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.
What goes into an 11A Field Day? Well, for starters, 13 stations! We got together at AB1OC/AB1QB’s QTH a couple of weekends ago to set up ALL of our Field Day stations at once and test them together. Here’s a rundown of our final Field Day Station Test…
The Nashua Area Radio Society does a pretty big Field Day Operation each year. We will be 11A for Field Day 2019 with 4 towers up. Did you ever wonder what goes into pulling off a Field Day this large? Well, it’s all about planning and preparation. Take a look at the article above to see some of the preparation that we are doing for Field Day 2019.
The Nashua Area Radio Society participated in Winter Field Day for the first time this past weekend. We put up a 40 ft tower and we were QRV on all allowed bands from 160m through 2m and 70cm. Our station was a four transmitter one and we produced a great score during the 24-hour operating period. Winter Field Day presents some unique challenges that we did not encounter during Summer Field Day.
We put together a station for 160m for the first time as well as some other new things. You can read all about our approach to a station and operating for Winter Field Day via the link above.
We are just awaiting notification of the final date and time for our contact and we’ll begin final setup and testing at HMS.
We’ve been sharing our progress as we’ve on the Nashua Area Radio Society’s Youth Forum as we have worked through our final preparations. I also would like to share a summary here along with some insights on what we’ve learned along the way.
An ISS Crew Contact is No Small Undertaking …
We have been working for almost a year now to get ready for our contact. We’ve built and tested two space ground stations and we’ve discovered and addressed several performance and reliability issues with these stations during trial deployments at Field Day, Ham Fests, License Classes, and during testing here at our QTH.
Dave, K1DLM who is a member of NARS had extensive professional sound experience and was able to help us with this part of our project.
Dave put together a professional-level A-V system design to support our contact and provided much of the gear to realize the design. His uses a pair of communications microphones, a pro-mixer, and audio interface gear to provide student and radio audio to the sound system in the auditorium at HMS as well as to an array of video cameras. The system makes extensive use of XLR cabling and pro-level devices to ensure clean audio.
Video Presence on the Internet is an Important Element to Draw Interest in a Project Such as Ours…
We Live Streamed some of our Station Testing activities to Facebook and we were amazed at the interest and response that we received. Many folks worldwide followed our progress on Facebook in real-time as we set up and completed our full station test.
We are planning to have two IP Video Cameras Live Streaming to Facebook during our contact. One in the room to provide video of the students as they talk with the astronaut on the ISS and a second on our antennas as they track the ISS.
Its Critically Important to Test the Complete Station Ahead Of Time – New Challenges Emerged when we Mixed Audio and Radio Gear…
We set up the full station (Primary and Backup) along with all of the Audio and Video Gear about 3 weeks prior to our contact for a complete system test. We learned a great deal in doing this and we encountered several problems which we have since corrected.
The most important issues did not show themselves until we made some contacts with all of the A-V gear in place. We had problems with RF aggravated ground loops in the radio microphone circuits during the initial test. These problems did not show themselves until we added the audio mixer and sound system into the station.
These problems were easily corrected by adding Audio Isolation Transformers into the radio microphone circuits.
We also solved some potential issues related to level differences between line and microphone audio circuits using Audio Attenuators.
These problems were not difficult to solve but they would have seriously degraded our contact if we had not discovered them early while there was still plenty of time to secure parts and retest.
Data Networks in Schools and Public Places Require Configuration Adjustments to Support Contact Elements…
Schools and other public places typically do a good job of protecting their data networks and users from threats from both the Internet and within the venue. Tracking Programs, IP Cameras for Live Streaming, and other contact support gear are not typical devices that would be in operation on such networks. Also, many public venues rely almost exclusively on WiFi for access to the Internet and typically prohibit or severely limit client devices from communicating with each other.
WiFi can often suffer from RF interference issues when many devices like Smart Phones are located together in a small area. This situation is common in large gatherings.
Data System for ISS Contact
We had quite a bit of experience with these problems as part of other school projects we’ve done. We worked closely with the IT staff at HMS to plan for and create a network design to support our contact. We opted to use a wired network approach with a local Ethernet switch to implement the IP communications between the elements in our stations and the associated IP Cameras.
The IT team at HMS configured their network to ensure that the IP addresses of our devices were fixed in DHCP and that devices that needed access to the Internet had the access that they required. The IP cameras where the most challenging elements here.
Packed and Ready to Go…
Well, all of our gear is packed and ready to go for setup on-site at HMS. The next article in this series will cover the on-site set up for our contact.
The performance of the 3.1 Station’s antennas is very good but the antenna system is a handful to transport. We are planning to install these antennas on a new tower at our QTH and use our Flex-6700 SDR-based Remote Operating Gateway with some upgrades to create a remotely controlled satellite station that can be operated via the Internet. The main components of the 4.0 Station will include:
Upgrade plans for our Transportable station include the addition of remote switchable polarity relays and a new Icom IC-9700 Transceiver when it becomes available.
