Jovian-1 U/V FM Transponder Test

 

2025-07-24 Jovian-1 U/V FM Transpnder

Jovian-1 U/V FM Transponder

David Bowman G0MRF reports the successful on-air test of the AMSAT-UK U/V FM transponder has been carried out.

Jovian-1 U/V FM transponder test siteDestined for the 6U Jovian-1 satellite, this mode U/V FM transponder had its first on-air test on Thursday, July 24, 2025.

A 70cm 20 watts ERP signal was transmitted over a distance of 59 km with a path loss of -150 dB and received by the FM transponder on a QFH antenna. The signal was re-transmitted on 145.895 MHz.

The first contact was between Mike Willis G0MJW and Graham Shirville G3VZV

AMSAT-UK Jovian-1 Announcement September 2024
https://amsat-uk.org/2024/09/29/amsat-uk-new-project-announcement-2/

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Use of 430-440 MHz by AST SpaceMobile constellation

434.100 MHz downlink received September 12, 2024 by PE0SAT

434.100 MHz downlink received September 12, 2024 by PE0SAT

AST & Science LLC (AST SpaceMobile) currently have five Bluebird commercial satellites that use the amateur radio 430-440 MHz band. They were launched into Low Earth Orbit on September 12, 2024.

For an explanation of the problems these satellites cause see this post by AMSAT-DL President Peter Gülzow DB2OS https://community.libre.space/t/asts-bluebird-1-5/12255

Despite not being amateur satellites the first five commercial satellites use these amateur frequencies for telemetry links with a 50 kHz bandwidth: 430.5, 432.3, 434.1, 435.9 and 439.5 MHz.

AST SpaceMobile are planning to launch a further 243 satellites also using 430-440 MHz for TT&C.  AST SpaceMobile say each UHF TT&C beam will support one command channel and one telemetry channel and the channel bandwidth will be between 64 kHz and 256 kHz.

In February they submitted a request to the FCC Space Bureau for use of the amateur band worldwide
https://apps.fcc.gov/els/GetAtt.html?id=371448&x=.
Also see their June 20 filing https://www.fcc.gov/ecfs/document/106201991509823/1

The 430-440 MHz band is used for a variety of Amateur Radio applications, examples include amateur space communications, weak-signal SSB, digital television, data communications, repeaters and other applications. The proposed 243 satellite constellation will cause interference to amateurs world-wide.

Read the detailed comment submitted to the FCC by the RSGB
https://fcc.gov/ecfs/document/10721151315294/1

The FCC wants to know what you think of this proposal, you can submit an Express Comment to the FCC by July 21 at
https://www.fcc.gov/ecfs/filings/express?proceeding[name]=25-201

If preferred you can submit a more detailed Standard Comment with .doc, .txt or .pdf attachments at https://www.fcc.gov/ecfs/filings/standard
Enter 25-201 into Proceeding(s) field and click on the pop-up which says ’25-201 SPACE BUREAU ACCEPTS FOR FILING AST & SCIENCE, LLC MODIFICATION APPLICATION’ fill in required fields and attach your comments file.

AST SpaceMobile say they have ground stations in Australia, Argentina, Bulgaria and Korea.

In April the FCC responded with these questions to AST
https://forum.amsat-dl.org/cms/index.php?file-download/7502/

AST replied in May to the FCC questions regarding their filing, see their answer regarding IARU
https://apps.fcc.gov/els/GetAtt.html?id=376295

Table 1 – Frequencies Reflecting the Global Capabilities of the SpaceMobile System

Table 1 – Frequencies Reflecting the Global Capabilities of the SpaceMobile System

June 20 AST Filing
https://www.fcc.gov/ecfs/document/106201991509823/1

June 20 FCC issued this Public Notice SB 25-201 – comments on the proposed use of these frequencies should be submitted to FCC by July 21, see
https://www.fcc.gov/document/space-bureau-accepts-filing-ast-science-llc-application

A summary of ~80 of the Standard Filings on FCC Proceeding 25-201 AST & Science LLC (AST SpaceMobile) has been published by Docket Rocket
https://docketrocket.substack.com/p/comments-on-asts-tt-and-c-application

Including those that just missed the filing deadline a total of 2332 comments were submitted. You view them at
https://www.fcc.gov/ecfs/search/search-filings/results?q=(proceedings.name:(%2225-201%22))

For some background on FCC attitudes see the interview the Chief of the FCC’s Space Bureau, Jay Schwarz, gave to the American Enterprise Institute (AEI). It primarily concerns the ITU-R EPFD limits but it reflects the new thinking at the FCC about getting rid of “outdated assumptions about system design and spectrum use”

