Category Archives: Amateur Radio

Pictures by Radio

An amateur radio mode called Slow Scan TV (SSTV), given the speed of transmission, is really more about sending pictures than sending video. I’m guessing the name came from it’s similarity to how television video used to work.

SSTV picture of Castlemakers received using an app & ham radio.

I’ve used slow scan to receive images transmitted from the International Space Station as it passes overhead, which has been covered in a previous blog posting. At that time we recorded the transmitted ‘image’ using a voice recording app on a cell phone, emailed the image to a computer, and then used MMSTV to turn the recorded sound into an image. A more permanent/perhaps better setup would be using an interfacing cable to connect the radio directly to a PC with sound input.

Several months ago Ian stumbled across a simple phone app that decodes SSTV images, Robot36. It decodes the image directly on your phone, using the cell phone mic as input. After discovering a similar SSTV encoding app, SSTV Encoder, we realized we could send images directly to each other using our handheld amateur radios.

Closeup of our sign at night using a handheld radio to transmit the picture wirelessly.

Of course you should be able to use this setup with walkie talkies, FRS or even GMRS radios. We’ve used it over our local amateur radio repeater for even longer distances, and planning a demo with some of the other local amateur radio operators probably during Field Day in June.

We’ve started a webpage that explains SSTV and some of the software you can use to view it in more detail if you’re interested in trying it/learning more!

Slow Scan TV (SSTV)

SSTV is an amateur radio method of sending images using a transmitter and radio receiver that’s still in use today! The older transmission mode is not used a lot, but there have been some software improvements and updates that allow it’s use on devices other than PCs and you can occasionally hear it used with satellites and the International Space Station (ISS).

There are 2 programs we’ve used for transmitting and receiving SSTV transmissions: MMSSTV and YONIQ.
MMSTV is a very popular software program for amateur radio SSTV, but it is a pretty old windows program that hasn’t been updated since 2010. It still works however and what we first used for receiving transmissions from the International Space Station.
YONIQ is an update of the original MMSSTV which includes many improvements and many new features.
There are many other programs that will also receive and transmit SSTV images.

More recently we’ve been using our cell phones to decode/code SSTV images. If you’d like to experiment with that, so far we’ve tried Robot36 for decoding and SSTV Encoder for coding an image from your phone. Both are pretty simple applications, but seem to get the job done and convenient to use from your cell phone. We’ve got a blog post on our website that shows some example photos.

Last updated on 6/11/24.

Following Satellites

Last Saturday was Field Day for North American amateur radio, an annual ‘open house’ where 40k ham radio operators get out the radio equipment to make contacts and demonstrate to others how it’s done. We’ve helped out the local group PCAUXCOM the last few years by having a project to build or putting on an education session at their location.

Amateur Radio Satellite Tracker
This satellite tracker was built with 3D printed parts and components from Castlemakers.

Last year we did something on using WSPR with a Raspberry Pi, so for this year we talked about listening to amateur radio satellites and the International Space Station(ISS). Although we don’t currently have the equipment to transmit to a satellite, it’s not hard to listen with a handheld receiver or police scanner. We have hopes of someday acquiring the necessary equipment to be able to actually contact other amateur radio operators using one of the satellites, or one of the radios on the ISS.

We also showed off a prototype satellite tracker that Ian has been designing that was made with 3D printed parts from the makerspace. While it’s still a work-in-progress, the prototype uses data from a satellite tracking app to move a mounted antenna to follow the satellite as it passes the sky overhead. There wasn’t an ISS pass but Ian was able to show how it tracked another satellite during the presentation. The major components were designed in Tinkercad, the same program we use in our Intro to 3D Printing class, and the tracking hardware is moved by software running on a Pi Pico!

Listening to the International Space Station

A lot of people don’t realize that Amateur Radio can involve spacecraft, including the International Space Station (ISS). When it passes overhead, there’s a lot more than images you can receive!

When this blog post was written there were 7 astronauts aboard the ISS and several have an amateur radio license. There are 2 radios currently aboard and the astronauts will occasionally use them to contact people when passing overhead, although that is really pretty rare. But the radios are almost always in use, except during a spacewalk, from amateur radio operators sending radio signals up to the station which then repeats them back down to earth.

