Greencube (IO-117) is a Medium Earth Orbit (MEO) satellite that carries a 70cm digipeater. This satellite can provide DX contacts covering a wide area around an Amateur Radio satellite ground station.
Making contacts through Greencube is not terribly difficult but it requires a lot of equipment as well as a bunch of software.
Equipment you need a .70 cm SSB radio capable of computer control. I’ll be using my Yaesu FT-847 which was made to work satellites.
You will need a fairly high gain .70 cm antenna and preamp. I will be using a Gulf Alpha 8×8 satellite antenna and a RF sensed ARR preamp. These will be mounted on a top section of Rohn 25 tower. A Yaesu 800-DXA rotor will be used for azimuth and a G-500A rotor for elevation. These rotors are computer controlled with ERC rotor cards. Feed will be 1 inch hardline. The FT-847 can provide power via the coax for the preamp but I will need to add a bias tee at the tower to pull out the 12V before it gets to the antenna. The problem is I have not been able to locate a bias tee that can handle more that 50W. Though that may not be an issue as the ARR SP432VDG can only switch 25W of power. For this project I will probably just run power separately for now. I’ll probably end up having to add a sequencer, rf relays and put in a P432VDG preamp instead, but that’s a problem for down the road.
Greencube requires special software to decode and transmit. Unfortunately this software is only available for Windows. So I am running Win 10 Pro in VirtualBox. The first program you need is UZ7HO’s Greencube Soundmodem (download greentnc.zip). You need this specific version of UZ7HO’s Soundmodem for use with Greencube. I’ll be using a usb sound card and an EZ-Link interface to connect to the FT-847 which I will configure in Soundmodem.
A client program is required to format and decode the packets from Greencube. We are using OZ3ARR’s Greencube Terminal for this purpose though there are other programs available. Greencube Terminal seems to have the most options as it hooks with a number of logging programs, has pre-programable macros and interfaces directly to Greencube Soundmodem.
On the Mac side I’m running MacDoppler which controls the FT-847 via the serial port and the rotors via the ERC interface. Mac Doppler will track the satellite and when in view will point the antennas at it as well as do doppler correction to the radios frequency. I also have an IF tap in the FT-847 which allows me to run a SDR receiver so I can monitor the reception. This is very handy when trying to find your uplink/downlink frequencies. I will also be logging the contacts with RUMlog as well as a local AIDF file.
I’ll be putting the station on the air in the next couple of days and will report back how it goes.
Update 1
Tower is about ready and hope to install the mast, rotor and antenna tomorrow. In the meantime I’ve been messing around in the shack. Was on the International Space Station a few times with packet. Learned that the IF tap/SDR combo is really neat. Using SDR Angel I was decoding packets from the 847’s IF of 45.705. I also decoded them on the Windows side using Soundmodem. Using UZ7HO’s terminal program I also sent some packets up to the space station. Can’t wait to get the full station up and running. More to come…