We had some time over the weekend so we ran some Satellite Pass Predictions for Field Day 2021 for our Grid Square which is FN42. As you can see, we are going to have a lot of fun working satellite during Field Day! Field Day rules limit us to a single FM EasySat contact using but we can work as many contacts via Linear Transponder Satellites as we wish
Field Day Satellite Station
We recently set up and tested our Portable Satellite Ground station here at our QTH and it’s working great! It has produced some good DX contacts into Europe from New Hampshire, USA during the past week.
The Nashua Area Radio Society will be using our portable Satellite Station this year at Summer Field Day. A number of members got together recently to assemble and test our Computer-Controlled Portable Satellite Station for Field Day. Here are some pictures of our Field Day Satellite Station Test…
Several members of the Nashua Area Radio Society got together to set up and test our Portable Satellite Station for Field Day 2021. Our station is a computer-controlled one and enables us to work FM and Linear Satellites using phone mode and CW.
You can see how the portable station goes together in the article above. You can learn more about the design and construction of our Portable Sation from the series of articles that begins here. We hope to work some of our readers on the birds during Field Day this year!
We’ve been making good use of our Satellite Ground Station. Our existing 2MCP14 and 436CP30 antennas have enabled us to make over 2,000 satellite contacts; working 49 of the 50 U.S. States, 290+ Grid Squares, and 31 DXCCs. Our station is also an ARISS Ground Station which enables us to help Schools around the world talk to astronauts on the ISS.
The first step in the project was to unpack and carefully inventory all of the parts for each antenna. This included carefully presorting and marking each element as we did during the assembly of our EME antennas.
2MCP22 Completed Antenna
The new antennas are quite large and they took most of the available space in our workshop during assembly. Getting good results from any antenna is all about attention to the details. Small things like turning the boom sections to get a good alignment of the elements, using NOALOX on the boom sections and hardware to prevent corrosion and galling, carefully measuring and centering the elements, etc. are all good things to do.
2MCP22 Feedpoint Assembly including Polarity Switch Upgrade
The feedpoint system on these circular polarized antennas requires careful attention during assembly. It’s important to install drive element blocks, shorting bars, polarity switches, feedpoint splitters, and all phasing lines EXACTLY as shown in the antenna assembly manual. Failure to do these steps will likely results in SWR problems down the road.
436CP42UG Feedpoint Assembly
The images above show the feedpoint assemblies for both of our new antennas.
New Satellite Yagis Ready For Installation
A rough SWR measurement with the antennas on the ground was performed to check for assembly errors. It’s a good idea to use a 12V battery to test the antenna SWR’s in both RHCP and LHCP. These tests checked out fine and we are ready to begin installing the antennas on our Tower.
Old Antenna Takedown and Work Stand
Old Antenna Assembly Takedown Using Boom Lift
The next step in the installation was to take down our existing antennas. We rented a 50 ft Boom Lift for the project. The lift makes the work much easier and safer.
It’s important to fully test a complex antenna system like this on the ground prior to installation on a Tower. We have routinely found and corrected problems this way. This approach also enabled us to properly adjust our cross boom and antenna support trusses and balance the final assembly properly. All of the required adjustments are MUCH easier with the antennas on the ground.
We also run our rotators under computer control for at least one full day before installing the completed assembly on our Tower. We have consistently found and corrected problems with cabling and balance this way.
Antenna Mounting and Trussing
2MCP22 Boom Truss
The new antennas have very long booms (approximately 18 ft) and they have a tendency to sag. Add the ice and snow load that we experience here in New England and you end up with quite a bit of stress on the booms over time. Robert at M2 Antenna Systems came up with a custom truss assembly for our installation to address this problem. It’s important to minimize any metal in a setup like this to avoid distortion of the antenna patterns. The trusses use a solid fiberglass rod and small turnbuckles to support the ends of each antenna boom. There is much more weight on the rear of the booms due to the weight of the attached coax cables and polarity switches. For this reason, we located the truss anchor point for the rear of the boom such that it creates a sharper angle for the truss ropes at that end of the truss. This reduces the compression load on the rear of the boom and enables the truss to better carry the weight at the back of the antenna.
