After our contact, I decided to become an ARISS Mentor so I could help other schools make contacts with astronauts aboard the ISS. I spent the last year working with Dave Jordan, AA4KN to learn how the ARISS program works and how to help schools make successful ISS contacts. Dave did a great job coaching me as I worked with Council Rock H.S. South in Holland, PA to prepare for their ISS Contact…
I recently had the privilege of helping Council Rock H.S. South in Holland, PA to make contact with astronaut Drew Morgan on the ISS. The link above shares the story of this amazing experience and my journey to become an ARISS Mentor. The article also contains videos and photos that capture and share the experience. I hope that you enjoy it!
Students at Council Rock High School South in Southampton, PA will be talking with Astronaut Drew Morgan, KI5AAA aboard the ISS on Thursday. The ISS will be over our area here in the Northeastern Unit States beginning at about 12:55 pm eastern time on Thursday, December 5th. Council Rock’s ARISS Contact is made possible by the ARISS Program…
You should be able to hear Drew on the ISS voice downlink at 145.800 MHz FM. The ISS pass will be a high one over our area. As a result, we should be able to hear the downlink using a good vertical antenna and perhaps even using an HT.
I am serving as the ARRIS Mentor for Council Rock H.S. South’s ISS Contact. I am looking forward to the opportunity to be at their school on Thursday to be part of what I am sure will be a very memorable event.
We continued to test our Portable Satellite Station 4.0 as part of AMSAT’s 50th Anniversary Celebration WAS Activations. You can read about the activations and our station’s performance via the link above. Overall, we were pleased with how the portable setup performed. The weakest link was the downlink performance of our antenna system. We are working on some ideas to improve this element of our setup – more to come on this project…
We have created a program that we call Ham Bootcamp. Bootcamp to helps recently licensed and upgraded hams to get on the air. We are making this program available to up to 100 HamXpostion attendees on a first-come-first-served basis.
Our Bootcamp program will run from 9 am to noon on Saturday, September 7th in the Federal Room. Bootcamp will feature tracks for both Technician and General class license holders. It is also a great place for folks who are not yet licensed to learn more about Amateur Radio and how to get on the air.
Our Bootcamp program will include:
How to make a contact and join a repeater net
Putting together an HF station
Radio, antenna, and feed line choices
Getting started with FT8 and digital modes
Exchanging QSL cards
Learning Morse code
Tips on upgrading
Introduction to ham radio kit building
Handheld radio programming tutorials
Ham Bootcamp is free. Participants will receive discount certificates for a kit build at the show and for purchase of Ham Radio Gear from Ham Radio Outlet.
I wanted to share our plans for several hands-on activities at HamXposition @ Boxboro in September. We hope that Ham Bootcamp will be of particular interest to folks getting into Amateur Radio. You can learn more about Ham Bootcamp and all of our planned activities via the link above. We hope to see some of our readers at HamXpostion next month!
The Nashua Area Radio Society always brings something new to each Field Day that we do. In addition to our Computer Controlled Satellite Station, we will be adding a state of the art Weak Signal Antenna System and Station to our Field Day 2019 lineup. Our VHF Station will use a dedicated 40 ft Tower with Tower Mounted Preamps and low-loss feedlines. You can see what is going on at Field Day 2019 on 6m and above via the preceding link.
Frequency accuracy and stability become more challenging for transceivers that operate at 400 Mhz and above. Our 4.0 Satellite Stations operate at frequencies approaching 1.3 GHz and we want to be sure that their operating frequencies are accurate and stable. Our Flex-6700 SDR includes a GPS Disciplined Oscillator (GPSDO) so the radio and all of the transverters associated with the radio use the radio’s GPS disciplined 10 MHz output for frequency synchronization.
We choose a GPSDO from Leo Bodnar. The unit is compact, USB powered, and comes in a nice case which includes a GPS antenna and a USB cable. The unit has two GPS disciplined frequency outputs which can be configured for a wide range of frequencies and levels via a Windows application.
GPSDO Connected to an IC-9700
The GPSDO is connected to the 10 MHz reference input on the back of the IC-9700 with a BNC to SMA cable and the GPSDO is powered via a USB connection to our iMac. We configured the GPSDO output frequency to 10 Mhz and for an output level of +7.7dBm (drive setting 8mA). We also added a 20 dB pad in line with the GPSDO output to better match the drive level requirements of the IC-9700’s 10 MHz input.
