Articles and Information related to Digital Modes. Topics include PSK, RTTY, JT Modes, APRS, operating using Digital Modes, equipment, software, and more.
The ARRL Rookie Roundup RTTY contest is open to anyone who was first licensed in 2015, 2016 or 2017 or anyone who has never made a RTTY mode contact.
We will be defending our title as #1 Multi-Op Area 1 in the ARRL Rookie Roundup – RTTY. The contest will take place on August 20 from 2 pm – 8 pm and we will operate from AB1OC/AB1QB’s QTH.
This is a great opportunity for you to try out digital modes or to try your hand at contesting!
Abby, AB1BY and Jamey, KC1FFX operate during the 2016 Rookie Roundup RTTY
Please contact Anita at [email protected] if you are interested and for more details, see the calendar event.
Students, Teachers and Club Members came out to be part of the launch and to track our HAB. The first step was to move all of our gear to the center of the athletic fields at the school and organize all of our equipment.
Flight Platform Final Assembly and Test
Next, we attached the GoPro video cameras, satellite tracker and the battery pack for the Flight Computer and 2M APRS transmitter to the flight platform. We used an APRS capable HT to confirm that the flight computer and APRS transmitter were working.
Rigging the Flight Line
We rigged the 40 ft. flight line which connected the HAB’s flight platform, recovery parachute, and the balloon.
Balloon Inflation
And then came the inflation of the balloon from the Helium tank. The winds were gusting to about 12 mph at this point which made inflating the balloon a little tricky. When filled, the balloon was about 6 ft. in diameter on the ground.
Launch!
With both GoPro cameras running on the flight platform, we were ready to launch. A 10-second countdown and the balloon was up and away!
Tracking the HAB
We watched the balloon from the ground as it soared off into the clouds. The 2M APRS tracking system worked perfectly and we spent the next several hours at the launch site, at lunch, and in our cars tracking the HAB on aprs.fi.
HAB’s Flight Path On APRS.fi
Our HAB’s flight path took it across Massachusetts where it reached a maximum altitude of 91,700 ft. above sea level (ASL).
Looking Upward at the Balloon (Near Burst)
The balloon reached a diameter of approximately 30 ft before it burst. After the balloon burst, the parachute deployed and the payload descended to a landing in the northeast corner of Rhode Island.
HAB at Recovery Site in Rhode Island
A combination of the APRS transmitter data and the onboard sounder allowed the landing location to be pinpointed and the flight platform recovered with help from a local resident.
The onboard GoPro video cameras captured some awesome video during our HAB’s ascent! All of the media captured by everyone who participated in the launch as well as the APRS data allowed us to produce the video above. Turn up your speakers and give it a play in full-screen mode to enjoy the experience what we shared!
By the time we had launched, the school year was at an end so we will have to wait until the fall to work with the students and teachers who were part of our STEM project to analyze the data from the flight. All in all, our HAB project has been an amazing experience for all involved. We are planning another HAB STEM experience and launch with additional schools in the fall.
We want to especially thank all of our donors whose generous contributions made this project possible.
We’ve been thinking about building a portable Go Kit for VHF/UHF Emergency Communications (EMCOM) and Field Day Applications for a while now. The following is a list of our requirements for a Go Kit –
2m and 70cm operation with FM simplex and repeaters
APRS capability and tactical display for portable coordination
The heart of any Go Kit 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 Go Kit application.
AvMap GeoSat 6 APRS Tactical Display
We have been using the Kenwood TM-D710 along with an AvMap GeoSat APRS display in our APRS iGate setup and the combination works very well. The AvMap display lets one see the location of portable and mobile APRS stations on a map display. This arrangement is perfect for coordinating activities in an EMCOM situation. The AvMap GeoSat 6 APRS display is no longer in production but I was able to locate a nearly new unit on eBay.
EMCOM Go Kit Packaging
iPortable Enclosure
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 Go Kit 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.
EMCOM Go Kit Construction
Radio Shelf
With all the components in hand, we began the construction of our Go Kit. 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 were 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 charging 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.
Backup Battery
The PWRgate was configured to properly charge our 18AH AGM backup battery. Note the use of a fuse in series with the battery for safety reasons. We used a Powerwerx SPS-30DM adjustable power supply set to 14.5Vdc to operate our Go Kit and to provide the proper charging voltage for our AGM battery.
EMCOM Go Kit Operation
Diamond X-30 Antenna and Mast
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 a 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.
Finished Go Kit In Use
The picture above shows the completed Go Kit 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.
Go Kit Packaged for Transport
The Go Kit 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 Go Kit during our club’s weekly repeater net and it worked great. The first real use of our new Go Kit 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.
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