Set for receiving 2 channels at once, you can hear both voice and data audio from the International Space Station.

The ISS passes overhead an average of 5-6 times a day; anyone can track and predict when it will be passing over their exact location. You can even see the station passing by in the night time sky on a clear night. But what’s exciting to me, as the station passes overhead you can hear amateur radio operators sending voice and data traffic up to the ISS which then transmitted down to earth. That allows their signals to travel much further; I’ve easily picked up signals from Oklahoma and further with a handheld radio or scanner.

A couple of us at the makerspace are working on building an antenna to transmit up to the ISS. If you’re interested in learning more, stop by the makerspace during Open Shop time. And if the ISS is passing overhead, we can let you listen to the traffic yourself!

Radio Beacons

Circuit board & Raspberry Pi used for WSPR transmission.
Raspberry Pi Zero & circuit board Ian built for WSPR

There’s a lot of similarity between amateur radio (or ham radio) and ‘makers’ – in fact many people are involved in both. With the electronics workbench area that we added to the makerspace, there has been even more interest in amateur radio. Several months ago, we put a 2m/70cm member-donated antenna on the roof, then started looking for a transmitter/ receiver & more projects next.

WSPR signal reception graphic.
WSPR Signal reception reports from multiple continents using only 100 mW of power!
Antartica reception report.
Antartica reporting of an Indiana transmission!

A recent article(p30) on building a low power Weak Signal Propagation Reporter (WSPR) radio beacon using an Arduino had us wanting to make one. We have experience with single board computers & most of the parts at the makerspace already – so why not make one! But before I could get mine finished another member, who recently got his amateur radio license, redesigned the project using Raspberry Pi Zero and got his running in Crawfordsville!

Transmitting on less power than many wifi routers (100mW in this case), he’s had confirmation of his signal on the 20m frequency band in Australia, Denmark, off the coast of Africa, and even an Antartica research station! Stop by the makerspace – we’re glad to show off what we’re doing.

Slow Scan TV

This week the International Space Station (ISS) has been broadcasting images using Slow Scan TV (SSTV) from the Russian portion of the station on 145.800 MHz. It’s relatively easy to pick up the signal if you have the right equipment and can calculate the time it passes overhead correctly.

Audio from Tuesday’s ISS SSTV transmission over Greencastle Indiana.
SSTV image received from the International Space Station when passing over Greencastle.

This happens several times a year and will continue through at least June 26th, so we’re going to try receive and decode the image this coming Saturday morning at Open Shop. Overhead passes start 5:10 am, are about 90 minutes apart, and go through 1:22 pm local time. Stop by during our open hours from 9-12 am and you might get to see an image directly from the space station!

Building Antennas

coax cable antenna making
George (KB9RZQ) showing a finished antenna to the group.

For the June Castlemakers Kids meeting we built an emergency radio antenna out of coax cable.  Since it was ARRL’s Field Day, an annual ‘dust off the radios & get on the air’ event, we relocated our meeting to Putnam County’s Emergency Operations Center (EOC), where some local amateur radio operators were seeing how many radio contacts they could make. It also gave everyone a chance to see amateur radio operators making on air radio contacts and then try out the built antennas.

Testing a newly built antenna in the parking lot.
Testing a newly built antenna in the parking lot.

The design uses a short piece of coax cable with a connector on the end, you can see the instruction sheet we made and an example antenna. It’s a simple design that works quite well by cutting a different cable length for different transmission frequencies. Just strip the wire and twist the coax braid then you’re done. The antennas were then hooked up to a radio, and with a licensed radio operator supervision, they tried their antenna, some inside the building and others in the parking lot, to talk to each other.

Of course making antennas and watching radio operators ‘work the grid’ raised lots of questions. Thanks to George Edenfield (KB9RZK) and the rest of the PCAUXComm crew for hosting us. And special thanks to Dave Costin for giving us a behind the scenes tour of the Putnam County EOC – lot going on there many  don’t realize.

Learning with Hams…

Students learn about Amateur Radio Technician license privileges.
Students learn about Amateur Radio Technician license radio privileges and operating procedures.

