| |
CX2SA > SATDIG 12.04.11 13:30l 1187 Lines 40055 Bytes #999 (0) @ WW
BID : AMSATBB6208
Read: GUEST
Subj: AMSAT-BB-digest V6 208
Path: IZ3LSV<9A0BBS<VE2PKT<F1BBI<CX2SA
Sent: 110412/1124Z @:CX2SA.LAV.URY.SA #:64553 [Minas] FBB7.00e $:AMSATBB6208
From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: ARISSat-1 over SP (Mateusz)
2. Re: BBC - PLT Interference at VHF (David Barber)
3. Re: BBC - PLT Interference at VHF (Phil Karn)
4. Re: ARRISSat Reception 14.45 UTC (Anthony Monteiro)
5. Re: ARISSat-1 tlm decoder. (Anthony Monteiro)
6. Re: ARISSat-1 over SP (Alan P. Biddle)
7. ARISSat-1 09:27 UTC Nothing Heard (Peter Portanova)
8. Re: ARRISSat Reception 14.45 UTC (Phil Karn)
9. Still Nothing From ARISSat-1 In DO33 (B J)
10. Re: Still Nothing From ARISSat-1 In DO33 (B J)
11. Re: Still Nothing From ARISSat-1 In DO33 (Alan P. Biddle)
12. Re: Still Nothing From ARISSat-1 In DO33 (Dave Webb KB1PVH)
13. ARISSat-1 (Louis McFadin)
----------------------------------------------------------------------
Message: 1
Date: Tue, 12 Apr 2011 09:07:34 +0200
From: "Mateusz" <sq7dqx@xxxxxx.xxxx.xx>
Subject: [amsat-bb] Re: ARISSat-1 over SP
To: <amsat-bb@xxxxx.xxx>
Message-ID: <8DC9B156E94743518315118A34327202@xxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I was listening at midnight and I left equipment at night - nothing
recorded, nothing decoded - no signal.
Morning - the same.
Does anybody fell the same - they wasting our time ... ? It is not fair.
SQ7DQX
------------------------------
Message: 2
Date: Tue, 12 Apr 2011 08:52:14 +0100
From: "David Barber" <david.barber@xxxxxxxxxxxxx.xx.xx>
Subject: [amsat-bb] Re: BBC - PLT Interference at VHF
To: <amsat-bb@xxxxx.xxx>
Message-ID: <E21B6D25453A4F83BB1B3EAB55202F7F@xxxxxxxx>
Content-Type: text/plain; charset="us-ascii"
There are a series of these white papers, stretching back some years, all
written or co written by Jonathan Stott / BBC and highlighting the problems
associated with the various incarnations of PLT.
It is unfortunate that prior to PLT opposition becoming the 'fashionable'
campaign with which to associate, no one appeared to consider these papers,
or other evidence, seriously and the PLT genie was let free from the bottle.
********
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Trevor .
Sent: 11 April 2011 23:16
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] BBC - PLT Interference at VHF
This report is worth a read:
http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP195.pdf
73 Trevor M5AKA
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 3
Date: Tue, 12 Apr 2011 01:09:14 -0700
From: Phil Karn <karn@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: BBC - PLT Interference at VHF
To: david.barber@xxxxxxxxxxxxx.xx.xx
Cc: amsat-bb@xxxxx.xxx
Message-ID: <BANLkTim4+ZXWEPMFYqoTUFtMUvtZZCUsAw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Has PLT actually gone anywhere? I don't seem to hear much about it anymore.
The really sad part is that it represents such a huge lost opportunity for
the power companies. They're the *one* entity capable of providing some
badly-needed competition for the cablecos and the telcos. And they could
blow them both away by pulling fiber everywhere and selling it "dark" to
anyone and everyone who wants to sell a retail service over it.
The power companies would be wise to realize that their strength lies in
pulling cables over and under the streets and quickly fixing them when they
break. Let the computer geeks set up server rooms and help people with their
email problems. There's no shame in selling "dumb pipes". And there's
probably a lot more money in it too.
Yet all they wanna do is piddle around with this BPL/PLT stuff. They don't
seem to realize that their real assets aren't their wires carrying power to
their customers but their *rights of way* -- the poles, conduits,
underground vaults and such through which they could also pull optical
fiber. Some fiber cables are made without any conducting elements
specifically so they can be strung in the same bundle with uninsulated high
voltage transmission lines. And with zero EMI.
------------------------------
Message: 4
Date: Tue, 12 Apr 2011 04:59:14 -0400
From: Anthony Monteiro <aa2tx@xxxxxxx.xxx>
Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
To: karn@xxxx.xxx
Cc: amsat-bb@xxxxx.xxx
Message-ID: <201104120859.p3C8xDJj049014@xxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 02:50 AM 4/12/2011, Phil Karn wrote:
>To elaborate:
>...
>As I recall, ARISSat-1 data frames can be up to 512 bytes long. Ignoring
>HDLC flags, bit stuffing, CRC, etc, that's 4K bits. At a data rate of 500
>bps (the FEC is rate 1/2), 512 bytes will take 4096/500 = 8.192 seconds to
>transmit.
>
>8.192 seconds is longer than 7.232 seconds.