The GPSDO will lock in a very short period of time (less than 1 minute) once GPS antenna and power connections are made the unite t. The unit has a red LED on each of its outputs and the unit is GPS locked when the LEDs are on and not flashing.
Configured and 10 MHz Input Locked IC-9700
The last step in the setup process is to configure the IC-9700 to sync its reference frequency to the 10 MHz input. This is easily done in the IC-9700’s Set/Function Menu.
It was pretty easy to add GPSDO locking to the IC-9700 and the arrangement described here works well. While this upgrade is not essential for satellite operation, it’s nice to know that our satellite transceiver frequencies are accurate and stable.
You can find other articles about our Satellite Station 4.0 project here:
The IC-9700 is based upon Icom’s direct sampling SDR platform. It supports all modes of operation on the 2m, 70cm, and 23 cm bands. The radio also supports satellite modes and D-STAR.
MacDoppler Controlling the IC-9700
The new IC-9700 replaced the IC-9100 in our Portable Satellite Station. An updated version of MacDoppler is available which supports the IC-9700 and we tested MacDoppler using both the USB and CI-V interfaces. In both cases, MacDoppler handled the new radio including band and mode selection, doppler correction, and access-tone setting properly. Our setup uses an iMac running MacDoppler and MacLoggerDX for radio control, antenna control, and logging and a windows laptop running UISS and MMSSTV for APRS and SSTV. Our setup was easily accomplished by connecting the IC-9700’s CI-V interface to the iMac and the USB interface (for audio and PTT) to our windows laptop.
IC-9700 Display and Waterfall – Working FO-29
We’ve made about 50 contacts with the IC-9700 so far. The radio is a pleasure to use. The touch screen layout and functions are very similar to the IC-7300 and one does not need to spend much time with the manual to become comfortable using the radio. The Spectrum Scope and associated waterfall are really nice for operating with linear transponder satellites. The screenshot above shows the IC-9700 display while working contacts using FO-29. As you can see, it is very easy to see where stations are operating in the passband of a linear transponder. The Spectrum Scope also makes it very easy to locate your signal in the satellite’s downlink and then adjust the uplink/downlink offset for proper tone.
We’ve also done a bit of APRS operation through the ISS using the IC-9700 and the UISS software. The direct USB interface was used to a windows laptop for APRS. Setting up PTT and the proper audio levels were straightforward and the combination of MacDoppler controlling the VFO in the radio and the PC doing the APRS packet processing worked well.
The IC-9700 can power and sequence our external ARR preamplifiers and we plan to use this capability to eliminate the outboard sequencers that we are currently using with our preamps. We’ll need to climb our tower to change the preamps over to be powered through the coax before we can complete the preamp control changeover.
All in all, we are very happy with the new IC-9700 for Satellite operations. We’ve also noticed that quite a few satellite operators also have the new IC-9700 on the air.
You can find other articles about our Satellite Station 4.0 project here:
It is winter here in New England and it is not the best time of year to work outdoors. I have been able to complete a few finishing touches on our new Satellite and 6m Tower.
Installed IP Camera
The first enhancement is the addition of an SV3C IP Camera. The camera allows us to see what is going on with our antennas. The camera has IR illumination so we can see our antennas when operating at night as well. The camera will also be useful for demonstrations when we operate our satellite station remotely in the future. This camera can use Power Over Ethernet (PoE) for power and is compatible with most popular security and webcasting applications.
The video above is from our IP Camera while our antennas are tracking AO-7 during a high-elevation pass.
The second enhancement relates to VU Mode (or J Mode) satellites such as SO-50 and FO-29 which use a 2 m uplink and a 70 cm downlink. Satellite ground stations are prone to problems with 70cm downlink receiver desensitization when transmitting on a 2m uplink. The symptom of this problem is difficulty in hearing your own transmissions in your downlink receiver while being able to here other operators in the downlink just fine. Our antennas are separated enough here that we have only minor problems with J Mode desensitization at our station. Fortunately, this is not a difficult problem to take care of.
Comet CF-4160N Duplexer
Installation of a good quality duplexer in the 70 cm path between the antenna and electronics such as our 70 cm preamp provides about 60 dB of additional isolation when operating in J Mode. The Comet CF-4160 Duplexer is a good choice for this application.
