I've sent an email to the point of contact on the IARU web page for TTU100 and will relay any info if I receive a reply. If the X-band transmitter is on over this part of the planet I'll be using a 68 x 61 cm offset feed dish and initially just let the satellite fly through the beam. If I see a decent signal I'll get serious about trying to track it.
I'm using an AirSpy connected to the LNB output. If I capture a I/Q recording I'll post a link for anyone interested. 73, Ken, W7KKE
-----Original Message----- From: AMSAT-BB amsat-bb-bounces@amsat.org On Behalf Of Daniel Estévez via AMSAT-BB Sent: Monday, June 15, 2020 13:38 To: amsat-bb@amsat.org Subject: Re: [amsat-bb] Estonia's TTU100 X band satellite questions
Hi Graham and Ken,
I'm also looking at this satellite with interest. Maybe I'm too optimistic, but I'm thinking that hand aiming a 60cm dish might work (at least to receive some signal). Maybe we could even convince the operators to run some tests for us outside of Estonia.
I don't want to overwhelm the operators with several emails asking the same questions, so if you get in touch with them, please share your findings.
According to the IARU coordination sheet, the modulation will be OQPSK with rates between 62.5kbps and 20Mbps. For the higher rates, a decent high bandwidth SDR is needed. The lowest rate is easiest to copy, and still provides a decent challenge in my opinion, so something to consider if we ask for some specific tests for interested Amateurs.
I could build a decoder for the modulation if we get some documentation or if it looks like something standard (maybe it uses CCSDS?). So if you catch a recording, please do share.
Best,
Dani EA4GPZ.
El 15/6/20 a las 18:29, Graham Shirville via AMSAT-BB escribió:
Hi Ken,
The IARU website has this info http://www.amsatuk.me.uk/iaru/finished_detail.php?serialnum=565 maybe you can contact the operator to find out the likely operating schedule.
Tracking the doppler will be fun and also keeping the dish within the required 1- 2 degree pointing accuracy is also likely to be a challenge. However it appears that there may be a number of other 10GHz downlinks being planned for low earth orbit so all experience will be extremely valuable.
73
Graham G3VZV
On 15/06/2020 17:15, Ken Swaggart W7KKE via AMSAT-BB wrote:
In a tweet from AMSAT-UK I saw that an Estonian university will launch their TTU100 cubesat on Friday with a X-band downlink on 10465 MHz. Thought it would be an interesting challenge to aim my X-band dish with a sat TV LNB at closest point of approach and see if I can see anything on the SDR waterfall. My LNB output would be at 715 MHz and the Doppler at AOS would be approximately +533 KHz!
A couple of questions before I start configuring the equipment:
- Will the 10465 MHz downlink be on during North America passes or
only when in range of the Estonian ground station?
- What is the modulation? It's an imaging satellite so I expect it
will be high data rate.
73,
Ken, W7KKE
Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb