Tag Archives: spacecraft

Jul 24 2020

Ofcom statement on 5725-5850 MHz

On Friday, July 24, Ofcom released their statement on 5725-5850 MHz and 5925-6425 MHz.

The main points are:
• Make 5925-6425 MHz available for Wi-Fi and other RLAN technologies
• The release of this spectrum will also enable very low power (VLP) outdoor use
• Remove the Dynamic Frequency Selection (DFS) requirements from channels used by Wi-Fi in the 5725-5850 MHz Amateur and Amateur Satellite Service allocation

The Amateur Satellite Service weak-signal downlink band, 5830-5850 MHz, is used by amateur payloads on Deep-Space and Interplanetary spacecraft as well as by satellites in Low Earth Orbit (LEO). Increased use of Wi-Fi across these frequencies could obliterate the weak amateur satellite signals.

Ofcom statement
https://www.ofcom.org.uk/consultations-and-statements/category-2/improving-spectrum-access-for-wi-fi

In 2013 CEPT looked at increased use of 5725-5850 MHz
https://amsat-uk.org/2013/08/29/cept-considers-use-of-5830-5850-mhz-satellite-band/

Wi-Fi Channels in the 5 GHz Band

Jul 10 2020

LunART- Lunar Amateur Radio Transponder

LunART

The European Space Agency (ESA) website has published a proposal by radio amateurs from AMSAT-DL for LunART (Lunar Amateur Radio Transponder): a Communications Platform on the Large European Lander to support communication and payload experiments.

Peter Gülzow DB2OS and Matthias Bopp DD1US say a LunART Communications Platform on the Large European Lander will support direct communication with earth through amateur radio frequencies in the microwave bands, support University and Student Payloads with direct access to their experiments, allow Radio Science for a huge community of radio amateur operators and scientists worldwide. It would also provide an important back-up communication capability and capacity during emergency or when ESA network is busy, for example during non-critical times.

Read the proposal at https://ideas.esa.int/servlet/hype/IMT?userAction=Browse&templateName=&documentId=81f70b2b01f6993c1b76fb6b572ee6c5

Jul 9 2020

LO-94 Amateur Radio in Lunar Orbit

Longjiang-2 / LO-94 in Lunar Orbit

Longjiang-2 / LO-94 in Lunar Orbit

Nature carries an article about the spacecraft Longjiang-2 / Lunar-OSCAR 94 (LO-94), built by students at the Harbin Institute of Technology, that carried the first Amateur Radio communication system to operate in lunar orbit.

As a part of China’s Chang’e-4 lunar far side mission, two lunar microsatellites for low frequency radio astronomy, amateur radio and education, Longjiang-1 and Longjiang-2, were launched as secondary payloads on 20 May 2018 together with the Queqiao L2 relay satellite.

On 25 May, 2018, Longjiang-2 successfully inserted itself into a lunar elliptical orbit of 357 km × 13,704 km, and became the smallest spacecraft which entered lunar orbit with its own propulsion system. The satellite carried the first amateur radio communication system operating in lunar orbit, which is a VHF/UHF software defined radio (SDR) designed for operation with small ground stations.

This article describes and evaluates the design of the VHF/UHF radio and the waveforms used. Flight results of the VHF/UHF radio are also presented, including operation of the radio, performance analysis of downlink signals and the first lunar orbit UHF very-long-baseline interferometry (VLBI) experiment.

Read the article at https://www.nature.com/articles/s41467-020-17272-8

Cartoon movie – Longjiang-2 / LO-94: Journey to the Moon
https://amsat-uk.org/2020/06/06/longjiang-2-lo-94-journey-to-the-moon/

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

Nov 21 2018

ESEO launch information and Dashboard

ESEO satellite in the anechoic chamber at the ESTEC test facilities, in the Netherlands

ESEO satellite in the anechoic chamber at the ESTEC test facilities, in the Netherlands

The launch of the ESEO spacecraft on board the SSO-A flight from Vandenberg is scheduled for 18:31:47 GMT on Monday, December 3.

The ESEO microsatellite includes a FUNcube payload which will provide similar telemetry to its predecessors but will have a more powerful transmitter and thus be even easier to hear. For amateurs, this payload will also provide a single channel L/V transponder for FM. These downlinks will be transmitted on 145.895 MHz and the FM transponder uplink will be on 1263.5 MHz with a 67 Hz PLL tone required.

A new Dashboard has been developed for this mission and is available for download ESEO Dashboard ver 1177

The AMSAT FUNcube Payload Downlink Data document gives all the information required to decode the telemetry ESEO_Downlink_Data_1_21a

The new Dashboard will operate in exactly the same manner as those developed for previous missions and general set-up information can be downloaded here: Dashboard Guidance

A new Data Warehouse has also been created. This can be used to view the telemetry from ALL of the FUNcube missions: http://data.amsat-uk.org/

We expect that the FUNcube telemetry transmitter will become operational after the launch and subsequent to the completion of initial de-tumbling of the spacecraft.

Thanks for your valuable support for this mission!

More information on ESEO is available from ESA Education’s website
https://www.esa.int/Education/ESEO

Information on other SSO-A spacecraft with amateur radio payloads
https://amsat-uk.org/2018/11/14/ssoa-amateur-radio-satellites/

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/