SDR Top 10 Has Fallen: Meet something new....

 

At the HOPE 16 conference back in August 2025, my presentation focused on the most popular projects based on key search terms such as "SDR", "Software Defined Radio", "Amateur Radio" and "Ham Radio".   

My theory was to look at how many stars were voted on by the GitHub community per project and compare against how long the project has been around in order to create a velocity score, simply by dividing stars by number of days old the project is.  While Git is just one narrow dimensional lens to observe through, it is still a good one since its a great way to capture crowd sourced ranking data.

The idea was that the faster a project could generate the most stars would mean that it captured more interest or maintained that over time and thus, would be very important to pay attention to these projects. So while not perfect, this is the best way to capture interest level from a community of people who generally all have overlapping interests.

Here are the slides, charts and data to back up the presentation if you missed it. I analyzed the top 10 most popular for each search term for a total of 40 projects overall. Below is an example of one of my "velocity" charts enabled by the star history site which can be used for exactly what I needed.

I really wanted to wait a full year before seeing if there were major changes to the top projects, so here is a short update to start May 2026 off since too many exciting things are happening. I will compare again just before HOPE 26 at the New Yorker Hotel now less than 90 days away.

Changes:  SDR

First up, lets look at the "SDR" top 10 from last year and how they compare to now. I bolded out four worth talking about below.

Last year, GQRX which is one of the longest maintained "SDR" projects was the 9th most starred project followed by SDRangel as 10th most popular. Less than a year later, GQRX has dropped to 13th most popular and SDRangel is now 11th most popular. 

In March, SDRangel released version 7.24.0 which now includes Meshtastic functionality,  which is clear evolution from the earlier Chirp Chat function designed to support LoRa based messaging.  This is nice because if you have a HackRF, ADLAM Pluto, Lime SDR or most other transmit capable SDR, you can use it as a mesh device with limited capabilities along with its many (many) other useful features.

Not much of anything has changed in the last year however with GQRX since its intent was always to be a simple and easy to use radio application for those getting started with SDR.

Shadowbroker

What is really amazing are the two new entries to the top ten most starred SDR projects less than a year later from my original analysis.  

Shadowbroker is defined as "Open-source intelligence for the global theater. Track everything from the corporate/private jets of the wealthy, and spy satellites, to seismic events in one unified interface. The knowledge is available to all but rarely aggregated in the open, until now." This project is now the 6th most popular as voted on by the community all time. 

Much of what Shadowbroker offers is functionality built into SDRangel actually, but Shadowbroker is meant to be an OSINT tool where SDRangel is more of a SIGINT tool, with built in OSINT functionality. 

It is amazing how fast Shadowbroker has obtained 5,500 stars since its first release which was only in March 2026.  From Shadowbroker's repository, here is a video showing its capability. 

A blend of true coding plus some level of "AI" vibe coding was used to come up with this and is an amazing achievement that not many are talking about Shadowbroker across the wider interwebs.  Maybe that will change soon. I sure hope so. 

It is really worth explaining why Shadowbroker is unique.  While SDRangel allows the user to show many types of location based signals like aircraft, balloons, boats, spacecraft, amateur radio people and more on a map all at the same time from directly connected SDR's, or those over a network,  SDRangel also allows some of what is received to also feed into other systems.

Shadowbroker is not just about radio signals. Its about complex situational awareness, so this is a really cool project for looking at many types of information. If you ever dreamed about becoming the "guy in the chair" this project helps you get pretty close to that, just like in the movies!.

Ground Station

Having a look at the now 9th most popular repository simply called ground-station, this project began life in October 2025 and has already gained 4,200 stars.  This is also very impressive as it touts being  a full-featured, open-source software solution for satellite tracking and radio communication. 

Designed for amateur radio operators, satellite enthusiasts, and researchers, it provides a comprehensive and easy-to-use platform for monitoring spacecraft, controlling radio equipment, and receiving live radio signals from satellites. This project was built with the help of Claude Code and Codex.

It is clear what this project is and how it was made.  Again, much of this functionality is built in to SDRangel, but can be overwhelming to some users and the new ground station project seems really nicely done.  A full understanding of its functionality can be found on the project page, which is now coming close to its hundredth release yet is still on up to version 0.4.4.  

Typically, when a project hits the v1 milestone, its considered much more mature, so there is certainly a lot more expected to happen with ground station.

