Category Archives: Featured

This category is for featured articles that we want to include in the sidebars and other areas on our website.

Hudson Memorial School Preparations for the ARISS Contact

Things are now moving full speed as ahead as we quickly close in on our Amateur Radio contact with the International Space Station.  While preparing for this contact began over a year ago the rush is now on to complete the last pieces required to create a successful contact.  Teachers and students from grades 5 – 8 are working through space and radio curriculum applications, preparing questions for the astronauts, and excitedly waiting to hear about our official ISS contact time.

Preparation for the contact began over a year ago with the ARISS application process.  This is the process which brought my school and me into the amazing world of Amateur Radio.  The application asked us to prove that we provided several opportunities for our students to access curriculum centered around the concepts of radio and space sciences.  In our application, I was able to include that our 6th-grade science curriculum covered space, our 8th-grade science curriculum covered radio communications, we annually hold an Astronomy and STEM night for all students, and our 7th-grade team already provided a skype contact with a NASA Engineer after their Science Fiction unit.  We have since included new opportunities for students to access space and radio sciences by participating in a High Altitude Balloon launch, planting seeds that were brought to the International Space Station, visiting the Boston Museum of Science for the special exhibit on space and the international space station, building rovers and participating in an egg drop, having our pre-engineering program work on solutions for the ISS, and building amateur radio into our annual STEM nights.

One of the best parts of working toward this contact has been the relationship that has been forged with the Nashua Area Radio Society.  The application suggested that we reach out and partner with a local radio club.  I believe we lucked out being located just across the bridge from NARS and that there are so many members dedicated to helping students discover Amateur Radio.  Without this relationship, this contact would never have been possible.  This relationship provided us with the ability to expose students to Amateur Radio through a comprehensive curriculum with the High-Altitude Balloon Launch, chances for students to get on the air at our annual STEM night and through our hosting of their ARRL Field Day activities.  We have also been able to work to provide student amateur radio licensing in our first school licensing course and our new school radio club.

In just the past few weeks preparation has accelerated as we near our possible contact dates.  Students and teachers from the 5th through 8th grade worked on questions to ask the astronauts.  Staff was provided with previously asked questions and links to NASA and ISS research.  In just a few short weeks questions rolled in from the students at all levels.  Teachers that teach ELA, Social Studies, Math, Science, PLTW, and 5th grade were invested in helping students developing thoughtful questions.  In the end, we had a stack of over 300 questions to chose from.  Students questions ranged from inquiries about science experiments to how the ISS provides clean air for the astronauts to breath.  It was an incredibly difficult process to narrow down the questions to twenty-three and then to select the fourteen students that would ask questions.  One might ask why we only went with fourteen students.  The answer is simply that with a ten-minute contact window, we wanted to make sure that every student asking questions would get a chance to talk to the astronauts before the end of the contact.  While there are twenty-three prepared questions that include entries from other anonymous students, we wanted to make sure every direct participant had this once in a lifetime experience and did not get left out because the pass ends before they asked their question.

Along with questions, we have had to provide a story about our local school to the ARISS people as a bio of our school population.  We are working now on a media press release that will be sent to WMUR, Hudson Cable Television, the Nashua Telegraph, and the Hudson Litchfield News as soon as we have our final contact date.  We are working with the students that are selected to go over how to ask their questions, what the set-up will look like on the day of the contact, and how close to the microphone they need to be to make sure their question is heard.  We are also working on how and what additional programming we will present to the school during the week of the contact and during the thirty minutes before the preparation.

It still amazes me how much our staff and students have learned about amateur radio and the ISS in just one year.  I know that I myself have grown immensely in my knowledge and understanding of a hobby and interest that I knew nothing about just two summers ago.  My one hope for my students after this contact is that we inspire more students to take an interest in science, space, the ISS, and amateur radio.   Who knows, maybe someday we will be contacting someone in space who sat in our auditorium during our ARISS contact.

A sincere thank you to everyone at the school and members of the Nashua Area Radio Society that are working so hard to make sure that our students get to experience this once in a lifetime event.  Your efforts are noticed and greatly appreciated.

Dan, AC1EN

FT8 and Ghost Decodes

The FT8 digital mode that Joe, K1JT, and company rolled out a little over a year ago has become a game changer in ham radio. The mode is a modification of the JT9 & JT65 weak-signal modes that have been around for nearly ten years, an eternity in the digital world. These modes, while great for modest stations (read: apartment and condo dwellers; CC&R prisoners; and those with an iron-willed spouse who does not like antennas), suffered from a SLLOOOW exchange cycle. A rapid QSO with a signal report, acknowledgment and 73 might make it in four minutes. FT8 cuts the time to less than half that. The migration to FT8 has left the JT9 & JT65 band segments virtually deserted today.

