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Re: Cubesat's



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Hi,

Thank you very much for listening for us (and thank you to Aalborg for
listening for you :-)

Unfortunately, we are certain that you have heard our ground station. We do
not know your exact location, but you are Danish? Using an omni-directional
antenna, you will have much better chances We transmit exactly that sequence
when we are polling the satellite to try to coax it into answering. We are
using directional antennas, but have so far not succeeded in getting any
answers. We are currently transmitting a command for the satellite to repeat
the antenna deployment in case it can hear us, but have had problems during
the deployment. The satellite is able to receive, although with less
performance, with its antenna folded.

Due to the uncertain orbital elements on the Cubesats, we are tracking the
first known element until the top of its pass, then we stop the antenna
motion. In this way, the antenna beam will stay while the satellites will
enter the focus at zero doppler shift, enabling us to sweep the orbital
plane.

- 10 minutes later -

No immediate results came from this experiment. We have not received any
replies from DTUsat. However, if the antenna is "more deployed" now, the
signal strength from the satellite will increase considerably. Also, we
still hope for better orbital elements. The transmitter onboard Quakesat is
5-6 dB stronger, but they have reported up to 18 dB S-meter readings. We get
nothing, Aalborg gets 2-3 dB increases in total signal strength above the
noise floor. We should do better than that.

The search using radios is difficult because of the low duty cycle of the
beacons, so we are primarily waiting for NORAD :-)

73,

        /Niels Holmgård Andersen
        DTUsat team



> > Hi,
> > Yesterday at around 15:36 UTC I heard distinct bursts on freq. around
> > 437.479 MHz, 5 seconds interval, and lasting approx. half a second.
> >
> > Today this occurred again, at 15:18 UTC. at freq. around 437.471 MHz.
> >
> > The only cubesat I know of at this freq. is DTU-sat, but they should be
> > transmitting with 2 min. intervals....
> >
> > I was listening in SSB, sounded like two tones... I can not give az or
> > elev. since I am using omni-dir. at this stage.
> >
> > Any ideas ???
> >
> > 73 de OZ4UI / Lars
> >
> >
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >

----
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