Author: SM0TGU

Hej

Dagens nät på 3740 Khz klockan
10.00

Deltagare
SM0AIG
SM4EFW
SM4JLX
SM6NZV
SM7WSJ

Svåra
konditioner,,,

*ISS synbar i sommarnatten

HO-68
12:45…Turn
On–FM/PACSAT
Europe,NA,South America
13:30…Turn Off

16:00…Turn
On–CW/SSB
India,West Asia,Africa,Europe,NA
16:45…Turn
Off

17:50…Turn On–CW/SSB
India,West
Asia,Africa,Europe,NA
18:35…Turn Off

*SO-67 tillbaka

After
much delay we are now in a position to re-activate the SA-AMSAT

payload schedules on a regular basis again!

During the downtime we
conducted several experiments in order to investigate possible alternatives
for the “cut-off” problem experienced by many at the end of last year /
beginning of this year. The cut-off is caused by SW running on piggyback
electronics that continues to gate the received audio onto the transmitter
for about 3s after a specific ground transmission has ended, whereafter the
received audio is cut off. The SW then waits for the next ground transmission
with a valid “transponder” tone embedded, before gating the audio onto the
transmitter again. So if a second transmission starts within the 3s “tail”
period, it will be cut off when the 3s expires.
Listen to this mp3 recording
as an example: http://tinyurl.com/38vvg3o

Unfortunately
the piggyback electronics does not have reprogramming
functionality, so we
are not able to change the SW. We did however manage to implement a
mechanism on the satellite transponder (used by the piggyback) that should be
of some assistance when using the payload: the PTT of the transmitter now
STAYS ON for the duration of the payload activation (i.e. 15 min), regardless
of a valid “transponder” tone received. Note that this does not get rid
of the “cut-off” problem, nor of the requirement to embed a valid tone
when you want to use the payload – see detailed explanation below.

The
following example depicts the ideal usage scenario of the payload:

1. As
the satellite comes over the horizon, an unmodulated carrier
(“quieting”)
will be received by all on UHF

2. Person A starts to transmit on VHF
(with valid “transponding” tone
embedded in the transmission) and the
transmission is relayed on UHF

3. When Person A releases his/her PTT, the
satellite will continue to
transmit what it is receiving (usually this will
be “noise”) for a further
?3s. Nobody should start to transmit during this
time!

4. At the end of the ?3s period, everybody will again hear
the
unmodulated carrier.

5. NB: only when this unmodulated carrier is
heard should Person B
start to transmit. Listen to this mp3 recording as an
example of valid
usage: http://tinyurl.com/32rjbxm

I
suppose this will take some getting use to – at least the system has
a built-in “punishment” mechanism for the impatient! 😉

Please refer
to previous posts on general voice quality optimization when using the
SA-AMSAT payload on SO-67.

I will request Gladys Magagula at the
Satellite Application Centre to
obtain regular schedules from the
regional coordinators as soon as possible. We will start off with day passes
only, transmit on 2.5W and see how things go.

En fortsatt god sommar
tillönskas!
73 Håkan SM7WSJ

Hej,

Dagens nät på 3740 Khz klockan
10.00

Deltagare
SM6NZV
SM7FWZ
SM7WSJ

*Atlantis
nere på jorden igen

*UNITEC-1
http://www.arrl.org/news/amateur-community-needed-to-assist-japanese-amateur-interplanetary-satellite

*Ovanligt
problem med Geostationär satellit (titta på videon i länken)
http://news.bbc.co.uk/2/hi/science_and_environment/10150614.stm

*X-51A
Waverider (inte direkt satellitrelaterat men fort går det,,)
http://news.yahoo.com/s/ap/20100527/ap_on_bi_ge/us_hypersonic_flight_2

*P3E
P5A (Kommit lite info från våra grannar i öst)

Hi all
Microwavers,

AMSAT-OH is working on the S/X band
coherent/linear
transponder for P3E. The Coherent mode is a
fully
functional testbed for the P5A ranging transponder.