The burgeoning success of FT8 has led to the development of a DXpedition mode that uses a “fox and the hound” model with the DX being the “fox” and the rest of the world being the “hounds”. The mode enables the DX station to transmit simultaneously in up to five slots at the low end of the FT8 band segment and work hounds operating in the rest of the segment, racking up several hundred QSOs/hour. Still another version is in beta testing that will be used for the RTTY Roundup contest in a couple months. Support for Field Day 2019 is just around the corner.

I’ve found FT8 a great way to keep chasing DX that I just cannot hear on CW let alone SSB. I’ve amassed 1300 QSOs to date and over 140 countries which says a lot with the disappearance of sunspots. All this time watching calls scroll by has given me a chance to observe operating habits good and bad. Good operating is being able to call a DX station off-frequency to increase the probability of being decoded. Bad operating practice is cranking up the power to spill over into another slot and even desense the station you are trying to decode.

Recently, I noticed a strange phenomenon from stations presumably running high power. Signals in FT8 usually have a received level from -2 to -22 dB that is adequate for decoding. Strong signals such as local stations or stations in the first skip zone with levels of 0 to +5 dB obviously are not hard to decode. However, I’ve seen some stations with a received signal level of +4 to +15 dB or more have a second decoded slot with a signal level of -13 dB or lower. Furthermore, this second decoded slot is always 120 Hz below the primary decoded slot.

I first noticed this behavior with a local station. I sent him an email wondering if his sound card went south and he was experiencing some kind of digital splattering. He was surprised that his ICOM 7610 would create a messy signal and insisted that everything checked out OK. A few days later, he sent me an email with a screen capture of another station in The Villages showing the same behavior. This led to the three of us batting around possible causes. Excessive power due to proximity was one possibility in spite of our lack of an aluminum forest. Another suggestion was to try another computer, the thought being that a dated machine would be a bit over-worked at decoding and “bit-draggled” in the presence of strong signals. One fellow switched to a laptop and saw the same thing so nix the computer. The 120 Hz separation made me wonder if power regulation went haywire but then everything in town would have gone south.

One night on 30 meters I logged ten stations that showed these “ghost” decodes. The station locations ranged from IL, IN, KY, PA/NJ and VA based on their grid squares. All of the stations showed a received signal level greater than +4 dB. Another odd thing was the tendency for the ghost decode to occur only during a CQ. When the station was in a QSO, I did not see the ghost. In addition, received levels often fluctuated as much as 12 dB while in a QSO. Like a real ghost, the secondary decode does not consistently appear for any strong station I happen to find.

For the record, I have an Elecraft K3 with the K3S synthesizer upgrade. My antenna is a multiband Hygain 6BTV vertical that has a gain of 3 dB over a wet noodle. I set my RF gain around 25% to avoid clipping received signals. Not a hyper-sensitive setup; just your average CC&R station.

Since FT8 is driven by a computer, I decided to subscribe to the WSJT-X reflector to post what I observed and inquire if anyone else had seen the phenomenon. I figured most FT8 users would be far more bit-savvy than I am and might have an idea what is happening. I have not had any bites after several weeks as to what it might be.

As I pondered over this oddity, I came back to the Fox/Hound version of FT8. Each slot that the fox uses is adjacent to the next one. The FT8 software juggles a response to a hound such that the hound is automatically switched to the fox’s transmit slot to complete the QSO. I view it kind of like the carnival kid’s game of fishing for a specific duck in a tub full of rubber ducks circling around. He hooks the duck and pulls it out to try for another one. In a sense, this is similar to the multiple receiver windows that a software-defined radio can implement.

So, where does this leave me? Simple answer: stumped. Therefore, I am inviting those in the NARS community who have experience with FT8 or any of the WSJT-X modes to open up the FT8 program and see if the ghosts appear and look for some common cause.

Disclaimer: Any correlation between occurrences of this phenomenon and October 31 is purely coincidental.

Ed, K2TE

ISS Crew Contact Part 1 – Ground Station Design and Construction

Our planned ISS Crew Contact is almost here! It will take place sometime during the first week of December (December 3rd – 8th) and we are busy finalizing our Ground Station and preparing for our contact. The link below is the first in a series of articles that are planned to describe steps in this project and the actual contact experience. The first article explains the Design, Construction, and Testing of the two Ground Stations that are required as well as plans for connecting them to the Audio-Video and Data systems at the school.

Source: ISS Crew Contact Part 1 – Ground Station Design and Construction

Fred, AB1OC

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