Portable Satellite Station With Additions For Digital and Packet
We’ve recently upgraded our Portable Satellite Station 2.0 to add digital and packet capabilities. The upgrade was pretty simple – we added a SignaLink USB Soundcard and a Windows Laptop PC. Most of the software for packet and digital Amateur Radio communications is written for the Windows OS so using a separate laptop running Windows 10 was the simplest way to go. Another benefit of the second laptop was added screen space to use when doing packet communications via satellites and the International Space Station (ISS).
The video above was made during the reception of an SSTV image from the ISS during a pass over the United States. The video gives a good idea of what its like to receive SSTV from the space station.
Another SSTV Image From The ISS
We were able to receive several different images from the ISS during the period that it was transmitting SSTV worldwide.
A Third SSTV Image From The ISS
It was pretty easy to capture the SSTV transmissions from the ISS with our Portable Satellite Station 2.0 setup. The signals were strong and I would imagine that the SSTV transmission could have also been received with a simple portable satellite setup with a hand-held yagi antenna.
We hope that the ISS will send SSTV images again in the near future. It was fun receiving them.
The new antennas will require some modifications to our portable antenna system arrangement. They will need to be mounted on a cross-boom near their centers. As a result, a non-conductive fiberglass cross boom will be required to avoid problems with pattern distortion.
FGCB60 Non-Conductive Cross Boom
We will be using an M2 Antenna Systems FGCB60 Cross Boom which has removable, non-conductive end sections made from fiberglass material. The removable ends will make it easier to transport the antenna system. We will also need to make a new mast which is 24″ longer than our current one in the 2.0 Station to create the needed ground clearance for the longer antennas.
Alfa Spid Az-El Rotator
We are also planning to use a larger Alfa Spid Az-El Rotator. This unit will handle the extra weight of the longer yagi antennas and cross boom assembly and is more precise than the Yaesu unit used on the 2.0 station.
We have a DXEngineering EC-4 Control Box from a previous project and we can use it to control the relays in the Polarity Switches which will be part of the 3.0 Station antennas. The box will allow us to select any combination of left and right-hand circular polarization on the 3.0 Station uplink and downlink antennas.
We should have all of the parts here for the 3.0 upgrade by the end of the year. We’ll post more as the project proceeds. Other articles in the Portable Satellite Station series include:
Assembly of the case and the hardware was straightforward. The folks at Adafruit provide a pre-built Jesse Linux image for the RPi which includes the necessary driver for the Touch Screen Display.
After a bit of configuration work and the creation of a few shell scripts to make it easy to boot the RPi to an HDMI display or to the Touch Display, we were ready to install the GH Tracker App. we also enabled the VNC Server on the RPi so that we could use a VNC Client application on our MacBook Air in place of directly connecting a display, keyboard, and mouse to the RPi. Finally, we installed Samba on our RPi to allow files to be moved between our other computers and the RPi.
GHTracker Running on the Raspberry Pi
Jeff at Green Heron Engineering provided a copy of GHTracker V1.24 and the necessary serial interface library to enable its use on the RPi. Jeff is planning to make a tar file available with GH Tracker and the library in the near future. We did some configuration work on LXDE (the GUI interface for Linux that runs on the RPi) automatically run GH Tracker whenever the RPi is booted up. We also optimized the GUI for the sole purpose of running GH Tracker on the Touch Screen Display. Finally, we configured the Ethernet and WiFi interfaces on the RPi to work with our home network and with our LTE Hotspot modem.
RPi GHTracker Test Setup
With all of the software work done, it was time to test the combination with our Satellite Rotator System. The setup worked on the first try using a WiFi network connection between the MacBook Air Laptop running MacDoppler and the RPi. The USB-based serial ports which control Azimuth and Elevation direction of the rotators worked as soon as they were plugged into the RPi. Also, the touchscreen interface works well with the GH Tracker App making the combination easy to use.
MacDoppler and GHTracker via VNC
The VNC Client/Server combination allows us to work with the software on the RPi right form our MacBook Air laptop. It also makes for a nice display for monitoring the GHTracker App’s operation from the Mac.