Especially
the linear transponder prototype has been
assembled and verified with
over-the-air tests and
laboratory tests. Flight versions of the
submodules
have been and are being produced at this time with
our eyes now
set on integrating these together and
cabling the whole job
together.

Full verification of the Coherent Mode requires a
fully
functional command station AND a functional
IHU + CAN environment to
interface our data ports with.
No such tests have been available yet, but all
our
preliminary testing and evaluation of the Coherent
Processor have
shown proper operation of the design
and circuitry (e.g. locking onto a
“modulated” uplink
carrier, tracking this etc.). So far correct
live
operation of the Coherent Mode is our biggest questionmark.

Our
national team meets on a regular basis every 4 – 6 weeks
for testing and
followups of the work of each individual.

This transponder is especially
complex as you can
see from these key figures:

* 9 different local
oscillators
* All local oscillators locked to the common 10 MHz USO
* 21
different frequency mixers
* 13 different intermediate frequencies
*
Linear Mode output power on 10 GHz: 3 W PEP
* P5A Mode output power on 10
GHz: 1 mW PEP
* 38 control lines on the CAN interfaces
* 2 CAN interfaces,
one in multiplexed mode
* 4 dedicated direct control lines interfacing with
the IHU
* 14 analogue telemetry lines to the CAN bus
* Coherent Mode
Uplink/Downlink ratio is fixed at 30:7

Here you may find a general
outline webpage, though unfortunately in
Finnish for the benefit of our OH
supporters, but you might still enjoy
the photos and drawings:

http://www.rats.fi/rats/amsat-oh/

Our
team sincerely hopes funding will eventually be found
for P3E/P5A – this is
the only thing that keeps us motivated
to continue our work. On the other
hand we are clearly behind
schedule, so the delays are welcome 🙂 But then
again, any
news of progress would boost our production rate phenomenally
😉

73 Michael, OH2AUE

Ha en god vecka! 73 de Håkan SM7WSJ

Hej,

Dagens nät på 3740 Khz klockan
10.00

Deltagare
SM4EFW
SM4JLX
SM5HL
SM6NZV
SM7FWZ
SM7WSJ

En
del av punkterna

*Rymdfärjan lämnar ISS

*Unitec-1 på väg till
Venus

http://www.southgatearc.org/news/may2010/unitec1_signal_received.htm

*Prisma
ett svenskt satellitprojekt

http://www.prismasatellites.se/?sid=8893

*AO-51
ska inte användas i eclipse

*Dom analoga satelliterna fungerar för övrigt
bra.

73 de Håkan SM7WSJ

Hej,

Dagens nät på 3740 Khz klockan
10.00

Deltagare
SM4JLX
SM6NZV
SM7FWZ
SM7WSJ

*Kiwisat

Hans
Holtz ZL1HB and Andrew Cammell ZL1AVC explains the design and operation of
the KiwiSAT central power con-trol system
know as the Battery Control
Regulator or BCR. Watch at:
http://tinyurl.com/28ocp8h

*FO-29

Strömförsörjningen
verkar börja tappa i effektivitet
http://www.ne.jp/asahi/hamradio/je9pel/fo29sola.htm

*VO-52
fyller 5 år och Amsat india ser framåt.

Amsat India has 2 linear
tranponders ready and we Amsat India are asking ISRO for a higher orbit to
cover a larger foot print and longer pass duration.Its no use having another
LEO as HAMSAT 1 .Hamsat 1 will be celebrating its 5th birthday on 5 May and
ISTRAC has been
monitoring its health and its utilisation, they report that
Hamsat 1 is in
good health and should serve the hams for many more
years.
In this regard there was an email by VU2WMY Mani a few days ago asking
for USER feedback like utilisation & experiences by hams all over the
world with Hamsat 1. Please send in your reports , utilisation and
experiences with Hamsat by email and the same will be forwarded to
ISRO.

Best regards Pop VU2POP Dir Technical Amsat India

*Ny
satellitantenn (numera är det symaskin som gäller vid antennbygge)

http://blog.makezine.com/archive/2010/05/collapsible_fabric_yagi_antenna.html

73
Håkan SM7WSJ