We decided to put up a third tower as part of our 2017 Field Day operation. The new tower will support a tri-band yagi and wire antenna for use by our Digital and GOTA stations this year. Our Field Day plans call for this tower to be located on the middle-level soccer field at the Hollis-Brookline High School. To overcome terrain limitations, we decided that our new tower should be a 60 ft setup.
The project began with some mechanical design and planning for a new, heavy-duty Falling Derrick System. Mike K1WVO, Dave N1RF and I secured the necessary materials and hardware to make the new Falling Derrick System.
Equipment And Tools On Site
The team in the two pictures above met at our QTH this past weekend to transport all of the equipment for the new tower to the high school for a test setup.
Setting Up The Tilt Base
The first step in the test was to locate the tower base in the center of our test area and ensure that it was level. Steel stakes were driven and retainers added to secure the base to the ground.
Building The Derrick
Next, we assembled the falling derrick and the first section of the tower to the base.
Assembling The Tower
With the Derrick in place, we assembled the remaining sections of our 60 ft tower on the ground.
Driving Guy Anchors
WIth the tower, Derrick and base together; we carefully located and drove the steel stakes for guying the tower, the derrick and for anchoring the pulleys associated with the falling derrick system. With this done, we made up and attached two levels of guys between the tower and the anchor stakes.
Completed Heavy Duty Derrick System Ready To Lift
The tower is lifted by two wire cables which run between the derrick and the tower. We made these cables up to length during our test session. Multiple cables are used to ensure that the tower is fully supported during the lift.
Completed Derrick System – A View of the Tower
Here’s another view of the tower and Derrick prior to the lift. We supported the tower on a ladder to make the initial lifting easier. The ladder will also be needed on Field Day to allow our tri-band yagi to be installed on the tower prior to standing it up.
Capstan Winch Used To Lift Tower
There is a considerable amount of rope that needs to be pulled through several pulleys to lift the Tower/Derrick system. The pulleys provide mechanical advantage and slow the lift rate to a safe level. We used a heavy-duty gasoline powered capstan winch to pull the considerable length of rope required to lift our tower into the full upright position
Lifting The Tower
With our crew fully briefed on the process and safety procedures, it was time to lift our tower. The picture above shows the lift in progress. Our setup ensures that no one needs to be in the tower’s fall zone during the lift.
The Tower Is Up!
Here’s a picture of the tower after it was up and fully guyed. Our new heavy-duty Derrick system worked very well and lifting the tower was completed smoothly and safely with very modest effort.
The Nashua Area Radio Club Tower Test Team
After a few pictures, we took the tower down and disassembled it. We had quite a few members turn out to help us with our new tower test. Thank you to everyone who pitched in to make our third tower project a success! We are looking forward to using it during Field Day 2017!
Notice: falling derrick tower systems can be dangerous if they are not engineered, built and used properly by a well-trained team. The tower system described here is unique and is not a standard falling derrick system. Significant steps and material choices were taken to ensure the safe use of the system described here to put up our tower Time was spent to train the team who used the Derrick system to use it correctly and safely. We do not recommend the system here to others as the engineering, materials, and training required for its safe construction and use may not be readily available.
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 and the associated IT Test including –
Two Flex-6700 Software Defined Radios running over a network for our new Digital and enhanced GOTA Stations
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 Club 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 club member 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, Pierce, 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 decoders 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.
Scoreboard Computer
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 Club 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+ test bed 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 club’s 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 Club, we hope that the state of the art technology that we are using will generate interest among our visitors.
I wanted to share some information about our tracking our High Altitude Balloon as it flies. Our balloon will carry’s a GPS receiver and a 2m APRS Transmitter.
HAB Flight Platform
The on board APRS transmitter will operate on the Amateur Radio standard terrestrial APRS frequency of 144.390 MHz and will transmit our HAB’s position, heading, speed, altitude and other telemetry data every minute during the HAB’s flight. The transmitter is battery-powered and generates a 250 mW signal into a dipole antenna suspended from the HAB’s flight platform. The HAB will use N1FD-11 as its call sign.
Based upon online HAB flight prediction calculators that we have been using, we expect the HAB’s flight to last a little less than 2 1/2 hours. The HAB should reach an altitude of over 102,000 ft before the balloon bursts and the parachute on the flight platform brings it back to the ground at a safe speed. The above prediction will likely change as we get closer to an actual launch but most predictions have our HAB traveling approximately 100 km between its takeoff point and landing.
HAB APRS Packet Information
Aprs.fi will also store and display a copy of all of the APRS AX.25 packets transmitted by the HAB during its flight. Of particular interest to the STEM element of the flight will be the Balloon’s data on atmospheric temperature and pressure conditions at different altitudes.
All you need to track our HAB during its flight is Internet access and a web browser. Just click on one of the aprs.fi links here to see the HAB’s current location and altitude. If you have an APRS ground station, you may also be able to receive our HAB’s telemetry directly during the flight.
We need cloud cover which is less than 50% and ground wind speeds below 15 mph to launch our HAB. Will will post a final launch date and plans in the Youth Forum on our website. Our next possible launch window is on Saturday, June 3rd. We are all pulling for good weather so that we can launch!
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