>
>Ooops.
>
>But wait, there's more. If the satellite sends a series of back-to-back 512
>byte frames, and the transmitter comes on too late after one has already
>started, you'll have to wait for it to end before you can begin decoding the
>next one. Meanwhile, the clock is quickly ticking down until the transmitter
>goes OFF again...
>
>Double oops.
Hi Phil,
That's why it doesn't work that way.
In low power mode, the transmission is started clean
every time. A single telemetry data frame is only 256
bytes so about 4 seconds of data. After the 1 frame, the
transmitter is left on until the interleaver is emptied.
73,
Tony AA2TX
------------------------------
Message: 5
Date: Tue, 12 Apr 2011 05:12:47 -0400
From: Anthony Monteiro <aa2tx@xxxxxxx.xxx>
Subject: [amsat-bb] Re: ARISSat-1 tlm decoder.
To: amsat-bb@xxxxx.xxx
Message-ID: <201104120912.p3C9CleY049846@xxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Hi David,
Bring up the Windows "Volume Control" and on the mixer
panel for playback, enable "Line In" or "Microphone",
whichever you are using for the input. You can adjust
the volume with the slider.
73,
Tony AA2TX
---
At 06:21 PM 4/11/2011, G0MRF@xxx.xxx wrote:
>Hi all.
>
>I have a minor (probably operator error) with the TLM software.
>
>Is there a way to get the audio to feed through to the PC speakers? I've
>tried Spectran and Spectraview without problem, but the ARISSat software
>does not appear to send audio out on my system. I cant hear the radio as I
>have a jack in the headphone socket which mutes the radio's speaker.
>
>The software is working. I can decode the CW callsign and locator of a 2m
>beacon and the level is controlled nicely with the windows 'microphone'
>record level.
>
>It's not muted
>It's got the correct input selected and the gain turned up.
>
>But.....no audio out...so I'm just setting the frequency by visually
>putting the signal in the right place.
>
>73
>
>David
>_______________________________________________
>Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
>Not an AMSAT-NA member? Join now to support the amateur satellite program!
>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 6
Date: Tue, 12 Apr 2011 04:21:28 -0500
From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Subject: [amsat-bb] Re: ARISSat-1 over SP
To: <amsat-bb@xxxxx.xxx>
Message-ID: <BEBAF0F0633A48B3BD9964259EC0F1F7@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
Definitely not a waste of time. All part of the game. Besides, I would
just be sleeping if I were not looking for a signal. ;)
Alan
WA4SCA
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Mateusz
Sent: Tuesday, April 12, 2011 2:08 AM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: ARISSat-1 over SP
I was listening at midnight and I left equipment at night - nothing
recorded, nothing decoded - no signal.
Morning - the same.
Does anybody fell the same - they wasting our time ... ? It is not fair.
SQ7DQX
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 7
Date: Tue, 12 Apr 2011 05:42:05 -0400
From: "Peter Portanova" <wb2oqq@xxxxxxx.xxx>
Subject: [amsat-bb] ARISSat-1 09:27 UTC Nothing Heard
To: <AMSAT-BB@xxxxx.xxx>
Message-ID: <99A4CF320A8B40458F3A04CFD0BA04C7@xxxx>
Content-Type: text/plain; format=flowed; charset=Windows-1252;
reply-type=original
Hello,
Happy Yuri Day to all, still waiting for the parade to begin.
73, Pete
WB2OQQ
------------------------------
Message: 8
Date: Tue, 12 Apr 2011 03:21:16 -0700
From: Phil Karn <karn@xxxxxxxx.xxx>
Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
To: Anthony Monteiro <aa2tx@xxxxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <BANLkTikXBGEdJ-waMez-zJPmiHfnBi7Q+g@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
> In low power mode, the transmission is started clean
> every time. A single telemetry data frame is only 256
> bytes so about 4 seconds of data. After the 1 frame, the
> transmitter is left on until the interleaver is emptied.
>
Excellent. I don't think anybody ever told me this. I'm glad somebody
noticed the problem.
Let's see...256 bytes is 2K bits. At rate 1/2, that encodes to 4K channel
symbols that take 4.096 sec to send, just as you said.
The very first symbol of the frame hits the modulator right away at T=0, but
the last symbol from the front of the frame won't come out until about T =
16.384 sec, the interleaver span.
4.096 sec after that (at T=20.48 sec elapsed time) the last symbol from the
end of the frame emerges. So you take 20.48 sec, start to finish, to
transmit 2k bits of user data for an effective data rate of 100 bps (vs 500
bps in continuous mode). And that's only counting the time the transmitter
is on.
Does the transmitter then go off at 20.48 sec, or does another frame start?
Where does the 40-60 sec interval come from?
During that 20.48 sec, 20,480 BPSK channel symbols are sent. But only 4K of
them actually represent FEC-encoded user data; the other 16K symbols
represent known (i.e., idle flag) bits and do not help decode the user data.
10*log10(4096/20480) is about -7 dB. I.e., a system that can operate at an
Eb/No of about 5.5 dB now requires an overall Eb/No of 12.5 dB. That's about
3 dB worse than uncoded BPSK...
On the other hand, it should still be somewhat more fade-resistant than
that...
