[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

RE: Re: PICPOT Power!



Hi David,

I did notice it on a recent review of the IARU site but thought nothing of
it since there wasn't ever anything discussed about it. The March 06 launch
date didn't peak my curiosity since those launch dates are rarely accurate.

What surprises me is that so many satellite builders are working under the
"radar screen" and seem to be avoiding detection. So now we will have a 2440
MHZ signal (in our amateur band) and I would guess so few will have the
ability to do anything about it (downconverter and demodulation issues), at
least in the near term.

I would agree with your analysis of the solar cells and power budget. A
simultaneous 1 watt signal at U and S seems unrealistic unless, as you point
out, it's activated over Italy.

Douglas, KA2UPW/5, raises a good point in his post. I'm not sure what the S
band signal will sound like.

I hope he gets an answer!

Regards...Bill - N6GHz

-----Original Message-----
From: owner-AMSAT-BB@amsat.org [mailto:owner-AMSAT-BB@amsat.org]On
Behalf Of G0MRF@aol.com
Sent: Sunday, July 23, 2006 12:45 AM
To: bill@hsmicrowave.com; amsat-bb@amsat.org
Subject: [amsat-bb] Re: PICPOT Power!


Hello Bill.

Looks like we all missed that satellite although it is detailed on the  IARU
list showing an original launch date of March 2006.


    Supporting Organisation  Politecnico di Torino   Contact Person
dante.delcorso@polito.it.no.spam  Headline Details: A  picosat scheduled for
an March
2006 DNEPR launch into a 700km 98 deg  inclination orbit. Intends to take
pictures and communicate on UHF and S  band at 9k6 AX25 using "FSK and GFSK
modulation.The coordinated  frequenices are UHF:437,445 MHz and S Band
2440.00 MHz
 Applications Date:  11/03/2005  Freq coordination completed on 28/12/2005


It's really nice to see those hi res pictures on the site but looking at
the
solar cells its highly unlikely that it could produce anywhere near 1W
output unless it runs a negative power budget and is only switched on over
Italy.
It looks like it has 2 cells per side with none on the axis that holds the
camera and helix. If the cells are similar to the Tecstar ones then it's
possible to roughly estimate the power budget.  The Tecstar cells are
characterised with a load of 337mA and typically produce between 1.6 and
2.54V.  If we
take 2.0 as a working value, then we get 1350mW per side.
If there are 2 sides illuminated then it has 2.7W (ish) of DC input.

For a 'cubesat' it looks really robust!  But I hope they've put enough
Kapton on it. - There is a lot of exposed aluminium remaining which will get
very
hot.

Fingers crossed.  - Time to dust off my 'Arsene'  2450 down  converter.

Regards

David   G0MRF


In a message dated 23/07/2006 00:50:11 GMT Standard Time,
bill@hsmicrowave.com writes:

It does  appear after reading the info on their web site that the U and S
band  downlinks will be running 1 watt output. The 437.485 MHz signal goes
to
a  helix which would appear to have decent gain so I'm not sure if they  are
taking about 1 watt ERP or 1 watt into the antenna.

The S band  output goes to what amounts to a patch antenna, also with some
gain. So  same question there.

In any event, the satellite should offer a "large"  U and S band signal
(albiet 9600 baud noise) to monitor.

Good luck  to all on this upcoming launch. We'll have a bunch of new signals
to track  and monitor.

Regards...Bill - N6GHz
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
----
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home