How the FCC Space Bureau is Rethinking the Rules of Space
https://www.aei.org/technology-and-innovation/how-the-fcc-space-bureau-is-rethinking-the-rules-of-space/

PCMag story July 18: Ham Radio Users Clash With Starlink Rival AST SpaceMobile Over Spectrum Use by Michael Kan KB6IRQ (@Michael_Kan on X)
https://www.pcmag.com/news/ham-radio-users-clash-with-starlink-rival-ast-spacemobile-over-spectrum

PCMag story August 6: No Interference? AST SpaceMobile Defends Use of Ham Radio Spectrum by Michael Kan KB6IRQ (@Michael_Kan on X)
https://www.pcmag.com/news/no-interference-ast-spacemobile-defends-use-of-ham-radio-spectrum

PCMag story August 8: Ham Radio Users Explain Why They’re Worried About AST SpaceMobile’s Satellite Plans by Michael Kan KB6IRQ (@Michael_Kan on X)
https://uk.pcmag.com/wireless-carriers/159498/ham-radio-users-explain-why-theyre-worried-about-ast-spacemobiles-satellite-plans

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Video: A guide to using satellites in amateur radio

The online talk ‘Guide to using satellites in amateur radio’ given by Tim GW4VXE, on May 21, 2025, is now available to watch in the Pennine Ham channel on YouTube

AMSAT-UK Space Colloquium 2024

Kents Hill Park Conference Centre Milton Keynes MK7 6BZAMSAT-UK is pleased to announce that the 2024 Colloquium will take place alongside the RSGB Convention at Kents Hill Park Conference Centre, Milton Keynes, MK7 6BZ on the weekend of 12/13th October 2024.

As in previous years, the AMSAT-UK Colloquium will run as a separate stream within the RSGB Convention and will include presentations on a variety of satellite and space related topics.

The Annual General Meeting of AMSAT-UK will take place during the colloquium.

An AMSAT Gala Dinner will be held on the evening of Saturday 12th October at the Marriott Delta Hotel on Trimbold Drive, Kents Hill, Milton Keynes MK7 6HL. Attendance is restricted this year at the hotel and a limited number of tickets are on sale via the AMSAT-UK Online Shop https://shop.amsat-uk.org/

The cost of the Gala Dinner is £39 per person and includes a three course meal with tea / coffee at its conclusion.

Alongside the Gala Dinner, AMSAT-UK has negotiated a deal at the Marriott Delta for the evening of Saturday 12th October 2024. These rooms include breakfast on Sunday 13th and are priced at £89 per room for single occupancy. Tickets for the Gala Dinner can be purchased on the AMSAT-UK Online Shop.

Bookings for the Gala Dinner are now available on the AMSAT-UK Shop, but must close on 1st October 2024 unless sold out sooner, so please book early to avoid disappointment.

Entrance to the RSGB Convention is managed by the RSGB and you will be required to purchase Day Tickets for the Saturday and/or Sunday to attend the AMSAT-UK Colloquium.

RSGB Convention booking is at https://rsgb.org/main/rsgb-2024-convention/

The schedule of Colloquium talks will be released closer to the date.

July OSCAR News now available

2024-07 Oscar News Front CoverE-members of AMSAT-UK can now download the July 2024 edition of OSCAR News, issue 244, here.

The paper edition edition will be sent to postal members and should arrive in the next 2-3 weeks.

In this issue:
• From the Secretary’s Keyboard
• Satellite News
• ARISS International Face to Face Meeting 2024 and 40th Celebration of Amateur Radio on Human Spaceflight by Ciaran Morgan, M0XTD
• QO-100 School contacts by John M5JFS
• FUNcube+ AMSAT-UK’s Next Mission by David Bowman, G0MRF
• Assessing Path Loss Due to Weather in Newfoundland by David Bowman, G0MRF
• VO1/M0XUU Operation from Newfoundland by R. Gopan M0XUU
• The QO-100 Challenge from VO1 by Graham, G3VZV
• VO1NAR Beacon by Graham Dillabough, VO1DZ

In ON245 we will continue with articles on the QO-100 Challenge from the VO100QO

AMSAT-UK FUNcube Mission Patch

AMSAT-UK FUNcube Mission Patch

Membership of AMSAT-UK is open to anyone who has an interest in amateur radio satellites or space activities, including the International Space Station (ISS).

E-members of AMSAT-UK are able to download the quarterly publication OSCAR News as a convenient PDF that can be read on laptops, tablets or smartphones anytime, anyplace, anywhere. Join as an E-member at Electronic (PDF) E-membership

PDF sample copy of “Oscar News” here.

