EO-79 transponder activation

EO-79 and EO-80 - Image Credit ISIS

EO-79 and EO-80 – Image Credit ISIS

On December 21, 2015 at 1038 UT, the EO-79 transponder was 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 [See note below]
*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 145.815 MHz and consists of AX.25 frames on BPSK. More details about the downlink can be found on the ISIS Ham Radio page at http://isispace.nl/HAM/qb50p.html

We kindly request you to share your experiences with the AMSAT Bulletin Board 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

Mike Seguin N1JEZ notes:  I found my downlink after setting my uplink +12 kHz from published spec

SatPC32 tracking software Doppler SQF information used by Peter VK4NBL:

Graham Shirville G3VZV says that due to platform sharing considerations the FUNcube transponder on EO-79 uses 1/4 wave monopole antennas rather than the full dipoles used on AO-73. The actual effects of this difference in practice may be interesting to observe.

AMSAT Bulletin Board (AMSAT-BB) http://www.amsat.org/mailman/listinfo/amsat-bb

Satellite Tracking https://amsat-uk.org/beginners/satellite-tracking/