Other than the obvious use of block interleaving, it is possible to improve
the efficiency of convolutional interleaving (and coding) on short
transmissions with "tail biting". You arrange the encoded symbols in a ring
and walk around it once. Then you pick an arbitrary point in the receive
buffer to start the Viterbi decoder, run it a few constraint lengths to get
it synchronized, and then run it around the ring once to actually decode the
packet. The tail of the packet gets interleaved with the head so you don't
have to fill and drain it with padding. It's actually just a way to
construct a block code (or interleaver) out of a convolutional structure.
You see why I wanted a command to turn interleaving on and off?
------------------------------
Message: 9
Date: Tue, 12 Apr 2011 04:04:12 -0700 (PDT)
From: B J <top_gun_canada@xxxxx.xxx>
Subject: [amsat-bb] Still Nothing From ARISSat-1 In DO33
To: amsat-bb@xxxxx.xxx
Message-ID: <815645.99978.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
I had a good view of the ISS during the pass, though.
73s
Bernhard VA6BMJ @ DO33FL
------------------------------
Message: 10
Date: Tue, 12 Apr 2011 04:08:10 -0700 (PDT)
From: B J <top_gun_canada@xxxxx.xxx>
Subject: [amsat-bb] Re: Still Nothing From ARISSat-1 In DO33
To: amsat-bb@xxxxx.xxx
Message-ID: <197755.60214.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
<snip>
> I had a good view of the ISS during
> the pass, though.
I forgot to mention that the pass was just before 1100 UTC.
<snip>
73s
Bernhard VA6BMJ @ DO33FL
------------------------------
Message: 11
Date: Tue, 12 Apr 2011 06:16:16 -0500
From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Subject: [amsat-bb] Re: Still Nothing From ARISSat-1 In DO33
To: "'B J'" <top_gun_canada@xxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <D3DB6AB2A6D741B7A188B8E5218B7946@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
Bernhard,
Nothing down here at EM65 on the 1102 UTC pass. Good geometry, though.
Fingers crossed we will have some definite word today.
Alan
WA4SCA
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of B J
Sent: Tuesday, April 12, 2011 6:04 AM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Still Nothing From ARISSat-1 In DO33
I had a good view of the ISS during the pass, though.
73s
Bernhard VA6BMJ @ DO33FL
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 12
Date: Tue, 12 Apr 2011 07:16:51 -0400
From: Dave Webb KB1PVH <kb1pvh@xxxxx.xxx>
Subject: [amsat-bb] Re: Still Nothing From ARISSat-1 In DO33
To: B J <top_gun_canada@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxx
Message-ID: <BANLkTi=RiLsX87wg=cHHY5T9rQ1db2t+wA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Nothing in FN42 on the 11:05 UTC pass 10? elevation.
Dave - KB1PVH
Sent from my Verizon Wireless DROID X
On Apr 12, 2011 7:14 AM, "B J" <top_gun_canada@xxxxx.xxx> wrote:
> I had a good view of the ISS during the pass, though.
>
> 73s
>
> Bernhard VA6BMJ @ DO33FL
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 13
Date: Tue, 12 Apr 2011 07:20:04 -0400
From: Louis McFadin <w5did@xxx.xxx>
Subject: [amsat-bb] ARISSat-1
To: amsat-bb@xxxxx.xxx
Message-ID: <E9CCAEFF-63D7-46EE-82C7-998EB8ED8C13@xxx.xxx>
Content-Type: text/plain; CHARSET=US-ASCII
Nothing heard on the 7 AM EDT 65 degree pass over Orlando.
On Apr 12, 2011, at 2:51 AM, amsat-bb-request@xxxxx.xxx wrote:
> Send AMSAT-BB mailing list submissions to
> amsat-bb@xxxxx.xxx
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://amsat.org/mailman/listinfo/amsat-bb
> or, via email, send a message with subject or body 'help' to
> amsat-bb-request@xxxxx.xxx
>
> You can reach the person managing the list at
> amsat-bb-owner@xxxxx.xxx
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of AMSAT-BB digest..."
>
>
> Today's Topics:
>
> 1. Re: The Need for Phonetics (Jim Shorney)
> 2. ARISsat-1 not heard (John Heath)
> 3. ARISSat-1 update (Gould Smith)
> 4. Re: ARRISSat Reception 14.45 UTC (Joe Fitzgerald)
> 5. Arissat still silent (P. Pakr)
> 6. Nothing Heard in VK of ARISSat-1 (Colin Hurst)
> 7. Nice view of ISS ... (Viktor Kudielka)
> 8. Re: ARRISSat Reception 14.45 UTC (Phil Karn)
> 9. Re: ARRISSat Reception 14.45 UTC (KF1BUZ)
> 10. Nothing Heard 2M ARISSat-1 9:32PM PDT (Clint Bradford)
> 11. Just an hour from now ... (Clint Bradford)
> 12. R50KEDR Heard on 14.190 (John Heath)
> 13. ARISSat-1 No Signal (John Spasojevich)
> 14. Re: ARISSat-1 No Signal (KF1BUZ)
> 15. Nothing here either: 0606z pass over California (Greg D.)