Software Defined Radio

Comparing the top 10 from last year until now,  the same are all present with a few changing places in total stars, but otherwise nothing else is unique.  Clearly if you want to experiment with SDR,  its worth searching both ways, but the long form of "software defined radio" is not where things are happening compared to "SDR".

Ham Radio

There is one change in the top ten thanks to a project called HamDashboard which now would rank as 9th most popular and surprisingly helped knock down the LoRaHam project down to the eleventh spot. While the LoRaHam project is managed by the pretty famous Travis Goodspeed, here is a clear example that when a project sees no updates, it often becomes less popular. 

But, the work of Travis on areas like hacking the TYT MD-380 which helped make DMR very popular and his other projects found on his Git repository demonstrate that its worth keeping an eye on anything he is doing.  

HamDashboard by VA3HDL started three years ago, but has seen more work in the last few months. The focus is to provide a simple, browser-based ham radio dashboard that displays images, maps, web pages, and feeds in a configurable grid. It is lightweight, easy to host, and suitable for use on a local computer, Raspberry Pi, or a static host such as GitHub Pages or Cloudflare Pages. 

With projects like HamClock undergoing changes, it seems HamDashboard is becoming more popular and here is the proof to show that.  While very different than what Shadowbroker does, it seems that a need to visualize many data sources is an area that many radio hobbyists are very interested in. 

Amateur Radio

The top ten most "starred" projects found by using the "amateur radio" key term are also almost the same as a year ago.  A few projects changed total rankings, but there is a new number nine present via the APRS D project, which has been around since 2021, but only recently become more popular. 

Many changes within MKISS and AX.25 are starting to rattle thanks to the recent news about certain things being dropped from the Linux kernel but that is out of scope for this update, but still was worth a quick mention.

APRS which has been covered here at length continues to be a misunderstood or narrowly conceptualized area within communications, so its amazing that this project is one of the more popular voted on projects to keep an eye on.  

Pretty much anything related to APRS is worth keeping an eye on actually, so this is a nice place to end this article without diving super deep on this topic.

Summary

It is important to embrace the advances in technology and a great way to do that is to spend some time searching for things on Git.  The value I hope my presentation offers from last year and into this update is to demonstrate theory to fact in order to prove a point on how to track trends and uncover hidden patterns around topical areas worth paying attention to.  

A benefit for those interested in coding is you may find something you can help improve or for those not considered "coders", might find inspiration to leverage artificial intelligence (AI) by way of vibe coding to help create solutions targeted at clear problems, just like Ground Station has done and most likely a few other projects too.

Also worth noting that when it comes to "amateur/ham" radio, there is still not enough excitement in these areas to attract more innovation.  While unfair to compare to "SDR",  this is an area which many in the amateur community should be looking at for what should be next.

FCC Update: Yaesu FT-3 cleared for launch

On May 26th 2019, the Yaesu FT-3 radio received the FCC ID of K6620725X20. This covers both the radio itself and also the Bluetooth module for hands free operation and possibly other functions too.

Based on news from Yaesu at the 2019 Hamvention, they expect this radio to be available in the June 2019 time frame. It is common with the FCC while requesting an FCC ID to provide test data along with pre-release copy of device photos and instruction manuals.

The above detail found on the FCC OET website shows that a date of July 10th is when this material will be made available to the public through the FCC.

This latest digital voice radio for the amateur community will incorporate Yaesu Fusion C4FM alongside analog FM and AX.25 packet communication. The FT-3 will replace the FT-2 as the flagship handheld radio offered by Yaesu and will compete with the D-Star capable Kenwood TH-D74 for current "most expensive" amateur handheld radio.

HVDN will likely provide a side by side review of the FT-3 against the TH-D74, so be sure to check back later this summer.

The big questions so far are:

• Will the FT-3's dual receiver have desense on receive while operating FM satellites?

• Will the FT-3 allow for Falconsat3 APRS split band 9600 baud?

• How well will the audio record function work?

• Will it be possible to wirelessly pair the radio to a computer for programming like the Kenwood?

• Would AM mode reception be possible in the military aircraft band?

• How easy will it be to program by hand?

• Will the spectrum scope be useful of a novelty?

• Are some of the new Fusion features reminiscent of various 1990 era analog radios?

Sign up for updates below or send in your own questions in the comment section or the Facebook group for this radio.

Presentation: Satellite Spectrum & Amateur Radio

Steve K2GOG presented on "Satellite Spectrum & Amateur Radio" at the Trenton Computer Festival on March 23rd alongside another 50+ technology and innovation focused topics.