436CP42UG Boom Truss
Installing a truss on the 70cm yagi is much trickier due to the tight pattern of this antenna. We minimized the added metal components by drilling the antenna boom to mount the truss plate directly to the boom via bolts.
We relocated the boom support plates on both antennas as far to the rear of the largest boom sections as possible to improve overall antenna balance. The clamps were also adjusted to change the orientation of the elements from vertical/horizontal to a 45-degree X arrangement. This maximizes the separation between the element tips and other metal components like the cross boom and truss plates.
Tubing Drill Guide
All of this required drilling some new holes in our antenna booms. We used a Tubing Drill Guide and C-clamps to perform the required drilling operations accurately.
Satellite Antenna Boom Assembly
The photo above shows the new antennas mounted on our cross boom. The modifications worked out great resulting in well supported and aligned antennas on the cross boom.
Balancing The Array
Cross Boom Counterweight and Trusses
It’s very important to properly balance any antenna assembly that is used with an elevation rotator. Failure to do this will usually result in the failure of your elevation rotator in a short period of time. We initially had some pretty major balance problems with our new antennas. This is due, in part, to the weight of coax cables that run from the antenna feed points along the L-Brace Assemblies. The added weight of the Polarity Switches near the rear of the booms was also a significant contributor to this problem.
We created a counterweight by replacing one of our cross boom truss tubes with a metal section of pipe about 4 ft long. The pipe acts as a counterweight to the weight of the coaxes, etc.
Wheel Weights Used for Balancing
Next, we added 4 1/2 pounds of weights to the front on the metal pipe. We used several layers of Wheel Weights built up in multiple layers to get the necessary counterweight. A heavy layer of electrical tape and some large cable ties were used to ensure that the weights say in place.
This got us close to a good balance but the boom of the 2MCP22 was still significantly out of balance. Matt at XX-Towers came up with a good solution to this problem. We added a few strips of wheel weights inside the very front of the boom of the 2MCP22 to finally get the antennas balanced. A combination of the adhesive tape on the weights and two small machine screws through the boom ensures that the weights remain in place and do not short the elements to the boom.
A final check and baseline of all of our antennas were made on the ground. Both RCHP and LHCP modes were checked and recorded for future reference.
432CP42UG Installed SWR
We found that some fine-tuning of the locations and routing of the phasing lines on our 436CP42UG improved the SWR curves. This is a common situation and it’s well worth the time to make small adjustments while carefully observing how they impact your SWR readings. The phasing cables are firmly secured to the antenna boom after the fine-tuning is complete.
New Antenna Installation and Integration on Tower
Upgraded Antennas Going On Tower
The next step in our project was to install the updated antenna assembly back on our Tower. We had to push the lower rotator and mast up about 4 ft to accommodate the larger antennas. We removed our 6M7JHVHD Yagi and temporarily fastened it to the side of our tower to make these steps easier. We also took the opportunity to work on our 6M7JHVHD Antenna to adjust the length of the Driven Element for better SWR performance in the FT8 and MSK144 section of the 6m band.
Satellite Tower Infrastructure and Accessories
There is quite a bit of feed line and control cabling involved in a complex antenna system such as ours. The next step in the project was to reconnect all of the cables and coax feedlines.
Control Cable Junction Box at the Base of VHF Tower
We use small junction boxes on our tower and a larger one at our tower base to make it easy to remove and reinstall all of the required control cables. Our approach was to hook up and test the rotators first to ensure that we did not have any new mechanical or balance problems. This step checked out fine. The stiffer chrome molly mast and its added length actually resulted in smoother operation of rotators than we saw during ground testing.
The final step was to work through the other control cables and feed line connections; testing each connection as we went. The Boom Lift makes this work much easier to do.
We took advantage of the availability of the Boom Lift and added some additional enhancements to our VHF Tower. Previously. changing the battery in our Weather Station involved climbing our main tower to 50 ft. We moved the weather station to the 30 ft level on our VHF tower to make this maintenance step easier.
Initial testing of our new antennas is showing some major improvements. The uplink power required to work LEO satellites has been reduced significantly. As an example, I have worked stations using the RS-44 Linear Satellite with just 0.4 watts of uplink power out of our Satellite IC-9700. The signal reports we’ve received have been excellent as well.