Thanks to the help from Jeff at Green Heron Engineering, this project was very easy to do and worked out well. The Raspberry Pi 3 platform is very powerful and relatively easy to work with. It makes a great start for many Ham Radio projects. Also, there is a wealth of online documentation, how-to information, and open source software for the RPi. I hope that some of our readers will give the RPi a try!
Another new radio from Icom based on their SDR platform. This looks like a great radio for Satellite and EME use. We’re going put in a pre-order for this radio and will plan to include it in our Portable Satellite Station. I’ll post more here as details become available.
John Keslo, W1MBG, Jamey Finchum, KC1ENX, and I (all members of the Nashua Area Radio Club) recently had the chance to again visit the Academy for Science and Design (ASD) in Nashua, New Hampshire to provide an Introduction to Amateur Radio for the students there. ASD’s goal is to be a world-class school that specializes in science, engineering, mathematics and design for students in grades 6-12.
ASD periodically holds SPARK (Symposium Promoting Advancement of Real-world Knowledge) conferences, which enable ASD students to learn about areas which might help them to develop careers in Science, Technology, Engineering and/or Math (STEM).
The students at ASD are extremely bright and are highly motivated to develop STEM careers. We had about 65 students elect to attend the two sessions that we presented and the kids showed a lot of interested in our presentations.
We also put together an HF GOTA station in the lobby of the school. This gave the kids a chance to get on the air and experience Amateur Radio first hand. After the kids got over the usual “mic-fright”, they had a lot of fun.
We are looking forward to our next opportunity to participate in ASD’s SPARK Day in the fall. This is one of the most enjoyable events of the year for me.
The idea was to use an IC-7300 to create a 100W station and use a Solar/Battery combination to power the setup. Solar/Battery made us “legal” as a SOTA activation. We combined two 90W solar panels which I had with a MPPT solar charing system and two LiPo batteries to create the power system for the activation.
All of this gear was carried to the site and setup in about an hour. A 25 ft. section of LMR-400UF coax completed the station. The mast was guy’ed with rings which allowed us to turn the mast/antenna combination to point the Yagi in any direction.
Anita, AB1QB and Curtis, N1CMD Operating in the June VHF Contest
Between the SOTA/POTA activation and the June VHF contest, we made a little over 130 contacts on 6m. We did not have any real Es openings so most of our contacts were regional. Having the elevation provided by being on Pack Monadnock made us quite loud for the stations that could hear us. Several of our club members got on 6M and joined the fun. We did have a brief Es opening and managed to work a station in Alabama and one in Florida.
Mike, AB1YK Portable 6M
Mike, AB1YK has a much more portable 6M setup and used lower power to have some fun on 6M as well.
Al, KC1FOZ and Tom, KC1GGP Operating Portable
Al, KC1FOZ and Tom, KC1GGP put together a nice station and operated using battery power. Several other club members came out with portable station or to watch and have fun as well.
Our first SOTA/POTA activation was a lot of fun and Anita and I are looking forward to the next one!
We recently did a Tech Night at our club on Building and Operating a Satellite Ground Station. As part of my portion of our Tech Night presentation, I recorded several LEO satellite contacts and made videos showing the operation of the computer controlling our Satellite Station 2.0 during these contacts. These videos give an idea of what its like to operate through LEO satellites.
The heart of any GoKit is the Transceiver. We’ve been using Kenwood equipment for our APRS iGate for some time now and we have had good results with it. Kenwood’s latest 50W transceiver with APRS is the TM-D710GA. This unit provides full support for APRS tactical applications and now includes a built-in GPS receiver making it ideal for our GoKit application.
We had a chance to look at the iPortable enclosure at Dayton and decided that their Pro 2 4U deep unit would be a good choice for our GoKit application. The iPortable enclosures are based on a portable rack mount case and include a DC power system, speaker and headphone hookups, a light, and provisions for a cooling fan.
With all the components in hand, we began the construction of our GoKit. Reliability is important in any portable system like this so we put some time into securely mounting all of the equipment and neatly arranging the cabling. First came the shelf which holds the Kenwood transceiver and a SignaLink USB sound card. A combination of drilling the shelf to secure gear with large cable ties and #8 stainless hardware was used here.