The goal of the presentation was to cover the valuable radio spectrum available through amateur radio and promote its use through innovative communication applications on earth and in space thanks to underlying computer technology

How much spectrum do we have?

For those that are already licensed amateur radio operators, you may have a printed version of the below spectrum chart that the ARRL publishes or at least have seen it somewhere before.

In the United States and most other countries, there are different license classes of amateur radio operators. Some countries restrict the transmit power or operating modes as well as what frequencies can be used depending on your license restrictions.

Steve decided to add up all the spectrum that is accessible to the three current United States amateur radio licenses and further highlight just how much of the total 1.4 GHz of total discontinuous spectrum can be used for satellite related communications. The results are pretty interesting.

What really separates the Extra from General or Technician?

Sometimes it is good to be simple. Get the highest license possible and ensure you never have to worry about operating on the wrong frequency. Currently, the only thing that separates the highest from the lowest license class in terms of spectrum access is 3.9321 MHz of operating capability.

The difference in spectrum for the different license classes is mostly found in the HF bands ranging from as low as 135.7 kHz and up to 29.7 MHz. The only other spectrum not accessible to the technician class license is the 219 to 220 MHz portion of the under utilized 1.25m which many consider as being only from 222 to 225 MHz.

The remaining spectrum is all available to the Technician class license holder!

What if your not interested in long range "HF" communication?

With advances in radio receiver sensitivity and advanced low signal to noise ratio transmission modes, large antennas often associated with HF operation are not always needed.

However, even with specialized magnetic loop antennas and FT-8 digital text modes -nothing beats a full sized dipole for global communications on the 14 MHz or 7 MHz bands often referred to as 20m and 40m respectively and not everyone has the space or interest in such an antenna.

Radio propagation theory does not always guarantee communications are possible at all times of the day which may frustrate some people who only have limited times to "play radio" with HF spectrum.

RF HF propagation is just like the weather

A forecast is still just a forecast and is generally correct, but the difference between satellite communications and HF is the predictability.  For those with limited time to gain "radio communications" gratification, satellite communications may be worth a look.

You can easily calculate when a satellite will pass over head in the case of the "Low Earth Orbit" satellites covered in Steve's presentation for example. It certainly would be great if the weather was like that, wouldn't it?

Depending on satellites

One shortcoming of most satellite communications is that you are reliant upon a man made piece of technology flying over your location in order to make long range contact.

The other shortcoming is you can only make contact with other stations in the footprint of the satellite, which is different than HF since technically you can talk around the world and sometimes even hear your own echo under the right conditions.

Benefits of satellite communication is that you can get a lot of "ham radio" done in a very short amount of time given the brevity of low earth orbit satellites for those not fortunate to live in the foot print of the only current geosynchronous satellite that covers all of Europe, Middle East, Africa, India and a few other countries across Asia.

Fight:  Innovation in amateur radio

The first amateur satellite put into orbit was OSCAR-1 in 1961, just 4 years after Sputnik was put into orbit as the first ever satellite. 

Now almost 60 years later, there has been a total of over 100 satellites put into orbit and most of them being fully operational, with a few example success stories being AO-7, SO-50, AO-92 and QO-100.

In total and thanks to international regulatory efforts, all this satellite success requires spectrum to be set aside since managing who or what can use certain frequencies is more challenging compared to how a specific country can manage its finite spectrum resources.

Its pretty clear that there has been a lot of innovation within the amateur radio satellite spectrum, but much of it has yet to be fully realized.

One example of how technology originally meant for meteor scatter or earth-moon-earth communications which involves bouncing signals off of these non-man made satellites is known as low signal to noise ratio modes, mostly invented by Joe Taylor, K1JT.  The modes can now be found in use on the HF bands rather than for space related contacts. Here is how computers and amateur radio together create innovation.

Technology Improvements: We all benefit 

OSCAR 100 which was put into functional orbit by the Qatar Amateur Radio Society along with technical guidance from the German branch of the Amateur Satellite Corporation known as AMSAT pushes the boundaries of technology and spectrum management.

In 2018, various digital voice modes such as those enabled and made more accessible due to Multi Mode Digital Voice Modem (MMDVM) hot spot devices created an issue for certain satellites operating in the congested 435 to 438 MHz band.   A LEO satellite such as AO-92 speeds overhead at an average altitude of 220 miles and can easily be interfered with by 20mW hot spots and the lower power radios people use to access them. OSCAR 100 is the only satellite that does not have this issue.

Price has driven the adoption of MMDVM hot spots and radios such as the Anytone D868, TYT MD-380 and others. 

