[amsat-bb] A0-73

[Colin Hurst]

Some personal thoughts on this subject.
On the 14th December AO-73 was placed back in Transponder mode after having
been in Educational Mode for many months to examine the performance of AO-73
in full sun. AO-73 is currently experiencing its second full sun encounter
which will last until April 2019.
The first experience was earlier this year when a number of observations
were noted in AO-73's attitude. A controlled experiment has been undertaken
during the first stage of this current full sun encounter to understand and
quantify those previous observations.

Simply put, while in full sun AO-73 slowly speeds up due to Propeller Effect
and reaches a point where due to an offset Centre of Gravity the Nutation
becomes excessive and AO-73 finally ceases to rotate about its Z-Z axis.


Points of clarification.
Educational Mode 300 milli-watts Beacon downlink.
Transponder Mode 30 milli-watt Beacon.
Propeller Effect occurs from the Materials Experiment on AO-73. Schools STEM
Initiative.
https://funcube.org.uk/education-outreach/
The fading you are currently seeing is medium to high Nutation (Wobble about
the Z-Z axis).
AO-73 has not ceased to rotate about the Z-Z axis or start tumbling.
For past history please refer to Mike's Blog and in particular.
http://www.dk3wn.info/p/?cat=79

73 Colin VK5HI

-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Jean Marc
Momple
Sent: Tuesday, 18 December 2018 04:15
To: Hasan al-Basri
Cc: amsat-bb at amsat.org; corvanheiningen at outlook.com
Subject: Re: [amsat-bb] A0-73

Dear All,

Also noticed quite a difference on AO-73 reception this side, it used to be
100% reliable but less decodes theses day, I have not investigate same but
for sure there is a degradation somehow.

Just FYI

73


Jean Marc (3B8DU)

> On Dec 17, 2018, at 8:35 PM, Hasan al-Basri <hbasri.schiers6 at gmail.com>
wrote:
> 
> Agreed, severe QSB even with RHC rx antenna.
> Also, I'm not rx anywhere near the number of TLM frames since the xponder
> was turned on.
> 
> 
> Hasan
> 
> 
> On Mon, Dec 17, 2018 at 7:19 AM Cor van Heiningen <
> corvanheiningen at outlook.com> wrote:
> 
>> Have the last days qso s made via AO-73 sat the rx goes from s 9 to 0
>> sometimes with a lot of QRM.
>> I think the sat turned around its axis faster than a few months ago.
>> Many stations have problems with QSO S via this sat.
>> 73
>> PE1NIL