Duplexer J Mode FIlter Installed In Preamp Box
We added one to the preamp box on our tower to create a J Mode desensitization filter. The duplexer is mounted on the left side of the 70 cm preamplifier which is on the right side in the image above. The 70 cm output of the duplexer connects to the feedline from our 70 cm antenna and the common output goes to the input of our 70 cm preamp. We also added a connector cap to the unused 2 m port on the duplexer to protect it from moisture. You can read more about this approach to J Mode desensitization filtering here.
The next stage of our project will be to add hardlines to our new tower and install a second entry to our shack near our new tower to bring our feedlines and control cables permanently into our shack. These projects will have to wait until spring. For now, we are enjoying operating our new antennas from a temporary station set up in our house. We also have a new IC-9700 Transceiver on the way and we should have it installed sometime during the next couple of months.
You can find other articles about our Satellite Station 4.0 project here:
This article explains how to put a Sat Tracker together.
The information and software described here are provided on an “as is” basis without support, warranty, or any assumption of liability related to assembly or use. You may use information and software image here only at your own risk and doing so releases the author and Green Heron Engineering from any liability for damages either direct or indirect which might occur in connection with using this material. No warranty or liability either explicit or implicit is provided by either AB1OC or Green Heron Engineering.
Now that we have that out-of-the-way, here are the components that you need to build your own Sat Tracker:
The Sat Tracker image includes a display driver for the specific touch display listed above and will most likely NOT WORK with any other touch display. You will also need a Green Heron RT-21 Az/El or a pair of Green Heron RT-21 single rotator controllers from Green Heron Engineering that are properly configured for your rotators.
If you have not worked with the Raspberry Pi before, it’s a good idea to begin by installing NOOBS on your SD card and getting your Raspberry Pi to boot with a USB Keyboard, USB Mouse, and an HDMI display attached. This will give you a chance to get familiar with formatting and loading your SD card with the Raspbian build of the Debian OS for the Raspberry Pi. I’d encourage you to boot up the OS and play with it some to get familiar with the OS environment before building your Sat Tracker.
Etcher Writing Raspberry Pi SD Card Image
The first step in building your Sat Tracker is to put together the hardware and write the image to your SD Card. Use the enclosed instructions or search the web to find information on how to do each of these steps:
Install the Heat Sinks on the Raspberry Pi 3 B+ Motherboard. Make sure your chipset heat sink will clear the back of the case. If it won’t, it’s fine to just install the CPU Heatsink.
Assemble your case to the point where it is built up to support the touch display
Carefully install your touch display on the Raspberry Pi Motherboard
Install the remaining pieces of your case including the nylon screws and nuts which hold the case parts together
Download the SD Card image from the link below, unzip it, and load the image onto your SD card using Etcher
Install your SD card in the slot on your Raspberry Pi Motherboard
Connect your Raspberry Pi to the outside world as follows:
Connect Two USB cables – one end to the Elevation and Azimuth ports on your Green Heron Engineering RT-21 Controller(s) and the other ends to two of the USB connections on the Raspberry Pi
Connect a wired Ethernet Cable to your Raspberry Pi via a common Ethernet Hub or Switch with a PC or Mac that has VNC Viewer Installed. You will need a DHCP server running on the same network to supply your Raspberry Pi with an IP address when it boots. Your router most likely provides a DHCP function.
Connect your USB power supply to the Raspberry Pi Motherboard and power it up
Your Sat Tracker should boot up to the desktop with GH Tracker V1.24 running. The touch display works fine for using GH Tracker but its a bit small for configuring things. To make the configuration steps easier, the image comes up running VNC Server. I like to use VNC Viewer on my PC to connect to the Sat Tracker using VNC to perform the steps that follow. Note that both the Raspberry Pi and your PC must be on the same sub-network for the VNC connection to work. I’ve also included the following commands in the Sat Tracker image which can be run from the Raspberry Pi terminal window to make the configuration process easier:
$ setdisp hdmi # Disables the TFT display & uses the HDMI interface
$ setdisp tft # Disables the HDMI interface & uses the TFT display
$ reboot # Reboots the Raspberry Pi causing
# the latest display command to take effect
If you select the HDMI interface, you will find that VNC Viewer produces a larger window enabling you to perform the following configuration steps:
First, you need to determine the IP address of your Sat Tracker. This can be done via your DHCP server or by touching the network icon (up and down arrows) at the top of the display on the Sat Tracker.
Use VNC Viewer on your PC or Mac to connect to the IP address of your Raspberry Pi. The default password is “raspberry“.