More About Our Ground Station
Here are links to some additional posts about our Satellite Ground Stations:
After a year’s worth of planning and 10 months of construction, we have our new 2m EME Antenna System installed on our EME Tower and working! This stage of our project took about a week and included a lot of help from Matt and Andrew at XX Towers.
Antenna Ground Test
The first step was to arrange the four 2MXP28 Yagis that we built on saw horses near our EME Tower and check each antenna’s vertical and horizontal SWR. Performing SWR measurements with the antennas close to the ground like this does not produce very accurate measurements. Doing this does allow one to spot potential problems if some of the measured SWR fail to show a resonance or are wildly different than the other antennas in the group. All of our antennas checked out as expected.
50 Ft Boom Lift, H-Frame Cross Boom Assembly On The Ground
We also rented a 50-ft Boom Lift and set it up near our EME Tower. A tool like this is almost essential to safely assemble and adjust a large, complex antenna system involving an H-Frame. It also speeds up the assembly and adjustment process considerably.
Elevation Rotator and H-Frame
Elevation Rotator Installation on Mast
The first step was to install the MT-3000A Elevation Rotator on the mast. We pre-installed the control cable for the elevation rotator before installing it on the tower. This enabled us to get it temporarily hooked up to the Rotator Controller in our shack so that we could adjust the elevation of the H-Frame and Antennas as we installed them.
With the H-Frame in place, we installed the upper 2MXP28 Yagi Antennas next. The image above shows the rigging of the boom trusses which was done on the Tower.
Lower Antenna Installation and Adjustments
Next came the lower 2MXP28 Yagis. We spent considerable time leveling and aligning all of the Antennas and H-Frame components at this stage.
Feedlines, Electronics, and Balancing
T-Braces and Feedlines
The T-Brace assemblies and Antenna Phasing Lines were installed next. Each Antenna requires two LMR-400 Phasing Lines and these coax cables add considerable weight to the backs of the Antennas. The T-Braces support these cables and help to align the Antennas on the H-Frame.
We replaced the Vertical H-Frame Boom Truss Pipe with a heavy section of Mast Pipe to act as a counter-weight and balance the final H-Frame and Antenna assembly. This step is critical to ensuring a long life for the Elevation Rotator’s drive system and chain.
Phasing Lines, Power Dividers, and Feedline Connections on Crossboom
The Rotator Loop contains the following cables and Coax Feedline connections from the H-Frame/Antenna assembly:
Vertical and Horizontal Rx Feedlines
Elevation Rotator Control Cable
MAP65 Housing Control Cable
All of these cables are bundled and securely fastened to the H-Frame Cross Boom and to the Tower. Andrew is a master at this sort of rigging!
Control Cable Connections at Tower Base
I took some time to finalize the Control Cable connections at the base of our tower. Time was spent with a voltmeter doing checks to ensure that everything was connected correctly and working. This effort resulted in the discovery and correction of some wiring errors and a faulty relay in the MAP65 housing. Had I not done these steps, we would have surely destroyed the Preamps in the MAP65 Housing when we transmitted for the first time.
Testing Our New Antenna System
Vertical Polarity Tx SWR at Shack
A series of SWR measurements were taken before sealing the coax cable connections on the tower. SWR measurements were checked and recorded for future reference at the following points in the feedline system:
At the ends of the phasing lines associated with each antenna
At the output of the two Power Dividers on the tower
At the shack entry ground block
Measurements were taken separately for both the Vertical and Horizontal elements of the final Antenna System. The image above shows a typical SWR measurement for our final Antenna System.
I did many final checks and adjustments while the Boom Lift was still here. These steps included:
Checking the oil level in the elevation rotator
Re-lubing the elevation rotator chain
Adjusting the limit switch stops on the Elevation Rotator to allow enough over-travel for future adjustments and maintenance
Checking all hardware for tightness
Sealing all coax cable connectors with Coax Wrap and Electrical Tape
Making some final adjustments to align the four 2MXP28 Antennas with each other and the H-Frame
Thanks to some great work by the ARISS Team, a new Voice Repeater system is operating on the International Space Station! Here is the access information:
Mode: FM Voice
Uplink Frequency: 145.990 MHz, PL 67.0 Hz
Downlink Frequency: 437.800 MHz
IORS Hardware and Kenwood Radio
The repeater uses the new InterOperable Radio System (IORS), a space-modified JVC Kenwood D710GA transceiver, and an ARISS developed power supply system.
