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CX2SA > SATDIG 25.07.09 21:23l 358 Lines 11790 Bytes #999 (0) @ WW
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Today's Topics:
1. Re: FX614 (Chuck Hemker)
2. Re: FX614 (John Melton)
3. FUNcube a UK Linear Transponder Satellite (David Johnson)
4. Left /Right Hand polarization ... (John Papay)
5. Fwd: Hamsat article on the Make blog (Bruce Robertson)
6. Re: FUNcube a UK Linear Transponder Satellite (David - KG4ZLB)
----------------------------------------------------------------------
Message: 1
Date: Sat, 25 Jul 2009 02:56:46 -0400
From: Chuck Hemker <n2por@xxxxx.xxx>
Subject: [amsat-bb] Re: FX614
To: Andy Brian <briaandy@xxxxx.xxx>
Cc: AMSAT-BB <amsat-bb@xxxxx.xxx>
Message-ID: <20090725025646.54cb41ea.n2por@xxxxx.xxx>
Content-Type: text/plain; charset=US-ASCII
On Fri, 24 Jul 2009 13:50:35 +0200
Andy Brian <briaandy@xxxxx.xxx> wrote:
> HI,
>
> I'm looking for any simple source code in C-language for FX-614 (ax.25
> decoder) for undestanding simple ax.25 protocol.
I'm would also like to find a C implementation of the ax.25 protocol. The
only one I know of is in
linux kernel (in net/ax25). I'm not sure if that is that simple because it
may have too many kernel'isms in it.
But first some background info:
When dealing with 1200 baud ax25 things built on things:
ax.25
hdlc (takes the bits and makes it a package frame)
bell 202 (tones for the bits)
Now since the packets are sent over the air as sync and not async (the whole
packet is one continuous string of bits) you can't use the async clock
recovery stuff in the chip. Also because of this you can't use the transmit
and receive data pins on your standard async serial port.
Back in the DOS days, baycom came out with a modem similar to what your
talking about (and there were several clones using tcm3105 modem chip). It
worked by sampling one of the other leads on the serial port fast enough to do
clock recovery and hdlc decoding. (there were also ones that tied to the
parallel port)
(search for baycom and/or tcm3105)
You didn't mention what operating system your running on your pc.
Linux:
It looks like there are still baycom drivers in the linux kernel (source
drivers/net/hamradio, some docs somewhere in the Documentation directory)
Don't know what the status is.
(I haven't dealt with this, but I have done other ax25 things with linux in
the past)
dos: search the web
windows: I don't have a clue. I don't even know if it's possible without a
kernel level driver.
-
after you have the clock recovered, the hdlc frame decoded, and checksumed,
handing the packets off using kiss or 6pack or doing things using unconnected
packets either point to point or multicast like aprs or as a base of a pacsat
downlink protocol is just rearanging the bits.
full duplex transmit is just bit twiddling and then sending them out at the
right rate.
half duplex there are several timers to worry about so you don't collide with
other people.
ax.25 can get complicated with other things
have fun.
> I found only few
> asm code for PIC16, but c-lanugage is easily to adopt to other
microcontrollers.
> I tried to connect FX614 IC like in HITSAT
> http://www.hit.ac.jp/~satori/hitsat/img/decord.bmp and read at RX PC
> port with rs232 terminal programme,
> but I didn't receive any useful frame with b011111110 start (like
> describet in ). After this I found that all modem using pin CTS on
> RS232 port, I don't know how to handle this with
> PC to read directy with rs232 RXD port like HEX or binary values to
> see raw values of packet frames?
> It is possible to read values from FX614 (through max232 ) with PC to
> see raw format?
>
> So I'm looking for any simple source code in C to find how to decode
> signal from fx614 to microcontrollers port and then to PC
>
> Thanks for your help
>
> all the best Andy
> _______________________________________________
> 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: 2
Date: Sat, 25 Jul 2009 09:09:59 +0100
From: John Melton <John.Melton@xxx.xxx>
Subject: [amsat-bb] Re: FX614
To: Chuck Hemker <n2por@xxxxx.xxx>
Cc: AMSAT-BB <amsat-bb@xxxxx.xxx>
Message-ID: <4A6ABDD7.2060701@xxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Take a look at http://www.ka9q.net/code/ka9qnos/
Regards John g0orx/n6lyt
------------------------------
Message: 3
Date: Sat, 25 Jul 2009 12:14:40 +0100
From: David Johnson <david.johnson@xxxxxxxxxxx.xx.xx>
Subject: [amsat-bb] FUNcube a UK Linear Transponder Satellite
To: amsat-bb@xxxxx.xxx
Message-ID: <4A6AE920.1080103@xxxxxxxxxxx.xx.xx>
Content-Type: text/plain; charset=windows-1252
Hi,
AMSAT-UK has announced a new amateur satellite project ? FUNcube ? that
features a 435 to 145 MHz Linear Transponder for SSB/CW operation. The
project has received major initial funding from the Radio Communications
Foundation (RCF) and is expected be developed in collaboration with
ISIS-Innovative Solutions in Space BV.
FUNcube is an educational single cubesat project with the goal of
enthusing and educating young people about radio, space, physics and
electronics.
It will support the educational Science, Technology, Engineering, Maths
(STEM) initiatives and provide an additional resource for the GB4FUN
Mobile Communications Centre.