Today, thanks to the QO-100 satellite, there is a lot of rapid innovation taking place which shows that cost and user benefits generate lots of excitement that highlights the growth of the radio arts as specified in FCC Part 97.1.

The only unfortunate thing for North American amateur radio operators is that its not possible to utilize this innovative satellite and its great use of spectrum because it is in geosynchronous orbit. However, the AMSAT project GOLF is coming near which is exciting!

Looking beyond, satellite is just one way to show innovation through the use of spectrum. The future of amateur radio is dependent on finding other innovative applications for spectrum, so why not look at what else may be possible outside of the HF bands, even going as high as the mmW bands -
GigaHertz.... not MegaHertz!!!

Full Presentation & Added Bonus

The complete, but non-animated version of the presentation can be found at the link below in addition to the amateur spectrum database compiled to help develop some of the content Steve K2GOG presented both at the HVDN Quarterly meeting this past March 11th as well as TCF on March 23rd.

HVDN Satellite Spectrum Presentation

How was it? February HVDN Meeting

Even with all the snow, ice, sub-zero temperatures and sporadic unseasonably warm winter weather, it was possible for just over 20 people to venture out on March 11th and take part in the first Hudson Valley Digital Network meeting of 2019.

What was on the agenda?

Our meeting inspired both the local maker community and national level of amateur radio leadership to have representation that illustrated first hand what amateur radio is all about as created by the Federal Communications Commission almost 100 years ago!

Because amateur radio is a federally licensed service, we have our own unique set of rules to follow. Part 97.1 of the FCC rules found in many places such as government, lobbyist and even legal academic websites such as New York's own Cornell Law School.  

From the over 21,000 MHz of discontinuous wireless spectrum we are provided to the equipment, power levels and information we are allowed to transmit - there is so much that amateur radio can offer a wide range of hobbyists that goes unnoticed at times today.

The major draw of the evening in Rhinebeck New York at the ultra modern co-working space aptly named CO. were our two presenters. Sean Swehla of the Squidwrench maker group and rarest of rare contacts to ever make through "on the air" methods, talked about the upcoming (and nearly sold out!)  Build It: Oscilloscope & Signal Source event taking place on March 9th.

This upcoming event focuses on education about soldering and how many hobbyist groups can benefit through education of practical use of basic or advanced test equipment.

STEM & Amateur Radio Together?

In comparison, our other presenter was Ria Jairam spends much more time making use of the wireless amateur radio spectrum compared to Sean who also holds an amateur radio license but they both have different yet similar hobby interests which is one thing that makes amateur radio great!

Ria holds the distinction of being the newly elected Hudson Division Director of the Amateur Radio Relay League provided a great presentation and insight as to the priorities of the ARRL at the highest levels including renewed focus around Science, Technology, Engineering & Math.

She also highlighted the new executive leadership of the ARRL and experiences that will help ensure that amateur radio principles are made more visible to wider audiences. Ria also highlighted the newly improved and expanded Hudson Division website and its activity calendar.

The Future Of Amateur Radio

The organizers and presenters of the meeting all agreed that the future of amateur radio is under attack if we as a community do not promote modern and relevant aspects of the hobby in an overly connected world we have come to know today. 

The attending audience seemed to be in agreement and following the presentations during refreshments were many discussions covering topics including some of the following:

• DMR University (Details shared in person by Len N2LEN at the meeting too!)
• Satellite communications
• Electronically steerable antenna
• Upcoming Trenton Computer Festival  (Thanks Joe N1JTA & Steve K2GOG)
• What is the Circle of HOPE? (Thanks Joe NZ2E)

The next HVDN meeting will be on March 11th at 6:00 PM in Rhinebeck with location details at https://hvdn.org/meeting . Featured March discussions will likely include:

• Sneak preview of Steve K2GOG's satellite spectrum presentation and live demonstration of SATCOM

• Oscilloscope use cases based on the DSO150 scope and signal source constructed at Build It two days prior.

• Special guest speaker and topic 

Anyone interested in suggesting future presentation topics or contributing in some other way (snacks, prizes, etc) for the future meetings, please contact HVDN at info <at> hvdn <dot> org

March 23rd: TCF19 Computer Festival

This event has a little something for everyone interested in modern technology and applications, not just related to amateur radio or even computers.

The featured keynote this year will be led by Tony Sager of the Center For Internet Security which is headquartered just outside Albany, New York.  Tony will talk about the importance of cyber-security and how it affects almost every aspect of our connected lives today.