Join AMSAT-UK using PayPal, Debit or Credit card at
http://shop.amsat-uk.org/

E-members can download their copies of OSCAR News here.

Newfoundland QO-100 Contact Successful – More Planned

First Newfoundland contact via QO-100 between VO1/M0XUU and G0MRF

First Newfoundland contact via QO-100 between VO1/M0XUU and G0MRF

On Saturday, May 11, 2024, Gopan VO1/M0XUU (VU3HPF) succeeded in making the first contact from North America through the amateur radio QO-100 geostationary satellite transponder located at 26° East.

Gopan's Screenshot of First Newfoundland QO-100 Contact

Gopan’s screenshot of first Newfoundland QO-100 contact

Gopan was in Newfoundland which is just outside the coverage area of QO-100, the elevation at Signal Hill at St. Johns is below the horizon at -0.9°.

He used FT-8 to have a trans-atlantic contact with David G0MRF in south-west London. David reported it was tough going with a lot of QSB.

Gopan will be in Newfoundland until May 15.

In a post on X Gopan reported his signal into QO-100 was not strong enough to permit SSB operation.

Dish used by VO1/M0XUU in Newfoundland

Dish used by VO1/M0XUU in Newfoundland

The transmit equipment Gopan used comprised, ICOM IC-705 with 2.4 GHz Up-converter from DX Patrol, feeding a homemade 2.4 GHz amplifier delivering 10 watts output to a Helix 2.5 turn YATT design.

The receive side comprised a homemade 10 GHz Down-converter was based on a design by David G0MRF, a modified LNB all controlled by a Leo Bodnar M0XER GPSDO.

The dish was an 80 cm offset.

The software used was SDR Console and Airspy for setting up the station and MSHV in standard mode for FT8/FT4.

After his initial contact with David G0MRF, Gopan went on the work several other stations including Sadan TA4SO in Turkey.

David G0MRF will be joining Graham G3VZV on a QO-100 Dxpedition to Newfoundland from May 15-19.

They are taking enough equipment to enable transmissions on QO-100 using SSB / CW / FT8 / FT4 / Digital Amateur Television (DATV).

Graham G3VZW testing QO-100 equipment before Newfoundland Dxpedition with David G0MRF

Graham G3VZW testing QO-100 equipment before Newfoundland Dxpedition with David G0MRF

A video of the presentation ‘Making QO-100 contacts from North America – A new challenge’, given by Graham G3VZV at the 2022 AMSAT-UK Colloquium can be seen at
https://amsat-uk.org/2022/11/01/making-qo-100-contacts-from-north-america-a-new-challenge/

AMSAT-UK issue a special Certificate of Achievement for QO-100 contacts made from North America.  Applications should be sent to awards@amsat-uk.org

Full details of the award in this Word Document

QO-100 North America CertfificateYou can follow posts on X at:

Gopan M0XUU – https://X.com/vu3hpf
David G0MRF – https://X.com/g0mrf
Graham G3VZV – https://X.com/G3VZV

Stefan VE4SW reports he will be traveling to Newfoundland and will be using the callsign VO100QO on QO-100 from May 13-17, he writes:

“VO100QO a special callsign for the activation of QO-100 from St John’s in Newfoundland will be used by the “Amateur Radio Satellites and Systems – Canada” Association starting Monday, May 13, at Signal Hill or another suitable location (weather permitting). Canadian amateur radio operators Stefan Wagener VE4SW and John Langille VE1CWJ will use a 1.8m dish and up to 100W on SSB to reach QO-100 at -1 degree elevation.

We invite all stations and operators in or near St John’s to join us in person and be part of the story. We will operate from Monday, May 13th to Friday, May 17th (weather permitting). Contact VE4SW (email on my QRZ page) for local information and timing.

The “Amateur Radio Satellites and Systems—Canada” Association will issue special certificates for successful contacts, and all QSOs will be logged into LoTW. Please see our “VO100QO” QRZ page for updates starting Sunday, May 12.

We would very much like to acknowledge the support of “DX Patrol” in Portugal (https://dxpatrol.pt) and António Matias for his support. We will use the DX Patrol QO-100 Groundstation V2 and other equipment for our attempt!”

Follow Stefan VE4SW on X – https://X.com/StefanWagener3

Information on QO-100 is at https://forum.amsat-dl.org/index.php?board/3-qo-100-es-hail-2-p4-a/

FT-8 QO-100 contact between Gopan VO1/M0XUU and TA4SO

FT-8 QO-100 contact between Gopan VO1/M0XUU and TA4SO