Coax Connector Cables
Our iPortable case was equipped with both SO-239 and N-connectors on the front panel to allow for antennas and feed lines equipped for either connector type. To make the change over between the connector types easy, we installed separate PL-259 jumper cables for each connector. One simply connects the appropriate jumper to the radio.
Display and Power Shelf
The power and AvMap display shelf was next. The AvMap display mount was dissembled and modified to accept a custom mounting bracket.
PWRgate Battery Interface and Charger
The iPortable enclosure was drilled to mount a West Mountain Radio PWRgate to handle backup battery charing and management. The PWRgate supports instantaneous switching between an AC power supply and a backup battery and can accommodate a wide range of battery types and sizes.
The last piece of the setup was the antenna. We wanted something that was portable, easy to set up and would provide good performance. We choose a Diamond X-30A 2m/70cm ground plane antenna and mounted it on an 12′ fiberglass push up mast. The feed line is made from 25′ of LMR-400UF coax. Several bungee cords are used to attach the mast to a fence post or other vertical structure.
The picture above shows the completed GoKit in operation. We typically set one side of the Kenwood TM-D710GA to operate as an APRS transceiver and Digipeater and the other side to operate on a local repeater or simplex FM. The SignaLink sound card is used with a laptop computer running Fldigi and NBEMS for messaging applications. The iPortable case has a 13.8V lighter socket which connects to a power brick to power our laptop PC.
GoKit Packaged for Transport
The GoKit is quite portable when closed. All of the equipment and cable connections are enclosed and protected by the case’s removable end caps. We’ve tested our GoKit during our club’s weekly repeater net and it worked great. The first real use of our new GoKit will be at Field Day this year. It will be located in our public information tent and will be used as a “talk-in” system.
Dave Merchant K1DLM, our Field Day chairman, is bringing some 21st Century radio and computer technology to our Field Day setup this year. There are several aspects to this new component of our Field Day plans including –
An on-site WiFi Network to enable using the N1MM+ Logger in network mode for sharing of log information, station activity, real-time scores, and messages
A central Score Board and Field Day Information Computer in our public information tent
2017 Field Day Site – Upper Field Layout
We will again be holding our 2017 Field Day operation at the Hollis-Brookline High School in Hollis, NH. We are planning on using the upper baseball field area as our main operating location. We have decided to add a third tower this year and locate it on a soccer practice field which is situated several hundred feet away from our main operating area. All of our antennas and equipment will lie within the required 1000′ circle but the third tower would situate those operating at that location away from the rest of our group. Dave’s solution to this problem was to set up a network and operate two Software Defined Radios (SDRs) at the lower site remotely from our location on the upper field.
Dave has enlisted Piece Fortin, K1FOP to be our IT Chairman for Field Day this year. Pierce has been instrumental, along with Dave, in the planning and testing of all of this new technology. Pierce and Dave have a great deal of networking and IT experience and knowledge and we could not have put together what is described here without them.
Dave K1DLM, Piece, Hamilton K1HMS, Mike Ryan K1WVO, Anita AB1QB, and I have gotten together multiple times to set up and test all of this new technology. I wanted to share some more about the equipment and the associated testing (which has been staged in the kitchen at our QTH – thank you, Anita!).
We began the testing process by setting up our 20m CW station.
20m CW Station Test
This station uses an Elecraft K3S Transceiver, a K1EL WinKeyer and the N1MM+ Logger running on a Windows 10 Laptop PC. We used this station to get our basic N1MM+ setup including our Field Day CW keying macros right.
40m SSB Station Test
Next came our 40m SSB station. This setup uses an Icom IC-7300 Transceiver and allowed us to set up and test N1MM+ on the fly audio macro recording and playback. All three of our SSB stations will have on the flyrecording and playback capability which will allow each of our SSB operators to record and use a custom set of audio macros.
Digital Station Test
Next came our Digital Station. This station uses one of the two remote Flex-6700 SDRs.
