[amsat-bb] EO-79 transponder activation

Mike Seguin n1jez at burlingtontelecom.net
Mon Dec 21 14:06:34 UTC 2015

I just got on EO-79 here. ~ 08:55 EST. I found my downlink after setting 
my uplink +12 kHz from published spec.

Downlink seemed OK - maybe a bit weak. Significant fading. This was a 
fairly low pass for me.

Unfortunately, nobody else on the transponder.


On 12/21/2015 5:16 AM, Wouter Weggelaar wrote:
> Hi All,
> Today, 21st of December 2015 at 1038 UTC, it is planned that the EO-79
> transponder will be turned on for a prolonged period.
> The FUNcube transponder subsystem on QB50p1 (EO-79) had been provided by
> AMSAT-UK and AMSAT-NL and is a similar subsystem as on FUNcube-1, but
> without the telemetry downlink circuitry.
> The current software running on EO-79 does experience occasional reboots.
> When these reboots happen, the transponder is automatically turned off and
> will have to be turned back on by a command station. The FUNcube team has
> selected a few command stations to do so, but be advised the transponder
> may be off.
> TLEs:
> AMSAT keps name: EO-79
> Celestrak keps Name: QB50P1
> Celestrak file: cubesat.txt
> NORAD #    40025
> COSPAR designator    2014-033-R
> Frequencies:
> *Uplink:* 435.035-435.065 MHz LSB
> *Downlink:* 145.935-145.965 MHz USB
> EO-79 has been set to only beacon the normal AX.25 beacon every 30 seconds
> instead of 10 seconds. The beacon frequency is 145.815MHz and consists of
> AX.25 frames on BPSK. more details about the downlink can be found on the
> ISIS HAM page at http://isispace.nl/HAM/qb50p.html
> We kindly request you to share your experiences with the BB so everyone can
> benefit from operating tips and tricks, as well as being up-to-date on the
> status.
> We would also welcome any observation related to the transponder behaviour
> when the AX.25 beacon comes on.
> Just like FUNcube-1, the crystal oscillator circuits exhibit drift with
> temperature. This means manual tuning will probably work best.
> Lastly, the commanding team will not be available over Christmas, so the
> current activations are planned from today until Thursday 24th and from
> Monday 28th until Thursday 31st
> 73 and have FUN
> Happy Holidays
> Wouter Weggelaar, PA3WEG
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Mike, N1JEZ
"A closed mouth gathers no feet"

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