Last night PCAUXCOM, the local Amateur Radio emergency communications group, began a FCC Amateur Radio operator’s license class at Castlemakers. It’s a great way to study for the test – although you can self-learn the material to get a license.

What they’re doing however embodies what often happens with vocations and hobbies – people practicing and learning with other people. Not only to learn quicker, but for enjoyment too. It can help make challenging things easier; in some cases even provide focus and accountability. In today’s noisy world with more opportunities than time that’s often difficult.

Makerspaces, and one of Castlemakers’ goals in particular, can bring communities of people together to share knowledge and skills by providing a space, events, equipment, and even just a reason for people to share something. Whether it be a CoderDojo (bringing kids and programmers together to explore programing languages), folks interested in 3D Printing (which also met last night to see printers in use at a high school classroom), or Amateur Radio operators and emergency volunteers assisting others to get a communications equipment operating license.

The PCAUXCOM class is meeting every Monday evenings from 6:30 to 8 pm at Castlemakers, it’s free and open to all, and still not too late to join in. They will also be offering a licensing test locally here in Greencastle just after the course is finished, contact George Edenfield for more information.

Amateur Radio Convention

Dayton Hamvention Slow Scan Video Transmission from Balloon at 1000 feet
Dayton Hamvention Slow Scan Video Transmission from Balloon at 1000 feet

It’s that time of year again when amateur radio operators, descend upon Dayton, Ohio for the annual Hamvention. This weekend (May 15-17th) in and around Hara Arena 25,000 people or so will be there to learn things at seminars, buy, and swap things. This is the biggest event in the Midwest for folks interested in making anything electronic – although the focus of the event is on amateur radio. But if you’re interested in making things, especially electronics, someone will be there selling what you need (or what you want!). I’ve seen everything from electronic kits to build almost anything to Geiger counters, it’s an amazing gawkfest that even includes some military surplus (I remember the collapsible towers were a big item, literally, several years ago).

While you’re there it may be worth a stop at Mendelson’s Surplus in downtown Dayton to check out the 6 floors of surplus ‘stuff’ in their main building (their website doesn’t do the place justice). And of course the USAF Air Force Museum, which I’ve written about earlier, is a great stop to make it an awesome STEM weekend – that’s worth a trip on it’s own.

This Friday we’ll be doing a 3D printer demo for a class at Tzouanakis intermediate school in Greencastle to show them how math is used in making 3D models and prints.  Will also be bringing the Printrbot printer to our next general Castlemakers meeting, which is being set up for late May.

Dayton Hamvention

Dayton Hamvention Slow Scan Video Transmission from Balloon at 1000 feet
Dayton Hamvention Slow Scan Video Transmission from Balloon at 1000 feet.

Next weekend (5/16-18) in Dayton Ohio will be the annual Dayton Hamvention. With about 25,000 people attending that are interested in building ‘stuff’ and over 2000 outside flea market spaces (never mind all the indoor commercial vendors there) it is truly an amazing event for makers. This year’s theme even reflects that – “Makers… the future of Ham Radio.”

Many people when they hear about Amateur Radio (or Ham Radio) Operator imagine an elderly guy with a green visor hunched over a telegraph key. Matter of fact several years ago Jay Leno pitted teenagers using a cellphone against some amateur radio operators using morse code to see who was fastest at sending a message (the ham radio operators won).

Amateur radio these days is far from that doing everything from building and launching satellites, providing emergency communications during catastrophic and public events, bouncing signals off the moon to talk with other ham radio operators and much, much more. Many of our astronauts are ham operators and use the amateur radio station in the International Space Station to talk to classrooms. There was a group when I was in Terre Haute that was trying to put together a classroom broadcast to the space station -I’ve often thought that it would be a good educational experience for kids in Putnam county to talk live to an astronaut in space.

If you’re interested in finding out more about amateur radio in Putnam County, George Edenfield (KB9RZK) would be a good person to contact. He’s the IT person at Putnam County Public Library & you can reach him at 765.653.5327. I’m not longer ‘radio-active’ but still have my license and use the skills in electronics/home-brew projects/fabricating things that I learned as an amateur radio operator. Or head over to Dayton next weekend and gawk to learn more. If you’ve never been you’ll definitely be impressed. – Chris (N9VFD)