Remote Flex-6700 SDRs and Antenna Switch
Dave, K1DLM put together a really nice package for the two Flex-6700 SDRs and associated equipment which will be located on the lower field. He used a rack system to mount the two SDRs, power supplies, a three-band Tri-plexor, a set of bandpass filters for 80m, 40m, 20m, 15m, and 10m and a 403A 8×2 networked antenna switch. This setup allows either of the two SDRs to share the tri-band yagi or the 40m and 80m Inverted-V antennas on the tower on the lower field and operate on any of the 5 available HF bands. Antenna and filter switching automatically track the frequencies of the two SDRs making the setup simple to use.
Digital Station Second Display – SmartSDR & More N1MM+
The Digital Station’s remote SDR will be operated using a SmartSDR client running on the Digital Station laptop PC. This station will have a second monitor to better accommodate all of the windows associated with it.
Digital Station Main Display – N1MM+
The main display associated with the Digital Station will run decoders for all PSK and RTTY modes. The ability to decode multiple PSK signals simultaneously and multiple RTTY decodes are available. The Digital station also acts as the N1MM+ master station in our Field Day setup for all of the other stations which use N1MM+.
Satellite Station Test
Our Satellite Station 2.0 was also added to the test setup. It uses a MacBook Air laptop running MacDoppler to control the antenna rotators and the Icom IC-9100 Transceiver which are part of our Satellite Station. A Windows 10 Surface Pro computer is included which runs N1MM+ and provides logging and other network functionality for our Satellite Station.
GOTA Station Test
We also tested our GOTA station which uses the second Flex-6700 SDR and a FlexRadio Maestro to provide a more conventional “buttons and knobs” interface for our GOTA operators to use. This station will also have a laptop PC running N1MM+ for logging.
We also build and tested a Scoreboard PC. This computer will be located in the Public Information tent at Field Day and will be connected to a large display. It will show our real-time score, QSOs being logged as they are made and other useful information about our Field Day operations. This computer will also continuously play videos from our Video Collection and will provide access to IP video cameras which monitor the tower and equipment on the lower field.
Pierce, K1FOP and Hamilton, K1HMS Testing CW Stations
Our networked N1MM+ testbed contained at least one station of each type (CW, SSB, Digital, Satellite, and GOTA) that will be part of our Field Day setup this year. The Station Masters for the additional CW and SSB stations came by to test their setups using the test bed.
Field Day Networking System
The networking system which Dave and Pierce built is central to all of the technology described here. All of the gear is mounted in a single rack which will be located on the upper field during Field Day. The setup includes a Firewall/DHCP server, a commercial grade outdoor WiFi access point, a 4G LTE modem for Internet access, an Ethernet Switch, and a UPS power supply.
MoCA Data Link Cable
The upper and lower fields at our Field Day site are separated by several hundred feet. A thick line of trees between the two locations raised concerns about connecting the upper and lower sites using WiFi. Pierce came up with a great solution to this problem – we will be using MoCA Data Modems and RG6 Quad Shield 75 ohm Coax Cable to provide a 10 Mbps data link between the two sites. We tested the MoCA link using a much longer run of coax cable then we will need to use at Field Day and confirmed full 10 Mbps throughput.
N1MM+ Talk Window
Our networked N1MM+ setup will allow any station in our setup to send messages to everyone who is operating at Field Day. We can use this capability for important communications like “lunch is ready!” or “I need help from Pierce (our IT chairman) on the 40m SSB station”, or “The 6m band is wide open!”.
Our GOTA and Digital stations will be located together in the same tent and will provide our Field Day 2017 visitors to see and use 21st-century Amateur Radio technology to make contacts. We are expecting young people who participated in our High-Altitude Balloon project and from other local schools where we have done Amateur Radio activities to attend. In additional to being a learning opportunity for all of us in the Nashua Area Radio Society, we hope that the state of the art technology that we are using will generate interest among our visitors. If you are local to the Nashua, NH USA area, come pay us a visit during 2017 Field Day. We’d enjoy providing a tour for you and your family along with a chance to Get On The Air. Hope to see you at Field Day!