Polarity Switch Installed in LEO Pack Antennas
The polarity switches have been installed on the M2 Antennas 436CP16 and 2MCP8A antennas in our M2 Antennas LEO Pack. We are using a DX Engineering EC-4 console to control LHCP or RHCP polarity selection on the antennas. We have been doing some testing with the upgraded LEO pack which includes the polarity switching capabilities and we are seeing a significant improvement in performance.
AlfaSpid Az-El Rotator
We are also planning to move the upgraded LEO pack antennas to the current 3.1 Tower to take advantage of the AlfaSpid Rotator which is installed there.
Icom IC-7900 Transceiver
The other major upgrade planned for the 2.2 Station is the new Icom IC-9700 Transceiver when it becomes available. This radio will utilize Icom’s SDR platform and includes a Pan Adapter/Waterfall display which will be a very useful addition for operation with Linear Transponder Satellites.
Upgraded Portable 1.2 Station
We really enjoy mountain topping and activating grid squares so we are planning upgrades to our 1.2 Station for this purpose.
Our 1.2 Portable Satellite Station on Mt. Kearsarge
The 1.2 Station utilizes computer control to enable operation with linear transponder satellites and will use solar/battery power along with a 100w/70w Icom IC-910H Satellite Transceiver.
A pair of 90W foldable solar panels, an MPPT solar charger, and a pair of LiPo 4S4P A123 batteries provide plenty of power to run the IC-910H Transceiver and the associated computer. The portable station also includes a pair of ARR preamps.
Portable Satellite Antenna System
The antenna system we’ll be using is an Elk Portable Log Periodic 2m/70cm yagi on a camera tripod. A combination of a compass and an angle finder gauge helps us to correctly point the antenna.
As you can probably tell, all of these upgrades are in progress and are at various stages of completion. We will post updates here on our Blog as we continue to make progress. Here are links to some of these posts:
Quite a few Nashua Area Radio Society members have been working on a display to get young people and potential new Hams interested in Amateur Radio. Our display will be part of the New England Amateur Radio Convention in Boxboro, MA on September 8th and 9th. We are also planning a similar display for NEAR-Fest at Deerfield Fairgrounds, NH later in the fall. You can see more about our planned display and the associated hands-on activities via the following link.
I want to share some information about an Amateur Radio event that we will be doing at the Boxboro, MA Ham Radio Convention in September. Our display and hands-on activities provide an introduction to Amateur Radio for young people and include information and a chance to try Amateur Radio activities such as:
You can read more about our plans for the event via the link above.
Morse Trainer Kit
We’ve been working with Steve Elliot, K1EL to develop an inexpensive kit building project to include as part of our displays. We will be including a new kit building activity in as part of our display. Builders can purchase the Morse Trainer Kit shown above for $20 and build it at the show. We will provide soldering equipment and kit building mentors to help builders complete their kit. The package includes batteries and a printed manual. We will have these kits available for walk-up purchase at the show on both Saturday and Sunday.
I am also planning to provide forum presentation on the following topics on Saturday at Boxboro:
Creating Successful Youth Outreach Projects
Portable Satellite Station Design, Operation, and Planning for an upcoming ISS Crew Contact
STEM Learning for Young People via High Altitude Balloons Carrying Amateur Radio
Our 40m V-Beam antenna was initially designed in EZNEC 5.0. It was manually optimized for decent gain and front to back performance and it worked quite well. Recently, we decided to try automatic optimization software on the antenna as part of a tune-up on the design for Field Day 2018. After looking around on the Internet a bit, we discovered a software package called AutoEZ which looked ideal for my project.
AutoEZ Antenna Modeling and Optimization Software – Wires Tab
The first step in the project was to rebuild the EZNEC model that I already had for our 40m V-Beam antenna in AutoEZ. I began by defining several AutoEZ Variables and Excel Formulas in the AutoEZ Variables Tab that enabled me to easily modify the design of the antenna and to optimize it. Some of the basic variables included the target design frequency for the antenna, the height and separation of the antenna elements, the distance to the element anchor points, and the length of the element wires.
AutoEZ Antenna Model Variables (Formula View)
The image above shows the model variables in “Formula View”. You can see some of the math and trig functions that were used to compute values for some of the variables. AutoEZ can only optimize variables that do not contain formulas so I was careful to ensure that the base separation between the elements and the length of the element wires were constants as these are the parameters that I wanted to optimize later.
AutoEZ Antenna Modeling and Optimization Software – Wires Tab
Excel Trig formulas and the Variables were used on the Wires Tab to determine the coordinates of the wires in the antennas. There are a total of 7 wires in the model. Six are the two ends of the three inverted-V elements. The Seventh wire is a short 4″ section in the middle of the Driven Element to allow a current source to be inserted to drive the antenna there. I was careful to create an accurate model of the wire gauge, insulation, and loss that we are using for our V-beam
Model Variables to be Optimized
With the model built, it was back to the Variables Tab to select the parameters to be optimized. Optimization is best done as a multi-pass process and I did this in two steps. The first set of runs included optimization of both the element spacings and their lengths. This led me to conclude that the mast spacing of 27 ft (Driven to Director) and 28 ft (Driven to Reflector) were the best choices. I then set these as fixed values in the variables tab and ran the optimizer a second time with some starting element lengths to optimize the element lengths by themselves.
