijing time (2130 GMT May 20).

Chen Yue with 435/2250 MHz feed for the 12m dish at the DSLWP ground station - Image credit Wei Mingchuan BG2BHC

Chen Yue with 435/2250 MHz feed for the 12m dish at the DSLWP ground station – Image credit Wei Mingchuan BG2BHC

Wei Mingchuan BG2BHC reports DSLWP is a lunar formation flying mission for low frequency radio astronomy, amateur radio and education, consists of two microsatellites.

Developed by students at the Harbin Institute of Technology the amateur radio payload onboard DSLWP-A1 will provide telecommand uplink and telemetry / digital image downlink. An open telecommand is also designed to allow amateurs to send commands to take and download an image.

The satellites are 50x50x40 cm with a mass of about 45 kg and are 3-axis stabilized. Two linear polarization antennas are mounted along and normal to the flight direction.

The downlinks for DSLWP-A1 are 435.425 MHz and 436.425 MHz while downlinks for DSLWP-A2 are 435.400 MHz and 436.400 MHz using 10K0F1DCN or 10K0F1DEN. Will use 250/500 bps GMSK with turbo code or JT4G. Uplinks are reported to be in the 144 MHz band.

Nico PA0DLO says the two satellites, (also known as LongJiang 1 and 2) are planned to perform formation flying in a high elliptical orbit around the Moon (300 x 9000 km).

After launch it will take about 4 and a half days to reach the Moon. This GMAT script should work well for the first days after launch
https://hamsat1.home.xs4all.nl/LongJiang_NYC.script

The groundstation used in this script is a random location in New York City. You can change this to your location by updating the values under the GroundStation tab in GMAT.

DSLWP Radio Information http://lilacsat.hit.edu.cn/wp/?page_id=844

Harbin Institute Of Technology Amateur Radio Club BY2HIT
Weibo: http://www.weibo.com/by2hit
QRZ: http://www.qrz.com/db/BY2HIT
Web in Google English: http://tinyurl.com/BY2HIT

Wei Mingchuan BG2BHC
https://github.com/bg2bhc/
https://twitter.com/bg2bhc

IARU Amateur Satellite Frequency Coordination pages http://www.amsat.org.uk/iaru/

DSLWP Lunar Satellite

DSLWP Lunar Satellite

Aug 11 2014

Ham radio goes around the Moon

Full Moon 2010 - Credit Gregory H Revera

Full Moon 2010 – Credit Gregory H Revera

Towards the end of the year radio amateurs will have the opportunity to receive what must be the ultimate DX from a ham radio payload transmitting the data mode JT65B as it flies around the Moon.

Beijing plans to send a lunar orbiter around the Moon carrying a 14 kg battery powered payload known as 4M-LXS which was developed at LuxSpace. The amateur radio payload will transmit a JT65B signal on 145.990 MHz which can be decoded by radio amateurs using the free WJST software.

The orbiter is one of the test models for Beijing’s new lunar probe Chang’e-5, which will be tasked with landing on the moon, collecting samples and returning to Earth. The launch, planned for 4th quarter 2014, is aimed at testing the technologies that are vital for the success of Chang’e-5. The orbiter will be launched into Lunar Transfer Orbit (LTO) then will perform a flyby around the Moon and re-enter the Earth’s atmosphere after 9 days.

Delivery convoy - Image credit Xinhua

Delivery convoy – Image credit Xinhua

The orbiter arrived by air in Xichang, Sichuan on Sunday, August 10 and was then transported to the Xichang Satellite Launch Center.

Beijing to test recoverable moon orbiter
http://news.xinhuanet.com/english/china/2014-08/10/c_133546027.htm

IARU Satellite Frequency Coordination Pages http://amsat.org.uk/iaru

Free WSJT Software http://physics.princeton.edu/pulsar/K1JT/