Other featured presentations include:

• The State of Cyber Crime in New Jersey by NJ Department of Homeland Security Cyber Team!

• Maintaining the Integrity of Elections in a Digital World – Rebecca Mercuri

• Quantum Computing – Barry Burd 

• Amateur Radio Satellite Spectrum - Steve Bossert 

• WordPress Bootcamp – Lou Judice

• Cybercrime and Theremin Zen – Kip Rosser 

• MMDVM Hotspot Construction - Joe Apuzzo  

• Hands-on Arduino Workshop for Beginners – Katalin Frolio

• All Day Robotics Pavilion – Seung-yun Kim

What about amateur radio? 

HVDN's very own Joe Apuzzo N1JTA and Steve Bossert K2GOG will be among the 50+ presentations and workshops also taking place during this fantastic event.

In N1JTA's 30 minute presentation he will talk about how radio and computers has converged through the popularity of digital modes in Amateur radio and how it has grown exponentially over the last few years due to the affordability of VHF/UHF digital handheld radios and other equipment.

One of many MMDVM hot spot options, the N2BOC version 

is full duplex capable and the same size as a Raspberry Pi Zero. 

A large part of this growth can also be attributed to the impact of hot spot devices and the unique learning capability they create. A hot spot is a small access point type device that uses amateur radio spectrum and a decentralized network of servers to enable global or local  digital communication.

Joe will cover at a high level, what is needed to construct your own "micro repeater" or hot spot device and how it works, along with how to create secure connections and utilize a decentralized network maintained by a group of amateur radio operators around the world.

Brandmeister is unique in that it can route all types of digital voice traffic through its decentralized network of servers to end node devices such as hotspots and repeaters

Since the hot spot device is nothing more than a Raspberry Pi single board computer and a multi mode digital voice modem hat plus some open source software called Pi-Star it is relatively inexpensive but very complex to understand how it works.

Steve will be cover in varying detail more than 21,000 MHz of spectrum available to amateur radio operators looking to experiment with satellite communications today. While much of this spectrum is above 1.2 GHz, this still leaves over 60 MHz of varied spectrum that can be used by those holding the easiest to get Technician class amateur radio license and with minimal expense.

Your DMR radio can also be used for satellite communications
via analog FM mode you might have forgot exists.

Steve's discussion will cover the most common spectrum used today for amateur radio operators interested in satellite communications, additional spectrum users to be mindful of and a review of the most active satellites that can be used with less than $100 of invested equipment.  He will also give a "sneak peak" on this topic to attendees of the March 11th HVDN meeting in Rhinebeck, NY.

More about TCF19, the full agenda and when is Joe's presentation can be found at https://tcf-nj.org/

Interested in other interesting events? Check out the HVDN activity calendar

Survey Results: U.S. 2018 70cm Band Spectrum

A poll concerning the use of 420 to 450 MHz spectrum in the United States was posted on the popular QRZ.com website on August 29th 2018.  Participation was open through end of 2018.

There were actually a total of 83 votes, but 6 respondents indicated they do not use 70cm or only listen from time to time. This would have represented 7.22% of the total results. All details below do not include those 6 responses since they do not actively use 70cm spectrum in the United States.

Maybe 2019 will be different for those and others not currently using 70cm for many different activities.  Here are the results of the 2018 survey.

Methodology & Goals

The reason to run a survey was to quantify the current and major use cases of the 420-450 MHz amateur spectrum in the United States. There is currently a huge disruption taking place thanks to digital voice communications through modes such as DMR, Fusion, D-Star and others and a survey helps to add fact to this statement.

The survey included 10 questions focused on use cases or common applications of the spectrum in question. These questions were than able to be aggregated into 5 general categories of:

• Analog FM Voice - Repeater based communication, Point to Point Simplex and short range hot spot use for things like Echolink were the three questions asked. The survey indicated 44.17% of active 70cm users use analog FM communication methods.

• Wide Band Modes - There was only one question asked in the 2018 survey about wide band modes and focused on amateur television or ATV. This type of activity requires channels four or more times wider than the widest audio only modes.  Only 2.41% of the survey respondents use wide band modes in 70cm spectrum based on the 2018 survey.

• Digital Voice Modes - Repeater, simplex and hot spot use cases were the three digital voice mode use questions within 70cm spectrum. For relatively new technology, an impressive 23.38% of survey takers reported to use digital voice as a primary activity on 70cm in the United States.