Here’s some more information from the ARISS Press Release:
The ARISS team is pleased to announce that the setup and installation of the first element of our next-generation radio system was completed and amateur radio operations with it are now underway. This first element, dubbed the InterOperable Radio System (IORS), was installed in the International Space Station Columbus module. The IORS replaces the Ericsson radio system and packet module that were originally certified for spaceflight on July 26, 2000.
The initial operation of the new radio system is in FM cross-band repeater mode using an uplink frequency of 145.99 MHz with an access tone of 67 Hz and a downlink frequency of 437.800 MHz. System activation was first observed at 01:02 UTC on September 2. Special operations will continue to be announced.
The IORS was launched from Kennedy Space Center on March 6, 2020, on board the SpaceX CRS-20 resupply mission. It consists of a special, space-modified JVC Kenwood D710GA transceiver, an ARISS developed multi-voltage power supply, and interconnecting cables. The design, development, fabrication, testing, and launch of the first IORS was an incredible five-year engineering achievement accomplished by the ARISS hardware volunteer team. It will enable new, exciting capabilities for ham radio operators, students, and the general public. Capabilities include a higher power radio, voice repeater, digital packet radio (APRS) capabilities, and a Kenwood VC-H1 slow-scan television (SSTV) system…
I was able to work several stations using the new ISS Voice Repeater this morning. It is very sensitive and uses 5 watts of downlink power with a good antenna on the ISS. I was able to make solid contacts using the Ground Station here using only 1.5 watts uplink power when the ISS was at 10 degrees above the horizon. At least one of my contacts was with a station using an HT with a whip antenna!
The voice repeater is sensitive enough and uses a power level that will enable folks with an HT and a whip antenna to make contacts using the ISS when it is close to the horizon. It should also be easy to make contacts using mobile rigs that can support cross-band operation as well. Program your radios!
I’m looking forward to working you through the ISS!
We get quite a few requests from folks to explain how to get started with Amateur Radio Satellites. Requests for information on how to build a computer-controlled ground station for Linear Satellites are also pretty common. I recently got such a request from our CWA class so I decided to put together a session on this topic.
We covered a number of topics and demonstrations during the session including:
How to put together a simple station and work FM EasySats with HTs and a handheld antenna
A recorded demonstration of some contacts using FM EasySats
How-to build a computer-controlled station and work Linear Transponder Satellites
Fixed and Portable Satellite Station Antenna options
A recorded demonstration of some contacts using Linear Satellites
Tech Night – Getting Started in EME (Click to View The Presentation)
We recently did a Tech Night Program as part of the Nashua Area Radio Society’s Tech Night program.. I wanted to share the presentation and video from this Tech Night so that our readers might learn a little more about how to get started in EME or Moonbounce Communications.
April 2020 Tech Night Video – Getting Started in EME Communications
I have joined the ARISS Program as a Mentor to help schools make contacts with astronauts on the International Space Station (ISS). School contacts as part of the ARISS program can take two forms – Direct Contacts and Telebridge Contacts.
ARISS Direct Contacts
Direct contacts involve setting up a space communications ground station at the school making the contact.
ARISS Direct Contact Ground Station Antennas at Council Rock HS
Direct Contacts involve a great deal of preparation and a local Ham Club which has considerable VHF weak-signal experience and equipment to partner with on a school’s contact. There can also be considerable expense involved in assembling the necessary ground station for a Direct Contact. In addition, some locations are much better than others in terms of access to good, high-angle ISS passes and an environment that is relatively free of nearby obstructions like buildings, hills, etc.
Students at Maani Ulujuk High School in Rankin Inlet, Nunavut, Canada
Telebridge contacts involve using an existing ground station in a different location with an audio link to the school making the contact via telephone. This type of contact provides a high-quality experience with an astronaut on the ISS without the need to construct a ground station at the school. It enables the teachers involved in the contact process to focus on the educational aspects of their contact with the ISS.