Once you are connected, open a terminal dialog on the Sat Tracker, set your display to hdmi mode via the command shown above, and reboot your Sat Tracker.
Reconnect VNC Viewer to your Sat Tracker and click on the Raspberry button (Start Menu Button) at the top left of the screen, select Preferences, and run Raspberry Pi Configuration. Select Expand Filesystem from the System Tab. This will expand the filesystem to use all of the available space on your SD Card. You can also change the system name of your Sat Tracker and your login password if you wish. When you are done making these changes, reboot your Sat Tracker.
Reconnect to your Sat Tracker via VNC Viewer and select Setup-> Rotator Configuration from the menu in the GH Tracker App. Select the TTY devices (i.e. COM Ports) associated with the Azimuthand Elevationconnections to your RT-21 Controller(s) via the two dropdown boxes. You can also configure the operational parameters for GH Tracker at this time. The ones that I use with our Alfa-Spid Az/El Rotators are shown below.
GHE RT-21 Az/El Controller Settings for Alfa-Spid Rotator
Set via MacDoppler. Minimize wind loading and coupling to antennas below. Also enables water drainage from cross-boom tubes.
Azimuth dead spot is South. Elevation headings are from 0 to 180 degrees.
Minimize relay operation during computer tracking
Creates smooth start and stop for large array
Makes large movements relatively quick
CCW and CW limits ensures predictable Azimuth heading for range around 180 degrees. Elevation limits permit 0 to 180 degree operation. Elevation limits shown can only be set via GHE configuration app.
Alfa-Spid Az/El Rotator
Rotator has 1 degree pointing accuracy
Creates smooth start and stop for large array
Easy to read in shack
Configure the source of tracking data to be MacDoppler (UDP) from the GH TrackerSourceMenu. We use UDP Broadcasts with MacDoppler running on the same Mac with VNC Viewer to run our rotator. Finally, press the Press to start tracking button on GH Tracker and run MacDopplerwith UDP Broadcast on and Rotators Enabled to start tracking.
MacDoppler Tracking AO-91
Once you are satisfied with the operation of your Sat Tracker, use VNC Viewer to access the terminal window on your Sat Tracker one last time, set your display to TFT, and reboot.
The most common problems that you’ll run into are communications between your Sat Tracker and your Green Heron Engineering RT-21 Controller(s). If the Azimuth and Elevation numbers are reversed in GH Tracker, simply switch the TTY devices via the Setup Menu in GH Tracker. Also, note that it’s important to have your RT-21 Controller(s) on and full initialized BEFOREbooting up your Sat Tracker.
Most communications problems can be resolved by initializing your tracking system via the following steps in order:
Start with your RT-21 Controller(s) and you Sat Tracker powered down. Also, shutdown MacDoppleron your Mac.
Power up your RT-21 Controller(s) and let the initializations fully complete.
Power up your Sat Trackerand let it fully come up before enabling tracking in GH Tracker.
Finally, startup MacDoppler, make sure it is configured to use UDP Broadcasts for Rotator Control and make sure that Rotators Enabled is checked.
The VNC Server on the Sat Tracker will sometimes fail to initialize on boot. If this happens, just reboot your Sat Tracker and the VNC Server should initialize and enable VNC access.
I hope you have fun building and using your own Sat Tracker.
Sometimes we learn from problems and mistakes. We all go through this from time to time. It is part of the learning aspect of Amateur Radio. My most recent experience came while integrating our new tower-based satellite antenna system. After the antennas were up, initial testing revealed the following problems:
After an initial attempt to correct these problems with the antennas on the tower, we decided to take them down again to resolve the problems. The removal was enabled, in part, via rental of a 50 ft boom lift.
The lift made it relatively easy to remove the Satellite Antenna Assembly from the tower. We placed it on the Glen Martin Roof Tower stand that was built for the Portable Satellite Station 3.0. Once down, the Satellite Antenna System was completely disassembled and a replacement Alfa-Spid Az/El rotator was installed.
Cross Boom Truss System
The photo above shows the reassembled cross boom and associated truss supports. Note the tilt in the truss tube on the left side. This allows the antennas to be flipped over 180 degrees without the truss contacting the mast.
As mentioned in the previous article, polycarbonate reinforcement bushings are installed in the fiberglass parts to prevent the clamps from crushing the tubes. The photo above shows one of the bushings installed at the end of one of the truss tubes.
