[amsat-bb] EO-79 transponder activation

Rick Kowalewski rick at vk6xlr.net
Mon Dec 28 14:56:27 UTC 2015

Hi All

EO-79 Pass over VK, 28 Dec 1428-1441UTC
Transponder was active.  Good signals on the downlink.

Uplink offset:
Start of pass: +23.5khz
End of pass: +28.5kHz


On 28/12/2015 17:09, Wouter Weggelaar wrote:
> Hi All,
> Just as a reminder, we will start our second activation today, Monday 28th
> until Thursday 31st.
> The first activation has shown us that the uplink frequency seems to be off
> by +12kHz, so please adjust your uplink frequencies accordingly. We are
> also seeing that activating the transponder makes the satellite power
> negative, meaning the solar arrays can not generate enough power to keep
> the transponder running permanently. This is not unexpected as the
> satellite is operating in a different mode than originally anticipated
> during the design phase.
> We are discussing various ways to solve this, including multiple ways of
> scheduling the transponder operations. With these discussions ongoing we
> would still like to try the second activation and obtain some more data
> about the system. We will activate the transponder for as much time as the
> power budget allows, but please be aware that you may find the transponder
> to be off while the batteries recharge.
> 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
>> * + 12KhzDownlink:* 145.935-145.965 MHz USB
>> 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.
>> 73 and have FUN
>> Wouter Weggelaar, PA3WEG

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