> 16. Nothing Heard From ARISSat-1 In DO33 (B J)
> 17. Not Heard 1106 PM PDT (Clint Bradford)
> 18. satellite average elevation (Bob- W7LRD)
> 19. Nothing heard over Nashville 0610 (Alan P. Biddle)
> 20. Re: ARRISSat Reception 14.45 UTC (Phil Karn)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 11 Apr 2011 19:03:22 -0500
> From: "Jim Shorney" <jshorney@xxxxxxxxx.xxx>
> Subject: [amsat-bb] Re: The Need for Phonetics
> To: "amsat-bb" <amsat-bb@xxxxx.xxx>
> Message-ID: <20110412000315.B8E5816E398@xxxxxx.xxxxxxxxx.xxx>
> Content-Type: text/plain; charset="iso-8859-1"
>
> On Mon, 11 Apr 2011 14:17:49 -0700, Jeff Moore wrote:
>
>> <== Could it be that they understand the quicksand you're standing on?
>
>
> No. We know from long experience (35+ years in my case) that Glen is right.
>
> 73
>
> -Jim
>
>
> --
> Ham Radio NU0C
> Lincoln, Nebraska, U.S.S.A.
> TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A,
GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time!
>
> "Give a man a URL, and he will learn for an hour; teach him to Google, and
he will learn for a lifetime."
>
> HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/
> http://incolor.inetnebr.com/jshorney
> http://www.nebraskaghosts.org
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 12 Apr 2011 01:22:39 +0100 (BST)
> From: John Heath <g7hia@xxxxxxxxxx.xxx>
> Subject: [amsat-bb] ARISsat-1 not heard
> To: Amsat <amsat-bb@xxxxx.xxx>
> Message-ID: <330370.94421.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
> Content-Type: text/plain; charset=iso-8859-1
>
> 0107? AOS pass in range UK - nothing heard on 145.950
>
> 73 john g7hia
>
> ------------------------------
>
> Message: 3
> Date: Mon, 11 Apr 2011 20:35:42 -0400
> From: "Gould Smith" <gouldsmi@xxxxxxxxx.xxx>
> Subject: [amsat-bb] ARISSat-1 update
> To: <amsat-bb@xxxxx.xxx>
> Message-ID: <0EE1E8CB77EF40158B1BCB10C560994B@xxxxxxxxxxx>
> Content-Type: text/plain; charset="iso-8859-1"
>
> As Armando, N8IGJ noted in his earlier email, NASA as published an update
of today's activities ( it can be found at
:http://www.nasa.gov/directorates/somd/reports/iss_reports/index.html)
.Contained this document is a section about ARISSat
>
> Dmitri performed hardware setup and test activation of the TEKh-43
Radioskaf-B "Kedr" microsatellite in the MRM2 Poisk module, connecting it to
an 825M3 Orlan battery and checking out its 430 MHz transmitter from the
satellite control panel. [The small satellite was named Kedr in honor of the
call sign of Yuri Gagarin. It will be activated onboard the station
tomorrow, April 12, i.e., Cosmonautics Day, when the world celebrates the
anniversaries of the first human flight into space and the first Space
Shuttle flight. Development, manufacturing and launch of Kedr is the first
phase in Russia's integrated program approved by UNESCO, with the goal to
create and operate mini-satellites with a mass less than 100 kg by combined
efforts of students across the world. Once Kedr is activated, it will
transmit 25 greetings in 15 languages, pictures of Earth, and telemetry data
from science hardware and support systems, as well as historical audio
recordings. 50 years after Gagarin's !
fl!
> ight all ham radio operators across the world thus will have a unique
opportunity to hear the famous "Poyekhali" (Let's Go!) from Earth orbit.]
>
> Some clarifications:
> ARISSat-1, RadioSkaf-V, RadioSkaf-B, Kedr are all names for the same
satellite.
> It is doubtful that the satellite will transmit pictures of earth as it is
inside the ISS.
> ARISSat-1 only transmits on 2M. The ARISS team has arranged for the
TM-D700 transceiver aboard the ISS to also transmit the ARISSat signals on
437.55 MHz.
> There are 24 different messages that will transmit in a sequence, one of
which is the Gagarin-ground station conversation.
> The crew operates on UTC time and sleeps from 2130Z - 0600Z usually so
probably no activity until after 0600Z
> The 12 April schedule found at
http://www.nasa.gov/pdf/534825main_041211_tl.pdf doesn't specifically list
an activity to turn on ARISsat-1
> Keep listening, we'll let you know more as we know more.
>
> 73,
> Gould, WA4SXM
>
> ------------------------------
>
> Message: 4
> Date: Mon, 11 Apr 2011 20:47:28 -0400
> From: Joe Fitzgerald <jfitzgerald@xxxx.xxx.xxx>
> Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
> To: amsat-bb@xxxxx.xxx
> Message-ID: <4DA3A120.9040701@xxxx.xxx.xxx>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 4/11/2011 1:44 PM, Phil Karn wrote:
>> Since it's already connected to the station antenna, it sure would be nice
>> if they could just plug it directly into the ISS power supply, switch it on
>> full duty cycle, and just *leave* it for a couple of, oh, years.
