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. Putting together a station and the necessary software to use Greencube is not difficult. If you already have a computer-controlled satellite ground station that works on 70cm, you may already have most of what is needed. We’ll cover Greencube (IO-117) setup in detail in this article.
Operating with Greencube – What’s Required
Greencube (IO-117) requires the following for successful contacts via its digipeater:
- A directional antenna with at least 12 dBi gain
- A 70cm SSB/FM capable Transceiver with a soundcard interface and at least 25 watts of output at the antenna
- Software to control the Transceiver to correct for Doppler shift and provide antenna tracking control or pointing information
- A computer running modem software and a Greencube Terminal Program
- A low-noise preamp at the antenna is recommended
Greencube Satellite Antennas
We have three different antenna combinations that are Greencube capable here:
- An M2 Antenna Systems 436CP46UG antenna(18.9 dBic gain) on a house-bracketed tower
- An M2 Antenna System LEO Pack with a 436CP16 antenna (13.3 dBic gain) on a transportable ground tower
- An M2 Antenna Systems 440-11X antenna (13.44 dBi gain) mounted on a camera tripod for portable use
All three antennas have Advanced Receiver Research Low-Noise preamps which are powered via the associated antenna’s coax feedline. Unfortunately, the ARR preamps are no longer available. A good alternative would be the SSB Electronic SP 70 preamp. I recommend choosing a preamp that can be sequenced using coax power from your transceiver if your transceiver supports coax-powered preamps. This approach ensures that your preamps are protected from transmit power in most operational scenarios.
Radio, Computers, and Power
All of our Greencube (IO-117) setups use an Icom IC-9700 Transceiver.
We use two computers to run our stations:
- A Mac (iMac or MacbookAir) running MacDoppler to control antenna tracking and to control our IC-9700 to perform Doppler correction
- A Windows PC running the modem, terminal client software, and a logger for using Greencube’s digipeater and for decoding telemetry
Using the two computers means that both must simultaneously control the IC-9700 via the radio’s CAT interface. This is easily accomplished with the IC-9700 by using both the CI-V and USB CAT interfaces. The radio’s CI-V interface is used with MacDoppler, and the USB interface is used with the Windows PC to connect the IC-9700’s Rx and Tx audio to the modem SW and to provide for PTT via a COM port.
We use AC power for our fixed and transportable setups.
Our portable setup uses solar power consisting of two 90-watt foldable panels, an MPPT charger system, and a pair of A123 LiPo batteries. We’ll share more about our portable and transportable setups in subsequent posts.
We use the following software for our Greencube (IO-117) ground station:
- UZ7HO’s Greencube Soundmodem (download greentnc.zip)
- OZ9AAR’s Greencube Terminal Software
- DK3WN’s Greencube Telemetry Decoder
- MacDoppler to control antenna tracking and Doppler correction on the IC-9700
- N3FJP’s ACLog for logging contacts
MacDoppler runs on a Mac computer (iMac or Macbook Air), and the rest of the software runs on a Windows PC.
The links above include instructions for setting up each of the software applications. The following are some notes on Greencube (IO-117) setup for each software component.
The Greencube (IO-117) setup in MacDoppler configures the IC-9700 Transceiver to operate in simplex SSB digital mode. This is the SSB-D choice in MacDoppler’s Modes tab for Greencube.
You’ll want to select SSB-D mode in MacDoppler to track Greencube and configure the IC-9700 to work with the Greencube digipeater. Setting the uplink and downlink offsets to -1.200 KHz will place Greencube’s packet transmissions in the middle of the IC-9700’s passband.
There is a specific version of UZ7HO’s Soundmodem for use with Greencube (see the link above to download greentnc.zip). The soundcard and PTT COM port interfaces provided via the USB connection to the IC-9700 must be configured in Soundmodem.
Soundmodem Devices Settings
The USB connection from the IC-9700 to a Windows PC will create a pair of sound devices (in this example, USB Audio CODEC) and a COM port (in this example, COM15) for CAT and PTT control. These must be properly configured in the Settings – Devices choice on the Soundmodem main menu.
Soundmodem Modem Settings
The Settings – Modems choice on the Soundmodem main menu brings up this dialog. The settings are the default ones. Note that Soundmodem has two modes – GreenCube 1200bd and GreenCube 300bd. The GreenCube 1200bd setting is normally used for digipeater operation, including decoding telemetry when enabled. You’ll need to use the GreenCube 300bd setting to decode telemetry if Greencube’s digipeater is turned off.
