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CX2SA > SATDIG 01.10.12 21:05l 366 Lines 12146 Bytes #999 (0) @ WW
BID : AMSATBB7326
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Subj: AMSAT-BB-digest V7 326
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Sent: 121001/1903Z @:CX2SA.SAL.URY.SA #:2490 [Salto] FBB7.00e $:AMSATBB7326
From: CX2SA@CX2SA.SAL.URY.SA
To : SATDIG@WW
Today's Topics:
1. Ideal AMSAT FM Transponder (Robert Bruninga)
2. Re: Ideal AMSAT FM Transponder (Walter Holmes)
3. Re: Ideal AMSAT FM Transponder (Tony Langdon)
4. maximum AO-7 distance (Bob- W7LRD)
5. Re: Ideal AMSAT FM Transponder (Trevor .)
6. ISS CubeSat deployment Oct 4 (Trevor .)
7. Re: maximum AO-7 distance - with link to image (Thomas Doyle)
8. Re: Ideal AMSAT FM Transponder (Robert Bruninga)
9. The first satellite, Sputnik-1 (Mineo Wakita)
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Message: 1
Date: Sun, 30 Sep 2012 15:49:53 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: Amsat - BBs <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Ideal AMSAT FM Transponder
Message-ID: <15f974de343cfadf5e95caf500c7104e@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
The ideal AMSAT FM transponder for a cubesat is the PSK-31 transponder
being developed for the Naval Academy PSAT mission.
With an FM downlink, anyone can receive it with an HT and a laptop with
PSK-31 software. And anyone with a 10m PSK-31 uplink can transmit to it.
The reason it is ideal is that it is a multi-user transponder supporting
up to 30 users at the same time. Everyone can transmit horizon-to-horizon
and see everyone else. A big QSO party in the sky:
http://aprs.org/psat/PSK31-DESIGN-NOTES.html
And since it is FM, Everyone tuned into the downlink SEES THE SAME
WATERFALL and sees EXACTLY where they are in the downlink. A small uplink
doppler adjustment can keep each station locked to his chosen channel in
the passband.
Everyone can talk to everyone if they want, or go one-on-one too.
The SSB uplink and UHF downlink transponder fits on a smaller than 3"x3"
circuit board being developed by Mirek Kasal at Brno University.
If we could just get more Cubeats to fly these things, we would have all
the joys of multi-user transponders, and yet they fit well in any cubesat.
The ONLY problem is the HF wire antenna. Ours is going to be a 4 or 6'
whip of Nitinol Wire.
In addition to thes PSK-31 transponder, PSAT also supports the usual APRS
AX.25 transponder on 145.825 too. Launch is planned for Summer 2013.
Bob, WB4aPR
------------------------------
Message: 2
Date: Sun, 30 Sep 2012 15:47:01 -0500
From: "Walter Holmes" <Walterh@xxxx.xxx>
To: "'Robert Bruninga'" <bruninga@xxxx.xxx>, "'Amsat - BBs'"
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Ideal AMSAT FM Transponder
Message-ID: <005801cd9f4c$bddb2900$39917b00$@xxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Hey Bob,
This might also be a great project for balloon launches as well, to be able
to test all the ground station setups.
Any idea if these transponders will be made available to others after this
project is completed ?
It appears that the Small Wonder Labs' PSK device is no longer available,
pending a replacement that's in the works.
Take care,
Walter/K5WH
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of Robert Bruninga
Sent: Sunday, September 30, 2012 2:50 PM
To: Amsat - BBs
Subject: [amsat-bb] Ideal AMSAT FM Transponder
The ideal AMSAT FM transponder for a cubesat is the PSK-31 transponder being
developed for the Naval Academy PSAT mission.
With an FM downlink, anyone can receive it with an HT and a laptop with
PSK-31 software. And anyone with a 10m PSK-31 uplink can transmit to it.