>
> Phil,
>
> I am curious to see how your BPSK1000 fares on a rapidly tumbling
> platform. Let's hope ISS doesn't start tumbling more than once per orbit!
>
> If you do convince them to leave the ISS powered up on board ISS, we
> could evaluate rapit deep fades in the channel by putting middle school
> students in charge of holding an arrow antenna.
>
> -Joe KM1P
>
>
> ------------------------------
>
> Message: 5
> Date: Tue, 12 Apr 2011 01:02:59 +0200
> From: "P. Pakr" <p.pakr@xxxxxx.xx>
> Subject: [amsat-bb] Arissat still silent
> To: amsat-bb@xxxxx.xxx
> Message-ID: <20110411220258.6CDE08A8006@xxx.xxxxxxxx.xxxx>
> Content-Type: text/plain ; charset="UTF-8"
>
> Next pass over Czech, nothing heard here :-(
> 73! Petr
>
>
> ------------------------------
>
> Message: 6
> Date: Tue, 12 Apr 2011 10:52:47 +0930
> From: "Colin Hurst" <cjhurst@xxxxxxx.xxx.xx>
> Subject: [amsat-bb] Nothing Heard in VK of ARISSat-1
> To: "amsat-bb" <amsat-bb@xxxxx.xxx>
> Message-ID: <C8B6CE92B219472DBF5394B1577A6723@xxxxxx>
> Content-Type: text/plain; charset="us-ascii"
>
> Had a nice pass at 0045utc 12/4/2011, 67 degrees elevation.
> No signals heard.
> 73
> Colin VK5HI
>
>
>
> ------------------------------
>
> Message: 7
> Date: Tue, 12 Apr 2011 03:39:11 +0000
> From: Viktor Kudielka <viktor.kudielka@xxxx.xxx>
> Subject: [amsat-bb] Nice view of ISS ...
> To: amsat-bb@xxxxx.xxx
> Message-ID: <20110412033911.GD26119@xxxxxx.xxx>
> Content-Type: text/plain; charset=us-ascii
>
> ... over Vienna at 03:25UTC with 47 degrees elevation.
> Automatic antenna tracking seems to be nearly perfect,
> but no signal ?
> The CW decoder of ARISSatTLM produced a random string of
> characters including ...HIHI...
> 73, Viktor OE1VKW
>
>
>
> ------------------------------
>
> Message: 8
> Date: Mon, 11 Apr 2011 20:58:54 -0700
> From: Phil Karn <karn@xxxxxxxx.xxx>
> Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
> To: Joe Fitzgerald <jfitzgerald@xxxx.xxx.xxx>
> Cc: amsat-bb@xxxxx.xxx
> Message-ID: <BANLkTi=gMJKZbivTEVeoP+zV2+Wj_mA1xw@xxxx.xxxxx.xxx>
> Content-Type: text/plain; charset=UTF-8
>
> On Mon, Apr 11, 2011 at 5:47 PM, Joe Fitzgerald
<jfitzgerald@xxxx.xxx.xxx>wrote:
>
>>
>> I am curious to see how your BPSK1000 fares on a rapidly tumbling
>> platform. Let's hope ISS doesn't start tumbling more than once per orbit!
>>
>
> It's a pretty sensitive mode, but it still won't work with a zero-watt
> transmitter.
>
>
>>
>> If you do convince them to leave the ISS powered up on board ISS, we
>> could evaluate rapit deep fades in the channel by putting middle school
>> students in charge of holding an arrow antenna.
>>
>>
> My concern is that the on/off cycling won't play well with my convolutional
> interleaver. It takes 16.384 seconds to fill the interleaver at AOS. You
> might get decoded data up to 8 seconds earlier than that if what you do get
> is very clean, but there's little margin for additional error correction.
>
> And when the transmitter switches off, the interleaver will drain over
> 16.384 seconds as it fills with noise. If the signal in the last 16.384
> seconds before switch-off is unusually strong, you may be able to decode
> data up to 8 seconds before LOS. But anywhere from 8 to 16 seconds will be
> chopped off *each end* of each already very short 40-60 second
> transmission.
>
> I designed this signal to deal well with occasional deep fades lasting up to
> 1-1.5 seconds -- not for total "fades" lasting 2 minutes at a time. Had I
> known that this "emergency low power mode" was actually going to be used, I
> would have designed the whole mode completely differently, with block
> interleaving aligned to the transmit on/off times.
>
> The golden rule of the modem designer: "know your channel". Optimizing for
> one impairment usually pessimizes it for something else.
>
>
> ------------------------------
>
> Message: 9
> Date: Mon, 11 Apr 2011 21:22:28 -0700
> From: KF1BUZ <kf1buz@xxxxx.xxx>
> Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
> To: <karn@xxxx.xxx>, "'Joe Fitzgerald'" <jfitzgerald@xxxx.xxx.xxx>
> Cc: amsat-bb@xxxxx.xxx
> Message-ID: <00f101cbf8c9$3ceed0b0$b6cc7210$@xxx>
> Content-Type: text/plain; charset="us-ascii"
>
> Well its 421 am they will be awake around 0600 am utc.. 2 hours from now,
> then we will see if they flippa da switcha
>
> Kf1buz
>
> -----Original Message-----
> From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
> Behalf Of Phil Karn
> Sent: Monday, April 11, 2011 8:59 PM
> To: Joe Fitzgerald
> Cc: amsat-bb@xxxxx.xxx
> Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
>
> On Mon, Apr 11, 2011 at 5:47 PM, Joe Fitzgerald
> <jfitzgerald@xxxx.xxx.xxx>wrote:
>
>>
>> I am curious to see how your BPSK1000 fares on a rapidly tumbling
>> platform. Let's hope ISS doesn't start tumbling more than once per orbit!