One must create a set of frequencies and objectives for the optimizer before running it. This is done in the AutoEZ Optimize Tab. The antenna is being used for SSB on 40m so I choose a range of frequencies that covered the SSB sub-band on 40m. Note that I weighted the center frequency heavier than the edges by including it more times in the optimizer’s list. The use of the Optimization Objectives and their associated weights and values are well covered in the AutoEZ documentation so I won’t cover them in detail here. The parameters above were chosen to create a reasonable balance between SWR values across the 40m SSB sub-band, good Front/Back and Front/Side performance from azimuth values ranging from 60º to 300º, and a reasonable amount of forward gain for a 3 element antenna of this type.
I expected that the final impedance of the antenna would be a typical value for a yagi in the 20 to 30 ohm range. Thus, I set the SWR calculations based upon a 25 ohm target impedance. More on the matching of the resulting design later…
Element Optimization Results
It took several runs of the optimizer with different sets of Optimizer Objectives to get the final results I was looking for. The Optimizer tried 130 combinations of element lengths to arrive at the final lengths shown above. Note the improvements in SWR (1.6 -> 1.04), Forward Gain (+1 dB), Front/Back (+4.2 dB) and Front/Rear (actually Front/Side) performance that the Optimizer was able to achieve over my manual, trial and error optimization.
Post-Optimization Model Variables
Next, I rounded the optimized element lengths and plugged them into the Variables Tab.
Post Optimization Azimuth Pattern
The image above shows the optimized Azimuth pattern for the antenna as generated by AutoEZ and EZNEC. A very clean result!
Post-Optimization Elevation Pattern
And here’s the optimized Elevation pattern near the center of the SSB sub-band. This antenna is a little low for 40m but the resulting maximum gain at a 35º angle should work well for US contacts during Field Day.
Calculated Performance for the Optimized Antenna
The final step in the optimization process was to calculate a full set of performance calculations for the antenna using the Calculate Tab. AutoEZ makes it very easy to generate a set of Test Cases for incremental frequencies in the SSB sub-band on 40m. Note the setting of the Elevation angle of 35º to match the maximum gain angle for the optimized antenna. Also, note the parameter settings for Ground Type and Characteristics. I set these to model the less than ideal soil conditions that we have here in New England.
Performance Plots for the Optimized Antenna
AutoEZ provides several nice graphical capabilities via the Patterns, Triple, Smith, Custom and Currents Tabs. I used some of them to plot the data from the performance calculations. These graphs help to visualize the results of the optimization to verify that the design objectives for the antenna have been met.
We are looking forward to using the optimized version of our 40m V-Beam at Field Day 2018. It took me a couple of days of time to read all of the AutoEZ documentation and learn to use the excellent tools it provides. I don’t think I will build another EZNEC antenna model without using AutoEZ. Even without the optimization features, AutoEZ makes the construction and modification of an antenna model in EZNEC far easier than it would be using EZNEC alone. I hope that you’ll give AutoEZ a try for your next antenna design project.
Power supplies and power distribution for the Transceiver, Amplifier, and Accessories
All of the equipment needed to upgrade our 2.0 Portable Station to 2.1 is either here or will arrive shortly. Here’s some more information on the planned equipment.
Icom IC-910H Transceiver
The Icom IC-910H was Icom’s flagship Transceiver for Satellite work before the IC-9100 was released. It’s a very nice satellite radio! Dave, K1DLM graciously lent us his IC-910H for use in our backup station.
Green Heron RT-21 AZ/EL Rotator Controller
We already have a Green Heron Az/El Rotator controller setup for the Yaesu Rotator system on the 2.0 Antenna Tower and we will be reusing it for the 2.1 station.
The final new component in our 2.0 to 2.1 upgrade is the addition of a 200W RM ITALY LA 250 power amplifier. We have opted for the version of this amplifier with the cooling fans. The unit is very well made and we are anxious to see how it performs on the air.
Some of our readers might be wondering what we are planning to do with all of Portable Satellite Ground Station equipment in the long run? We plan on keeping the 1.0 Portable Station for grid square activations and demonstrations. Its simple, battery-powered approach and small antenna make it ideal for this sort of work.
The upgraded 2.0 Portable Station with its enhanced polarity switching will become our transportable station for License Class and Field Day use. It will be converted at the end of 2018 to use our Icom IC-9100 Transceiver that is currently part of the 3.0 station.
We plan to use the Portable 3.0 Station through the year (2018) to support the planned ARISS contact, Field Day, and some demonstrations at local Ham Fests and schools. Once these are complete, we plan to permanently install it here at our QTH and it will become our main satellite ground station at our home QTH.
You can view all of the articles about our Portable Satellite Stations via the links below.
We will begin construction of the 2.1 upgraded station once a few remaining components arrive here. We plan to share some more about the construction and initial testing of our 2.1 Portable Station here.
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.