The reason it is ideal is that it is a multi-user transponder supporting up
to 30 users at the same time. Everyone can transmit horizon-to-horizon and
see everyone else. A big QSO party in the sky:
http://aprs.org/psat/PSK31-DESIGN-NOTES.html
And since it is FM, Everyone tuned into the downlink SEES THE SAME WATERFALL
and sees EXACTLY where they are in the downlink. A small uplink doppler
adjustment can keep each station locked to his chosen channel in the
passband.
Everyone can talk to everyone if they want, or go one-on-one too.
The SSB uplink and UHF downlink transponder fits on a smaller than 3"x3"
circuit board being developed by Mirek Kasal at Brno University.
If we could just get more Cubeats to fly these things, we would have all the
joys of multi-user transponders, and yet they fit well in any cubesat.
The ONLY problem is the HF wire antenna. Ours is going to be a 4 or 6'
whip of Nitinol Wire.
In addition to thes PSK-31 transponder, PSAT also supports the usual APRS
AX.25 transponder on 145.825 too. Launch is planned for Summer 2013.
Bob, WB4aPR
_______________________________________________
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: Mon, 01 Oct 2012 06:49:40 +1000
From: Tony Langdon <vk3jed@xxxxx.xxx>
To: Robert Bruninga <bruninga@xxxx.xxx>, Amsat - BBs
<amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Ideal AMSAT FM Transponder
Message-ID: <5068b06c.a288440a.59a8.4660@xx.xxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 05:49 AM 10/1/2012, Robert Bruninga wrote:
>The ideal AMSAT FM transponder for a cubesat is the PSK-31 transponder
>being developed for the Naval Academy PSAT mission.
>
>With an FM downlink, anyone can receive it with an HT and a laptop with
>PSK-31 software. And anyone with a 10m PSK-31 uplink can transmit to it.
This sounds like an interesting bird to try.
73 de VK3JED / VK3IRL
http://vkradio.com
------------------------------
Message: 4
Date: Mon, 1 Oct 2012 06:47:13 +0000 (UTC)
From: Bob- W7LRD <w7lrd@xxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] maximum AO-7 distance
Message-ID:
<1013271167.66790.1349074033608.JavaMail.root@xxxxxxx.xxxxxxxxxx.xx.xxxx.xxxxx
xx.xxx>
Content-Type: text/plain; charset=utf-8
to my AO-7 afictionados...what is the maximum distance one can work edge to
edge, and how did you figure that out?
73 Bob W7LRD
------------------------------
Message: 5
Date: Mon, 1 Oct 2012 12:07:58 +0100 (BST)
From: "Trevor ." <m5aka@xxxxx.xx.xx>
To: Amsat - BBs <amsat-bb@xxxxx.xxx>, Robert Bruninga
<bruninga@xxxx.xxx>
Subject: [amsat-bb] Re: Ideal AMSAT FM Transponder
Message-ID:
<1349089678.28448.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
--- On Sun, 30/9/12, Robert Bruninga <bruninga@xxxx.xxx> wrote:
> With an FM downlink, anyone can receive it with an HT and a
> laptop with PSK-31 software.? And anyone with a 10m PSK-31 uplink
> can transmit to it.
> The SSB uplink and UHF downlink transponder fits on a
> smaller than 3"x3" circuit board
Sounds great Bob.
I presume the reason for UHF downlink rather than 145 MHz, with it's lower
Doppler shift, is due to other mission constraints ?
BTW is the uplink in the amateur satellite segment of 10m (29.3-29.5) or
down at the bottom of the band ?
Hopefully IARU / ARRL will be successful in getting an Amateur-satellite
allocation at 50 MHz since the CubeSat antenna problem would be easier to
address on those frequencies.
A thought occurs to me. We use Oscar-7 mode B with its input outside the
bands allocated to the Amateur-satellite Service. We can use it because
various National Societies have negotiated with their Regulator to allow its
use by amateurs in their country. I wonder if a similar approach would
enable the use of 50 MHz as an uplink band prior to any WRC changes ?