>>
>
> It's a pretty sensitive mode, but it still won't work with a zero-watt
> transmitter.
>
>
>>
>> If you do convince them to leave the ISS powered up on board ISS, we
>> could evaluate rapit deep fades in the channel by putting middle
>> school students in charge of holding an arrow antenna.
>>
>>
> My concern is that the on/off cycling won't play well with my convolutional
> interleaver. It takes 16.384 seconds to fill the interleaver at AOS. You
> might get decoded data up to 8 seconds earlier than that if what you do get
> is very clean, but there's little margin for additional error correction.
>
> And when the transmitter switches off, the interleaver will drain over
> 16.384 seconds as it fills with noise. If the signal in the last 16.384
> seconds before switch-off is unusually strong, you may be able to decode
> data up to 8 seconds before LOS. But anywhere from 8 to 16 seconds will be
> chopped off *each end* of each already very short 40-60 second
> transmission.
>
> I designed this signal to deal well with occasional deep fades lasting up to
> 1-1.5 seconds -- not for total "fades" lasting 2 minutes at a time. Had I
> known that this "emergency low power mode" was actually going to be used, I
> would have designed the whole mode completely differently, with block
> interleaving aligned to the transmit on/off times.
>
> The golden rule of the modem designer: "know your channel". Optimizing for
> one impairment usually pessimizes it for something else.
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
>
> ------------------------------
>
> Message: 10
> Date: Mon, 11 Apr 2011 21:47:09 -0700
> From: Clint Bradford <clintbradford@xxx.xxx>
> Subject: [amsat-bb] Nothing Heard 2M ARISSat-1 9:32PM PDT
> To: AMSAT BB <amsat-bb@xxxxx.xxx>
> Message-ID: <4FF01222-2099-4C54-8C94-D658CFE02E7C@xxx.xxx>
> Content-Type: text/plain; CHARSET=US-ASCII
>
> Another poor pass for me ... nothing heard.
>
> BUT AT 11:06PM PDT - a whopper of a pass. Followed by a pass in the
morning that should be VISIBLE!
>
> ("Honey, brew another pot o' coffee, will you please?")
>
> Clint, K6LCS
> 909-241-7666 - cell
>
>
> ------------------------------
>
> Message: 11
> Date: Mon, 11 Apr 2011 22:09:42 -0700
> From: Clint Bradford <clintbradford@xxx.xxx>
> Subject: [amsat-bb] Just an hour from now ...
> To: AMSAT BB <amsat-bb@xxxxx.xxx>
> Message-ID: <D8875A02-4FA0-4E30-A5FF-1EBE90BADE92@xxx.xxx>
> Content-Type: text/plain; CHARSET=US-ASCII
>
> Added a photo of me working (unsuccessfully) a pass of the ISS this
evening (9:32PM PDT, Riverside, CA DM13).
>
> In the background, FirstOrbit.org's incredible film that will be released
to the world tomorrow - a re-creation of Yuri's 108-minute flight, taken by
modern cameras aboard the ISS.
>
> http://gallery.me.com/clintbradford#100077
>
> Clint, K6LCS
> Skype - clintbradford
>
>
> ------------------------------
>
> Message: 12
> Date: Tue, 12 Apr 2011 06:20:53 +0100 (BST)
> From: John Heath <g7hia@xxxxxxxxxx.xxx>
> Subject: [amsat-bb] R50KEDR Heard on 14.190
> To: Amsat <amsat-bb@xxxxx.xxx>
> Message-ID: <951449.92923.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
> Content-Type: text/plain; charset=utf-8
>
> 0520 UTC
>
> The gagarin station R50KEDR on 14.190 working split listening 5 up.
>
> Weak signal at my QTH in southern England
>
> 73 john g7hia
>
> ------------------------------
>
> Message: 13
> Date: Tue, 12 Apr 2011 00:08:25 -0500
> From: John Spasojevich <johnag9d@xxxxx.xxx>
> Subject: [amsat-bb] ARISSat-1 No Signal
> To: amsat-bb@xxxxx.xxx
> Message-ID: <BANLkTinhnB5fFMb7TbOPUUOacrF3pie2pw@xxxx.xxxxx.xxx>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Nothing heard on the 0437 UTC pass in Montgomery, IL 76 degrees elevation,
> nice night though.
>
> John - AG9D
>
>
> ------------------------------
>
> Message: 14
> Date: Mon, 11 Apr 2011 23:16:30 -0700
> From: KF1BUZ <kf1buz@xxxxx.xxx>
> Subject: [amsat-bb] Re: ARISSat-1 No Signal
> To: "'John Spasojevich'" <johnag9d@xxxxx.xxx>, <amsat-bb@xxxxx.xxx>
> Message-ID: <00f201cbf8d9$2accaf00$80660d00$@xxx>
> Content-Type: text/plain; charset="us-ascii"
>
> Nothing heard over reno, no packet or anything..
