[amsat-bb] EO-79 transponder activation

Wouter Weggelaar wouterweg at gmail.com
Mon Dec 21 10:16:58 UTC 2015

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.

AMSAT keps name: EO-79
Celestrak keps Name: QB50P1
Celestrak file: cubesat.txt
NORAD #    40025
COSPAR designator    2014-033-R

*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
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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