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CX2SA > SATDIG 05.08.11 21:06l 145 Lines 4929 Bytes #999 (0) @ WW
BID : AMSATBB6433
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Subj: AMSAT-BB-digest V6 433
Path: IZ3LSV<IK6ZDE<VE3UIL<VE9MPF<CX2SA
Sent: 110805/1904Z @:CX2SA.LAV.URY.SA #:20287 [Minas] FBB7.00e $:AMSATBB6433
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. More on the transponder. (Rsoifer@xxx.xxxx
2. 2 X CW QSO via ArisSat-1 (Andre' v Deventer)
3. Re: ARISSat-1 over West Malaysia (Phil Karn)
4. Arissat-1 Commanding? (Burns Fisher)
5. ARRISat-1 Keps now available from Celestrak (Alan P. Biddle)
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Message: 1
Date: Fri, 5 Aug 2011 13:08:50 -0400 (EDT)
From: Rsoifer@xxx.xxx
Subject: [amsat-bb] More on the transponder.
To: amsat-bb@xxxxx.xxx
Message-ID: <24fbb.27ffe8fe.3b6d7da2@xxx.xxx>
Content-Type: text/plain; charset="US-ASCII"
Further to my last email, a full quarter-wavelength antenna for 435 MHz
would be about 6.5 inches long. Lou estimates that the actual antenna is
only about 1.5 inches. The short length has two effects: a reduced capture
area for reception, and a greater likelihood of blockage by the main body of
the spacecraft. If it's blocked, it won't hear much of anything. If it
isn't, it looks like it will hear the bigger AO-13/AO-40 class stations
(typical EIRP about 1 kW). With my EIRP of 50 watts, I tried CW instead of
SSB.
I heard myself for about 2 minutes, but was only 449. We'll see if
anyone else can hear me in the next few days.
73 Ray W2RS
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Message: 2
Date: Fri, 5 Aug 2011 19:23:10 +0200
From: "Andre' v Deventer" <vandeventeraj@xxxxxxxx.xxx>
Subject: [amsat-bb] 2 X CW QSO via ArisSat-1
To: "Amsat-Bb" <amsat-bb@xxxxx.xxx>
Message-ID: <NHEDJLNPLJCJMJDIBPGKMEHFCFAA.vandeventeraj@xxxxxxxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
a 2x way cw contact with ZS6A Pierre.
Got to be quick to beat the fades.
Got a nice recording of this contact too.\
73 andre ZS2BK
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Message: 3
Date: Fri, 05 Aug 2011 10:28:23 -0700
From: Phil Karn <karn@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: ARISSat-1 over West Malaysia
To: "Sion Chow Q. C. (9W2QC)" <9w2qc@xxxxx.xxx>
Cc: sangatsingh@xxxxx.xxxx amsat-bb@xxxxx.xxx
Message-ID: <4E3C2837.8050504@xxxxxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
On 8/4/11 8:04 PM, Sion Chow Q. C. (9W2QC) wrote:
>
> 2. Does the CW beacon needs to be really +/- 100 Hz of the yellow
> line? The reason for this is that I would like to see how much offset
> should I apply to doppler control, for possible automated reception.
Tuning the CW beacon to 500 Hz automatically centers the BPSK1000 signal
at 1500 Hz. I didn't put in a whole lot of frequency tolerance in the
BPSK-1000 demodulator because the signal is 2 kHz wide from null to null
and it would begin to be chopped off by the edges of the receiver's SSB
filter. So while you should ideally tune to +/- 100 Hz you might go to
+/- 200 or even 300 Hz and it will *probably* still work, but I wouldn't
go too much wider.
Go ahead and experiment; I'd be interested in any reports on how well my
demodulator (which is incorporated into both the Windows and Mac
telemetry programs) tolerates tuning errors. Frequency acquisition and
data synchronization are the hardest parts of any digital demodulator,
and I'd like to know where there's room for improvement.
73, Phil
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Message: 4
Date: Fri, 5 Aug 2011 14:03:56 -0400
From: Burns Fisher <burns@xxxxxx.xx>
Subject: [amsat-bb] Arissat-1 Commanding?
To: amsat-bb@xxxxx.xxx
Message-ID:
<CABX7KxVwfJXtdWWDvyDtaw6bm7hMKZ65rnLHFNjmtE-jm50yJA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
I saw on one of the NASA announcements that the snarffled 70cm antenna would
mean no commanding of the bird. (This was probably before it was realized
that that receive actually seems to work). But the question I have is
whether there IS some commanding of the bird possible. I guess you have to
be able to turn it off to satisfy the FCC (true?) but can other things be
done? I assume/home that the command channel is encrypted, so disclosing
its existance is not compromising the bird.
73, Burns W2BFJ
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Message: 5
Date: Fri, 5 Aug 2011 13:46:31 -0500
From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Subject: [amsat-bb] ARRISat-1 Keps now available from Celestrak
To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>, "SAREX-BB" <SAREX@xxxxx.xxx>
Message-ID: <2AE0AA909B9144689C1B0B9CB1D953A4@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
Just checked the latest AMATEUR.TXT download from Celestrak, used by many
tracking programs. ARRISat-1 is now included, though with the alternate
name RADIOSCAF-B. Thanks as always to Tim Kelso.
Alan
WA4SCA
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End of AMSAT-BB Digest, Vol 6, Issue 433
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