IC-9700 Transceiver Settings
There are some important adjustments to the configuration of the IC-9700 that need to be made for Soundmodem to work properly with the transceiver.
Configuring the CI-V USB Port to Unlink from [REMOTE] is necessary to allow it to function independently for the other interfaces.
You’ll want to set the AF Output Level of the USB interface to about 25% of the maximum and adjust the Windows audio control in Control Panel to get a display on the Soundmodem waterfall of about the intensity shown above.
Setting up the Tx audio levels is important to avoid overdriving the Transmitter. A good place to start is to set the USB Mod Level in the IC-9700 to about 25%.
Then adjust the Windows audio control in Control Panel to get full transmitter output power with only one or two bars of ALC indication on the IC-9700’s ALC meter when transmitting via the Greencube Terminal client. This adjustment is an essential part of your Greencube (IO-117) setup.
OZ9ARR’s Greencube Terminal Setup
A client program is required to format and decode the packets from Greencube. We are using OZ9ARR’s Greencube Terminal for this purpose. This program includes a macro button capability to help you format Greencube Tx packets and includes some nice capabilities for logging contacts and identifying new DXCCs, Grids, and Stations that you have not yet worked.
We are using Greencube Terminal with N3FJP’s ACLog to log contacts made with Greencube. This makes it easy to export our contacts to an adif file after each Greencube operating session and import them into our main logger. We also periodically export an adif file containing all of our satellite contacts from our main logger and provide access to this file so Greencube Terminal can determine what we’ve worked before. OZ9ARR’s Greencube Terminal webpage thoroughly explains how to set up and use the program.
DK3WN’s Greencube Telemetry Decoder
Greencube periodically sends Telemetry information. You can decode it by using DK3WN’s Greencube Telemetry Decoder with Soundmodem. You can download the decoder and see how to install it on DK3WN’s webpage.
Making Contacts with Greencube
With your Greencube (IO-117) Setup complete, you should be ready to make some contacts! Begin by starting up all of the software and configuring MacDoppler to track Greencube in SSB-D mode. When Greencube is in range, you should see Greencube’s packet transmission being displayed in Soundmodem’s waterfall, and you should be able to hear the packet bursts on your Transceiver. Adjust the Soundmodem decode pointers by dragging them with your mouse to center them in the waterfall traces received in Soundmodem. The setting should be around 1400 – 1500 Hz. Also, make sure that GreenCube 1200db mode is selected in Soundmodem. You should see packets being decoded by Soundmodem.
You can configure the Shortcut buttons to handle the steps needed to make a contact. The images above show the setup of the buttons that we are using here.
You’ll want to set the Tx delay for 0 – 2 seconds to give your preamp time to recover from transmitting before you receive your digipeater packets back from Greencube.
You can begin to make a contact by either clicking on another station’s CQ to load the station’s callsign or by just calling CQ yourself. Next, use the INFO button to send your callsign and grid square and then the RRR and 73 buttons to complete your contact. When you are done, you can right-click on the last packet in the exchange or on the station’s callsign that you have worked in one of the right windows to log the contact. That’s all there is to it!
Note that you’ll want to confirm that Greencube has heard and digipeated each of your transmissions. Collisions, fading, and other effects will often cause your packets to not be digipeated, and you’ll need to repeat your transmission until it is digipeated by Greencube.
You can also use the digipeater in store-and-forward mode by setting a long TX Delay (the number is in seconds). This can be as long as several hours to allow you to have Greencube digipeat your packet on the other side of the world! Note that store and forward contacts do not count for operating awards such as Worked All States, VUCC, or DXCC.
The video above shows Uz7HO Soundmodem and OZ9AAR’s Greencube Terminal being used to make contacts during a Greencube pass. the video also demonstrates some of Greencube Terminal’s features for identifying unworked calls and grids. You’ll want to spend some time reading OZ9AAR’s webpage to learn about and take maximum advantage of the many features Greencube Terminal can provide.
More Fun With Greencube
This article is the second in a series that we are working on. You view the other articles via the links below. This is a work in progress, and we’ll be creating additional Greencube-related posts in the near future:
- Greencube (IO-117) – A New Satellite for DX!
- Greencube (IO-117) – Completing a Satellite Worked All States
- Greencube (IO-117) – M2 Antenna Systems LEO Pack – Will It Work?
- Greencube (IO-117) – A Portable Station for Activating Grid Squares
- Greencube (IO-117) – The Road to a Satellite DXCC?
You can also read more about our Satellite Ground stations here.