Amateur radio station capable to decode signals from CubeSat satellites?

[armadillo]

Ground station capable to receive and decode signals from CubeSat satellites?

I want to buy/build a ground station (antenna + receivers + computer + etc.) capable to receive and decode some data sent by a CubeSat 1 kg, 1 cubic decimeter mini satellite which circles the Earth in a 500 km polar orbit.

I know that the satellite emits a 436.8375 MHz (100 mW, Continuous Wave) beacon and a 437.470 MHz (350 mW, 1200 bps AFSK AX.25) data signal (see 1 and 2)

1) Examples of cubesats:
http://cubesat.ifastnet.com/forum/vi...c.php?f=5&t=16
2) Communication protocol AX.25:
http://cubesat.ifastnet.com/forum/vi...c.php?f=5&t=20

Question: What kind of equipment do I have to buy in order to receive the beacon (which tells me the CubeSat is present above the horizon) and also receive and decode the data sent at 1200 bps?

[5B4AJB]

Have a look at the Orbitron homepage, it's very capable (and free) tracking software.
Have a look at the WinPack and AGW homepage, again very capable (and free) packet decoder.

As for the hardware you're going to need, maybe a couple of phased beams for 70cm?
A receiver, of course, a masthead premplifier maybe, probably most importantly, some nice coax.

Polar orbit? they're usually quite far up (500km?) and harder to copy, might need some fairly "big" beams for 100mW on 70cm...

[armadillo]

Thank you for your answer. I will take a look at those too programs and also I will see where I can buy that 70 cm antenna from or how could I build it.
I got a bit scared when searching the internet in order to buy the equipment you described I found prices over 20 000 $, for an satellite entire ground station working in the 70 cm band.
In my case a 1500 $ would be a maximum I could spend for the antenna, receiver, and the other components.

[pa3weg]

Will you need to track the cubesat continuously (every pass)?

If you want to use it as ham radio operator (license required) I would suggest you to buy a radio like the Kenwood TH-D7 with built-in TNC and an arrow antenna and operate outside. Its great fun! You can also uplink if you are a licensed radio amateur.
If you just want to receive it for your personal interest without transmitting, getting a radio receiver (handheld) and outputting the audio into the soundcard is an even cheaper option.

Off course if you want to do tracking and uplinking for an university team or from your own chair inside, investing in good equipment is well worth the money.

If you are setting up a university or corporate ground station you might want to buy a complete solution witch is supported and saves you lots of time.

[armadillo]

At least in the near future, I do not intend to uplink. Only people who built the picosat are able to send intelligible commands for their CubeSat.
I am not a licensed radio amateur and I do not have special interests in this hobby. I just want to listen, more precisely to receive the AX.25 packets and the call sign of some cubesats, even if I would not be able (most likely) to decode the data. Also I want to receive the beacon and listen to it as the satellites pass overhead.

You say that I need license for Kenwood TH-D7. What type of receiver will allow me to just listen without license and output the signal in a sound card. Is it legally possible?

For the 436.8375 MHz CW signal I suppose the receiver multiplies that high frequency with another high frequency in order to translate it in the range of audio frequencies so I will hear a continuous sound in the loudspeakers, maybe with a slight change in frequency to account for the Doppler shift.

However, I am not sure if the same procedure could be applied to translate the 1200 bps, AX.25, AFSK 437.470 MHz data signal. A sound card can sample at 44 KHz so theoretically it can sample well a 1200 Hz square signal. I will make something like a Software Defined Radio.

I still need more information about a cheap and in the same time workable antenna and an amplifier - receiver that can convert the 436, 437 MHz signals in 0 - 20 KHz audio frequency range, in order to process the information using the sound card and my computer.

[5B4AJB]

Receiving/decoding the AX25 packets can be done with a cheap scanner & soundcard.

Tuning the beacon will require a much more expensive (multimode) receiver.

You only need a license if you transmit, just owning a transmitter is OK.

[armadillo]

Does anybody try this Beacon Decoder Software for Cubesats?
I do not know how to start it and what exactly it can do.

[5B4AJB]

Just had a quick look at the PDF help file.

some (most) satellites output data, like battery Voltage, current drain, solar cell Voltage, sub-mode status etc etc with a continuous beacon.

In this case it seems to be a (compressed) Hexadecimal value transmitted by AX25.

The XML in the link you gave has to be edited according to this (specific satellite) data, you'll need to know what format its output is before you can start working out the XML code.

Sorry if it seems a bit complicated so far, basically, the XML chops up the HEX string, applies a formula to some or all of the data, then displays it with units (5.5V for example).