>
> Slacking space doods!!
> Kf1buz
>
> -----Original Message-----
> From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
> Behalf Of John Spasojevich
> Sent: Monday, April 11, 2011 10:08 PM
> To: amsat-bb@xxxxx.xxx
> Subject: [amsat-bb] ARISSat-1 No Signal
>
> Nothing heard on the 0437 UTC pass in Montgomery, IL 76 degrees elevation,
> nice night though.
>
> John - AG9D
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
>
>
>
> ------------------------------
>
> Message: 15
> Date: Mon, 11 Apr 2011 23:23:27 -0700
> From: "Greg D." <ko6th_greg@xxxxxxx.xxx>
> Subject: [amsat-bb] Nothing here either: 0606z pass over California
> To: <amsat-bb@xxxxx.xxx>
> Message-ID: <BLU133-W298B2A1BBC173A8237AC00A9AB0@xxx.xxx>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> No signal on 145.950 here in Cal. With my luck they probably started the
15 min timer just before LOS...
>
> By the way, confirming the earlier post about inconsistent KEPs. Gpredict
updates from Celestrak, and was slightly behind Predict which I had loaded
from Amsat.org website. (I use Gpredict for pass prediction and eye candy
during a pass; predict drives my rotor and Doppler shift radio client.)
>
> Greg KO6TH
>
>
>
> ------------------------------
>
> Message: 16
> Date: Mon, 11 Apr 2011 23:25:29 -0700 (PDT)
> From: B J <top_gun_canada@xxxxx.xxx>
> Subject: [amsat-bb] Nothing Heard From ARISSat-1 In DO33
> To: amsat-bb@xxxxx.xxx
> Message-ID: <794603.7473.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
> Content-Type: text/plain; charset=us-ascii
>
> I listened until 0620 UTC but it was a low-elevation pass. The next 3
will be over 30 degrees.
>
> 73s
>
> Bernhard VA6BMJ @ DO33FL
>
>
>
> ------------------------------
>
> Message: 17
> Date: Mon, 11 Apr 2011 23:35:36 -0700
> From: Clint Bradford <clintbradford@xxx.xxx>
> Subject: [amsat-bb] Not Heard 1106 PM PDT
> To: AMSAT BB <amsat-bb@xxxxx.xxx>
> Message-ID: <0816DB2F-0E77-455C-ABC2-E58B55990C4C@xxx.xxx>
> Content-Type: text/plain; CHARSET=US-ASCII
>
> Darn .... Nada heard on an excellent pass of the ISS at 1106PM PDT.
>
> But I think the astronauts were just awakened at the top o' the hour.
>
> OK - 5:30-ish AM PDT next pass over Southern CA DM13-land!
>
> Clint
> Skype - clintbradford
>
>
> ------------------------------
>
> Message: 18
> Date: Tue, 12 Apr 2011 06:35:48 +0000 (UTC)
> From: Bob- W7LRD <w7lrd@xxxxxxx.xxx>
> Subject: [amsat-bb] satellite average elevation
> To: amsat-bb@xxxxx.xxx
> Message-ID:
>
<1639302076.3920933.1302590148277.JavaMail.root@xxxxxxx.xxxxxxxxxx.xx.xxxx.xx
xxxxx.xxx>
>
> Content-Type: text/plain; charset=utf-8
>
>
>
> I saw on this bb a site or note that shows the overall?average
elevatation.? As I remember it elevation is surprisingly low for most
passes.? Where can I find it?
>
> 73 Bob W7LRD
>
>
> ------------------------------
>
> Message: 19
> Date: Tue, 12 Apr 2011 01:41:15 -0500
> From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
> Subject: [amsat-bb] Nothing heard over Nashville 0610
> To: "AMSAT-BB" <amsat-bb@xxxxx.xxx>
> Message-ID: <0D3F14EBAC99494FA86A73A7FD1D8543@xxxxxx>
> Content-Type: text/plain; charset="us-ascii"
>
> All,
>
> Silence over Nashville on the 0610 UTC pass. All but 2 of the passes during
> the scheduled period of activation will be "in the weeds" from an elevation
> standpoint at my QTH.
>
> Did get a nice I/Q recording of the passband, though.
>
>
> Alan
> WA4SCA
>
> -----------------------------------
>
> The prospect of domination of the
> nation's scholars by Federal employment,
> project allocations, and the power of money
> is ever present - and is gravely to be
> regarded.
>
> President Dwight D. Eisenhower
>
>
>
>
> ------------------------------
>
> Message: 20
> Date: Mon, 11 Apr 2011 23:50:44 -0700
> From: Phil Karn <karn@xxxxxxxx.xxx>
> Subject: [amsat-bb] Re: ARRISSat Reception 14.45 UTC
> To: Joe Fitzgerald <jfitzgerald@xxxx.xxx.xxx>
> Cc: amsat-bb@xxxxx.xxx
> Message-ID: <BANLkTimUmhaTC0BhCvuQaid90A4DmFWdrQ@xxxx.xxxxx.xxx>
> Content-Type: text/plain; charset=UTF-8
>
> To elaborate:
>
> BPSK-1000 uses "convolutional interleaving" with a depth of 16,384 symbols.