The bushings are held in place with small machine screws. This ensures that they remain in the correct locations inside the fiberglass tubes.
Thorough Ground Test
With the Satellite Antenna Array back together and aligned, we took a few days to operate the system on the ground. This allowed me to adequately test everything to ensure that the system was working correctly.
Tower Integration Using A 50 ft Boom Lift
With the testing complete, the antennas went back up on the tower, and the integration and testing work resumed. Having the boom lift available made the remaining integration work much easier.
Control Cable Interconnect Boxes On The Tower
There are quite a few control cables associated with the equipment on our new tower including:
The M2 Orion Rotator which turns the mast that holds the 6 m Yagi and the Satellite Antenna Array
A combination of junction boxes near the top of the tower and at the base make connecting and testing of the control circuits easier and more reliable. Tower mounted junction boxes were used to terminate the control cables near the rotators and antennas.
The Preamp System was mounted near the top of the new tower and the feedlines from the 2m and 70 cm Satellite Antennas were connected to it. LMR-400uF coax is run from the Preamp System as well as from the Directive Systems DSE2324LYRM 23 cm Satellite Yagi and the M2 6M7JHVHD 6 m Yagi on our new tower to the station in our house to complete the feedlines. These LMR-400uF feedlines will be replaced with 7/8″ hardline coax to our shack in the spring when warmer weather makes working with the hardlines easier.
Temporary Station Setup
With all of the tower integration work done, we set up the station in our house for testing. This is the same station that is our Portable Satellite Station 3.0 with two additions:
An iMac Computer which replaces the MacBook laptop used in the portable configuration
Both of these additions will become part of the final Satellite Station 4.0 when it is moved to a permanent home in our shack.
The rotator set up on the new tower provides two separate azimuth rotators. The lower one above turns both the 6 m Yagi and the Satellite Antenna Array together. The upper box controls the Alfa-Spid Az/El rotator for the satellite antennas. Using two separate rotators and controllers will allow us to integrate the 6m Yagi into the microHam system in our station and will allow the MacDoopler Satellite Tracking Software running on the iMac to control the Satellite Antennas separately. When we are using the 6 m Yagi, the Satellite Antennas will be parked pointing up to minimize any coupling with the 6 m Yagi. When we are using the Satellite Antennas, the rotator that turns the mast will be set to 0 degrees to ensure accurate azimuth pointing of the Satellite Antennas by the Alfa-Spid Az/El rotator.
PSK Reporter View using the M2 6M7JHVHD 6 m Yagi
So how does it all perform? With WSJT-X setup on our iMac, I was able to do some testing with the new 6 m Yagi using FT8. The IC-9100 Transceiver that we are using can produce 100W with WSJT-X. The 6m band is usually not very open here in New England in January so I was quite pleased with the results. As you can see from the PSKReporter snapshot above, the new antenna got out quite well on 6 m using 100W. I made several contacts during this opening including one with W5LDA in Oklahoma – a 1,400 mi contact. The 6M7JHVHD is a much quieter antenna on the receive side which helps to make more difficult contacts on 6 m.
MacDoppler Tracking AO-91
We’ve made a little over 100 satellite contacts using the new system so far. With the satellite antennas at 45 feet, it’s much easier to make low-angle contacts and we can often continue QSOs down to elevation angles of 5 degrees or less. I have not had much of a chance to test 23 cm operation with AO-92 but I have heard my signal solidly in AO-92’s downlink using the L-band uplink on the new tower. This is a good sign as our IC-9100 has only 10W out on 23 cm and we are using almost 100 ft of LMR-400uF coax to feed our 23 cm antenna.
Satellite Grids Worked and Confirmed
I’ve managed to work 10 new grid squares via satellites using the new antenna system including DX contacts with satellite operators in France, Germany, the United Kingdom, Italy, Spain, and Northern Ireland using AO-07 and FO-29. These were all low-angle passes.
So what did we learn from all of this? Due to concern over possible snow here in New England, I did not take the time to fully ground test the satellite antennas and new rotator before it went up on the tower the first time. My thinking was that the setup was the same as that used on Portable Satellite Station 3.0 for over a year. The problem was the replacement parts and new control cables were not tested previously and both of these created problems that were not discovered until the antennas were at 45 feet. While it would have made increased the risk that the antennas would not have gotten up before the first winter snowstorm here, it would have been much better to run the antennas on the ground for a few days as I did the second time. Had I done this, both problems would have appeared and have been easily corrected.