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More PicPot Details



For those of you interested in the PicPot satellite, Claudio Sansoe -
IW1EZN, was kind enough to answer some questions about the PicPot satellite
to be launched this Wednesday, 7/26. Note that it is not part of the Cal
Poly CubeSat P-POD launch regime but another stand alone satellite going on
the same ride.

Claudio's responses are in bold italics (assuming the formating comes
through on your end)


Bill Ress wrote:

Thanks for the prompt reply Claudio,

Just a few more question, so please be patient with me.

It looks like the U antenna, a helix, will have some gain so is it 1 watt to
the antenna or 1 watt effective radiate power (ERP)? Same question for the S
band signal, whose antenna appears to be similar to a patch. Is the U
antenna RHCP or LHCP? What is the polarization of the S band antenna?
  
The power is to the antenna. The antennas have some gain, but I was not
involved in the design of the antennas. I will turn your question to our
antenna men, so I will avoid to tell you nonsense (although I have some
ideas...). I will answer tomorrow, as it is now 7pm in Italy. Take into
account that we only have a passive control on the orientation of the
satellite, which will not always be pointing towards Earth, so I prefer not
to take into account the antenna gain in the link budget.

During the .3 sec period, is the modulation on U a 9600 baud burst or CW. On
S band is it a 10Kbit burst or CW.
  
It is a burst on both frequencies. As I said, it is a standard APRS packet
on U which should be understandable by a TNC. We tried it with a DSP2232
using modem 18 and with a timewave PK96. We found some problems in some
cases and we think there is a frequency drift in our frequency synthetizer
(apart from doppler of course)

Thanks for the clarifications and can I relay this information to the
AMSAT-NA bb?
  
Sure

Regards and 73's...Bill - N6GHz
  
Best regards! Claudio - IW1EZN

-----Original Message-----
From: Claudio Sansoe [mailto:claudio.sansoe@polito.it]
Sent: Monday, July 24, 2006 9:20 AM
To: Bill Ress
Subject: Re: Re PICPOT


PicPot does not have a GPS and we did not provide firmware to let it
know where it is, so it will be always using 1W, but in the rest of the
world its activity will be limited to 0.3s every minute on both
frequencies (for what we call standard telemetry and can be seen as a
beacon). When PicPot will be above Italy we will send commands such as
"take a picture" or "download it", or "move the inertial wheel of a
certain amount" and PicPot will aknowledge the command (we hope...) and
send data. In a future, if the satellite performs nominally, we hope to
be able to publish the command set or a part of it so that it will be
possible to use PicPot from other parts of the World.
Best 73's
Claudio IW1EZN

Bill Ress wrote:

  
Hi Claudio,

Best of luck and good wishes on your upcoming launch of PicPot.

Several of us are curiuos to know if you will indeed be transmitting 1 watt
(30 dBm) on U ans S as indicated in your online documents or if that power
will be used just over Italy.

Best regards and 73's...Bill - N6GHz (California)

[demime 1.01d removed an attachment of type application/ms-tnef which had a name of winmail.dat]
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