The target audience consists of primary and secondary school pupils and
FUNcube will feature a 145 MHz telemetry beacon that will provide a
strong signal for the pupils to receive.
It is planned to develop a simple receiver board that can be connected
to the USB port of a laptop to display telemetry in an interesting way.
The satellite will contain a materials science experiment, from which
the school students can receive telemetry data which they can compare to
the results they obtained from similar reference experiments in the
classroom.
FUNcube is the first cubesat designed to benefit this group and is
expected to be the first UK cubesat to reach space.
More details can be found at:
http://www.uk.amsat.org/content/view/696/68/
73
Dave, G4DPZ
AMSAT-UK 1267
AMSAT-NA LM-1260
------------------------------
Message: 4
Date: Sat, 25 Jul 2009 07:53:12 -0400
From: John Papay <john@xxxxxx.xxx>
Subject: [amsat-bb] Left /Right Hand polarization ...
To: amsat-bb@xxxxx.xxx
Message-ID: <200907251153.n6PBrRuX002604@xxxx.xxxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Myles,
AO51 435.300 is right hand circular polarization (RHCP).
AO51 435.150 is left hand (LHCP). If you try to hear
a LHCP signal with a RHCP antenna that is really right
hand, you will have a drop in signal that can exceed
20db. This will make the downlink unreadable at low
elevations. You definitely want to have switchable
polarization on UHF if at all possible.
The reason that people have a hard time hearing SO50
when they are using RHCP is that although the antennas
are supposed to be linear polarized, they don't fare
well on RHCP throughout the pass. I find that I have
to switch several times between right and left in order
to hear the bird throughout the pass. Before I had
switching, it was hit and miss with that bird.
The two meter side is not as important to switch unless
you plan to operate AO7 and VO52 which have downlinks on
2 meters. If you do operate those birds, you'll be able
to do much better if you can switch. Switching the uplink
on UHF on those birds sometimes makes a big difference too.
If you are serious about operating the birds, the investment
in polarity switching will be well worth it.
John K8YSE
------------------------------
Message: 5
Date: Sat, 25 Jul 2009 14:33:34 -0300
From: Bruce Robertson <ve9qrp@xxxxx.xxx>
Subject: [amsat-bb] Fwd: Hamsat article on the Make blog
To: AMSAT-BB <amsat-bb@xxxxx.xxx>
Message-ID:
<49657a760907251033l891e7b7n88dd9c30a99c02cf@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
If you haven't taken a look at this introductory article, you really
should. It does so many things well, in my opinion. First, it doesn't
assume the reader is (yet!) a ham. Second, it uses very simple tools,
like heavens-above.com, to ensure success. Finally, it has that
makergeek cred from the homebrew antenna setup. It would have been a
great intro for me when I was starting up.
73, Bruce
VE9QRP
On Thu, Jul 23, 2009 at 4:09 PM, Ollie Eisman<ollie@xxxxxxxxx.xxx> wrote:
> FYI
>
>
http://blog.makezine.com/archive/2009/07/catching_satellites_on_ham_radio.html
------------------------------
Message: 6
Date: Sat, 25 Jul 2009 14:59:47 -0400
From: David - KG4ZLB <kg4zlb@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Re: FUNcube a UK Linear Transponder Satellite
To: amsat-bb@xxxxx.xxx
Message-ID: <4A6B5623.50806@xxxxx.xxx>
Content-Type: text/plain; charset=windows-1252; format=flowed
/*"*//*It is anticipated FUNcube will be launched into a Sun Synchronous
Low Earth Orbit about 600-700km above the earth using one of the many
launch opportunities that exist for Cubesat missions."*/
*_Many_* launch opportunities ???
--
David
KG4ZLB
www.kg4zlb.com
David Johnson wrote:
> Hi,
>
> AMSAT-UK has announced a new amateur satellite project ? FUNcube ? that
> features a 435 to 145 MHz Linear Transponder for SSB/CW operation. The
> project has received major initial funding from the Radio Communications
> Foundation (RCF) and is expected be developed in collaboration with
> ISIS-Innovative Solutions in Space BV.
>
> FUNcube is an educational single cubesat project with the goal of
> enthusing and educating young people about radio, space, physics and
> electronics.
>
> It will support the educational Science, Technology, Engineering, Maths
> (STEM) initiatives and provide an additional resource for the GB4FUN
> Mobile Communications Centre.
>
> The target audience consists of primary and secondary school pupils and
> FUNcube will feature a 145 MHz telemetry beacon that will provide a
> strong signal for the pupils to receive.
>
> It is planned to develop a simple receiver board that can be connected
> to the USB port of a laptop to display telemetry in an interesting way.
>
> The satellite will contain a materials science experiment, from which
> the school students can receive telemetry data which they can compare to
> the results they obtained from similar reference experiments in the
> classroom.
>
> FUNcube is the first cubesat designed to benefit this group and is
> expected to be the first UK cubesat to reach space.
>
> More details can be found at:
>
> http://www.uk.amsat.org/content/view/696/68/
>
> 73
> Dave, G4DPZ
> AMSAT-UK 1267
> AMSAT-NA LM-1260
> _______________________________________________
> 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
>
>
--
David
KG4ZLB
www.kg4zlb.com
------------------------------
_______________________________________________
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 4, Issue 357
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