All of the ARISS Telebridge Ground stations are built and operated to very high standards.
Also, schools in difficult locations or those who don’t have the needed support of a local Ham Radio club with the necessary space ground station equipment can still enjoy making a contact with an astronaut on the ISS. In addition, a Telebridge contact also enables the supporting Amateur Radio Club to focus on providing great Amateur Radio activities and educational support to their partner school.
Adding Telebridge Capability to Our Station
Space Communications Ground Station at AB1OC-AB1QB
We’ve used the station here to make many satellite contacts and to listen to ARISS contacts from the ISS. We’ve also used our station to receive images from the ISS during ISS SSTV events. We’ve decided to add a Phone Patch to our station here to enable it to be used as a testbed for schools preparing for Telebridge contacts.
Adding A Telephone Patch
Phone Patch To Enable Testing and Hosting Telebridge Contacts
A Telephone Patch enables a third party to communicate over an Amateur Radio link using a telephone. A Phone Patch provides a connection between a Transceiver and a telephone line. It also handles creating a proper balance at the 2-wire Hybrid Interface that connects to the telephone line to the radio. A typical Phone Patch device also provides for Transmit and Receive level adjustments.
Setting up the MFJ Phone Patch was pretty straightforward. All that was required to work with our IC-9700 Transceiver was to set the internal jumpers in the MFJ Phone Patch to configure its microphone connection properly. The MFJ Phone Patch came with a cable to connect to the round microphone jack on the IC-9700 Transceiver. A connection between our audio amplifier to bring audio into the Phone Patch was made to complete the installation.
Testing On The Air
The MFJ Phone Patch was adjusted to achieve a good balance on the 2-wire Hybrid Interface to the telephone line and the Transmit and Receive levels were properly adjusted prior to on-the-air use. These procedures are clearly explained in the manual for the MFJ-624E and are easy to complete.
With these steps complete, we set up a telephone call and made several contacts using FM stateless on the air. We received good audio reports and could easily understand the downlink audio using a standard telephone receiver.
Becoming an ARISS Telebridge Ground Station
My initial purpose for adding Telebridge capability to our ground station was to enable it to be used to perform testing of the audio systems in schools that will be hosting Telebridge contacts. I am also going to apply to become one of the ARISS Telebridge Ground Stations in North America. We have an emergency backup power system here and our station’s location in our home makes it a good choice for situations where contacts need to be made at any time of the day or night. More to come on this in the future.
More About Our Ground Station
Here are links to some additional posts about our Satellite Ground Stations:
Ann Stockbridge, Educator at Kennebunk’s Sea Road School
Regional School Unit 21 has been selected for an out-of-this-world opportunity. An international association of space agencies and Amateur Radio organizations has chosen RSU 21, represented by Sea Road School, to advance in a process climaxing in a conversation between students and astronauts aboard the International Space Station (ISS).
RSU 21 was one of 10 schools selected nationally to continue through the multi-month acceptance process. The contact event with the ISS could occur between July and December of this year.
The opportunity is provided by ARISS (Amateur Radio on the International Space Station), an association that includes NASA, the Center for the Advancement of Science in Space, the American Radio Relay League, the Radio Amateur Satellite Corporation, and space agencies in Canada, Japan, Europe, and Russia. They collaborate to enable students to communicate with ISS astronauts and help inspire interest in space, communications and STEM coursework.
As our readers may know, I have joined the ARISS program as a Mentor to help schools prepare for and make successful contacts with Astronauts on the International Space Station. I am working with Regional School Unit 21 Sea Road School teachers and local Ham Radio folks in Maine, USA to help them make contact with the ISS during 2H2020. The link above shares more about the STEM learning program that is being created around this contact.
Slow-Scan TV from the International Space Station (ISS) was on the air again late in December 2019. The ISS SSTV event was in memory of cosmonaut Alexei Leonov. We had our satellite station running to track the ISS and capture the SSTV images during the event. It’s pretty easy to receive these images – it can be done with an HT, hand-held antenna, and a laptop…
This article includes a gallery of the images that we received during the December 2019 ISS SSTV event and some how-to information that you can use to receive SSTV images from the ISS with just an HT and a handheld antenna.