73 Trevor M5AKA
------------------------------
Message: 6
Date: Mon, 1 Oct 2012 13:41:56 +0100 (BST)
From: "Trevor ." <m5aka@xxxxx.xx.xx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] ISS CubeSat deployment Oct 4
Message-ID:
<1349095316.61709.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
It is reported that the ISS CubeSats will be deployed on October 4 at 1435 UT
See http://www.amsat-uk.org/?p=10119
73 Trevor M5AKA
AMSAT-UK http://www.amsat-uk.org/
----
------------------------------
Message: 7
Date: Mon, 1 Oct 2012 08:32:33 -0500
From: Thomas Doyle <tomdoyle1948@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: maximum AO-7 distance - with link to image
Message-ID:
<CAHnRQRJA6JBpL0mmh6brQ8FgZbCXV4HAhZbey-tU6B7uKs0cEw@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Bob,
Since the height above ground varies due to the elliptical nature of
orbits the max range also varies. Where the two stations are located
relative to the apogee of the orbit can also come into play. If you
are on the wrong side of the earth when the satellite is at its apogee
that could be a problem.
Here is my best shot at the range of max distances for AO-07 - compare
them to numbers you get from other folks and let me know what you
find. My numbers could be and are probably wrong.
http://www.tomdoyle.org/ao-07.png
73 W9KE tom...
--
Sent from my computer.
tom ...
------------------------------
Message: 8
Date: Mon, 1 Oct 2012 11:14:00 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: Amsat - BBs <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Ideal AMSAT FM Transponder
Message-ID: <c93b2e439b3c41e2628eb2edf073cccc@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
> I presume the reason for UHF downlink rather than
> 145 MHz, with it's lower Doppler shift, is due to
> other mission constraints ?
Yes, avoid QRM to the 145.825 APRS transponder.
> BTW is the uplink in the amateur satellite segment
> of 10m (29.3-29.5) or down at the bottom of the band ?
Bottom segement. Think of it as a UHF linked band monitor for existing
PSK31 operation on 10m usually between 28.120 and 28.123 MHz. The entire
band is authorized by the ITU for satcom, though most band plans protect
downlinks above 29.3 MHz.
> This might also be a great project for balloon launches...
> to be able to test all the ground station setups.
> Any idea if these transponders will be made available
> to others after this project is completed ?
It will be up to Brno University and Mirek..
> It appears that the Small Wonder Labs' PSK device
> is no longer available, pending a replacement that's in the works.
Yes, we used a Brno module for the first flight back in 2006 on PCSAT2 but
then used a Small Wonder Labs PSK transceiver on the RAFT satellite in
2007.
The #1 hardest thing on making this system work, is getting the antenna
tuned and resonant. This is a real challenge, because you cannot get
inside the 4" cubesat with any instrumentation to tune for resonance.
ANYTHING you connect to the spacecraft and antennas completely messes up
the affect of the counterpoise.
The best method we have found is to just build the transponder, and then
tweak a tuning element via a hole in the spacecraft until you can hear the
best signal from the transponder listening to normal signals on 10m. Oh,
and having the whole set up FAR away from the ground and ANYTHING else...
It is a long and tedioius process.
We just did a preliminary EZNEC analysis, and the antenna impedance is
something like Z = 2 - J1100 using a 6 foot wire.
Bob, WB4APR
------------------------------
Message: 9
Date: Tue, 2 Oct 2012 01:03:31 +0900
From: "Mineo Wakita" <ei7m-wkt@xxxxxxxxx.xx.xx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] The first satellite, Sputnik-1
Message-ID: <8C96E50C159F42829C89EDCB34272382@xxxxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-2022-jp";
reply-type=original
The first satellite, Sputnik-1
Launch of Sputnik-1, 4 Oct 1957
Satellite Catalog Number 1 is given in the rocket
Sputnik /Sputnik (A, SL-1) which launched Sputnik-1.
Satellite Catalog Number 2 is SPUTNIK-1 1957-001B
http://www.ne.jp/asahi/hamradio/je9pel/sputnik1.htm
JE9PEL, Mineo Wakita
------------------------------
_______________________________________________
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 7, Issue 326
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