> The symbol rate is 1 kHz (1,000 symbols/sec) so it takes 16.384 seconds for
> a data symbol to pass through both the transmit and receive interleave
> buffers. The transmitter delay changes a lot from one symbol to the next,
> but every symbol experiences the same *total* (transmitter + receiver)
> delay: 16,384 symbol times or 16.384 seconds. The idea of any interleaver is
> to chop up (short) fades and spread them out in time so that they can be
> easily corrected by the Viterbi error correction algorithm (which deals well
> with random thermal noise but not with burst errors).
>
> The usual rule of thumb is that an interleaver can easily handle a complete
> fade lasting up to 10% of its length, as long as you give it time to recover
> between fades. That would be 1.6 seconds, which seemed plenty long for a
> continuously transmitting LEO spacecraft on 2 meters.
>
> Of course, you pay a price in delay -- there's no way around it. I have
> Sirius Satellite Radio in my car, and it always cuts out 4 seconds *after* I
> drive into the parking garage at work. It doesn't come back until (at least)
> 4 seconds *after* I drive out and it sees the satellite(s) again. The reason
> is exactly the same -- an interleaver that takes care of brief fades but not
> the really long ones caused by driving into a parking garage.
>
> I chose convolutional interleaving for BPSK-1000 because it has half the
> delay of block interleaving for the same fade performance.
>
> Convolutional interleavers also operate continuously, a good match to
> ARISSat-1's continuous transmitter. At AOS, your deinterleaver is still full
> of noise received earlier; it takes 16.384 seconds to flush it all out and
> feed "solid" data to the decoder. During that time, it ramps from pure noise
> to pure signal, and at some point it starts correcting what it sees.
> Depending on how strong the signal is, that may happen before the flushing
> is complete. I.e., it might reconstruct some of the missing symbols sent
> before your AOS.
>
> Similarly there is a slow ramp from solid signal down to pure noise over
> 16.384 seconds at LOS.
>
> See how this helps handle fading? Even an abrupt, complete fade starts the
> same, slow 16-second ramp down from signal to noise. If the fade ends only a
> second or two later, the rampdown won't have progressed very far and the
> decoder will still see mostly signal when the trend reverses and ramps back
> up to pure signal. That takes a few extra seconds, but the error correction
> can easily handle it all -- as long as the fade isn't *too* long.
> Interleaving takes a signal that may be solid one moment and gone the next
> and smooths it out so that the signal-to-noise ratio changes only slowly. It
> literally averages the signal-to-noise ratio.
>
> Since even a short LEO pass is usually several minutes long, these 16 second
> fill/drain intervals didn't seem like a big deal. Besides, we've already had
> a similar problem since the old days of the uncoded Phase III block
> telemetry format. You might have AOS in the middle of a frame and have to
> wait for the next one to start before you can decode anything. Interleaving
> isn't really any worse.
>
> The problem is that I didn't count on having the transmitter turned on for
> only 40-60 seconds at a time. So....if the transmissions are only 40 sec,
> and if you have to wait 16.384 seconds for the interleaver to fill, and you
> can't rely on the last 16.384 seconds as the interleaver drains, that leaves
> 40 - 2*16.384 = 7.232 seconds of solid, noise-free "middle" to work with.
>
> As I recall, ARISSat-1 data frames can be up to 512 bytes long. Ignoring
> HDLC flags, bit stuffing, CRC, etc, that's 4K bits. At a data rate of 500
> bps (the FEC is rate 1/2), 512 bytes will take 4096/500 = 8.192 seconds to
> transmit.
>
> 8.192 seconds is longer than 7.232 seconds.
>
> Ooops.
>
> But wait, there's more. If the satellite sends a series of back-to-back 512
> byte frames, and the transmitter comes on too late after one has already
> started, you'll have to wait for it to end before you can begin decoding the
> next one. Meanwhile, the clock is quickly ticking down until the transmitter
> goes OFF again...
>
> Double oops.
>
> Now this probably overstates the problem a bit. Being the engineer that I
> am, this is a very conservative analysis -- I made the most pessimistic
> assumption at each step. After all, I was stunned when somebody streamed
> BPSK-1000 over the net with a lossy MP3 encoder and it *decoded*; I never
> thought that would work.
>
> Error correction can fill in for a remarkable variety of ills. In reality,
> the satellite won't send a continuous stream of 512 byte frames. In reality,
> the key-down intervals may be more than 40 seconds. So I actually won't be
> too terribly surprised if the thing actually works. But it won't perform
> anything like it will when the satellite is eventually operated in its
> intended 100% duty cycle mode.
>
>
> ------------------------------
>
> _______________________________________________
> Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
> http://amsat.org/mailman/listinfo/amsat-bb
>
>
> End of AMSAT-BB Digest, Vol 6, Issue 207
> ****************************************
Lou McFadin
W5DID
ARISS US Hardware manager
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 6, Issue 208
****************************************
Read previous mail | Read next mail
| |