• Weak Signal Modes - Two weak signal questions were asked that covered single side band voice (SSB) and all other terrestrial or natural objects often associated with weak signal work such as beacons, EME bounce, Morse code and other things such as FT8, PSK31 and WSPR.  11.69% or survey takers enjoy the challenges of weak signal mode operation on 70cm with 7 of 9 category votes captured by SSB, likely during UHF contest periods.

• Satellite Modes - Only one question was asked since most all satellite operation takes place in a protected portion of the 70cm spectrum from 435 to 438 MHz. Uplink and downlink use of any mode used to make contact through man made objects like a space station or satellite were easy to ask in one question in the 2018 survey. With 18.18% of the survey results coming from satellite based use cases, it is clear that amateurs who use 70cm for this reason are active and create a strong reason to have dedicated spectrum for this sort of application. Most any mode is permitted and 2019 will start to see a rise in digital voice satellite use thanks to the recently launched and operational D-Star ONE.

Additional Survey Insights

The below table lists out all questions 9 of 10 questions and the category they contributed towards.

Some Additional Thoughts

Considering at of the end of 2018 there are 755,416 licensed radio amateurs in the US according to official FCC records, this survey sample size is microscopic. However, the total number of active annual radio operators is probably closer to 20% (1 in 5) This would equal 151,083 of  active amateurs in the last year somewhere across all amateur spectrum and not just on 70cm.

The QRZ.com website is pretty popular and seemed to be the best place to field a survey since its fairly agnostic and does not favor those for or against the direction of the ARRL which may have clouded the survey results, but likely would have increased the total number of respondents.

QRZ.com may attract more forward thinking amateur radio operators who are open to learning about new and advanced things to do within this hobby where they can be openly discussed. Many members of the ARRL are on QRZ.com, but only the ARRL can report on things from its membership which is only 170,000 as of 2016 or 22.5% of all amateurs in the US.

While ARRL membership totals are pretty close to the number of estimated active amateur radio operators, the ARRL also includes some non-US members, clubs and supporters so may not accurately represent those most active in the amateur community.  Its total membership may only represent a smaller number of active amateur radio operators than it may care to admit but may be changing due to new leadership in 2019.

If we were to consider that possibly 3 of every 10 active licensed hams (151,083) also frequent QRZ.com, the total pool of likely respondents would have been about 45,325 and potentially 1 of every 7 QRZ.com visitors who may have even found the survey area and logged in to take it would mean roughly a total pool of 6,346.

Ergo, 83 responses from a pool of 6,346 is 1.3% which is right on the border for statistically significant survey results considering that a professional firm touts results over 2% as very successful.  A 2019 survey hopefully will do much better.

If a 2019 survey for 70cm use cases can be organized by the ARRL and other organizations on neutral grounds, it would likely be more accurate based on total responses and prove beneficial towards leadership in emerging aspects of the hobby to create better experiences for all amateur radio operators in the United States looking at digital voice operation, best practices and equipment purchasing decisions.

Questions?  Comments?

If you wish to contact the team responsible for this article, please send a detailed email to 4info@hvdn.org  but remove the "4" or your message will not go through.

Reminder:  Upcoming Kit Build Event. Learn More Here.

SSTV: Images from the ISS

Zipping around planet Earth at 220 miles above on October 27th to 29th 2018 was the International Space Station and its special series of image transmissions using amateur radio slow scan television (SSTV)

What is SSTV?

Slow Scan Television or SSTV for short is a method of sending images over very narrow wireless bandwidth with fairly good color resolution in a short amount of time.

There are many different types of SSTV signals or modes and the one currently in use by the International Space Station is known as Robot36 or PD120

145.800 MHz is the "down-link" frequency for amateur radio operation from the ISS.  Sometimes it is used for voice communication and other times it is used for experiments such as SSTV.   On 145.825 MHz is data "packet" APRS operation for two way "text message" like contact with or through the ISS>

How To Receive SSTV Images?

There are two inexpensive ways to receive and decode an ISS SSTV transmission that can be done with less than $50 of equipment, not including the cost of your computer or smartphone.

Method #1:  USB SDR Dongle & Computer Setup 

Wide band software defined radio (SDR) receivers such as the RTL-SDR v3 can be used for many things, including the reception of signals orbiting above you and around you.  

Other things you can use this 24 MHz to 1.7 GHz  "SDR" receiver for include finding your lost car key remote, monitoring smart home devices, listening to weather, music and so much more.

With free software such as SDR#, its possible to record a "visualization" of the signal for later playback and decoding of SSTV signals. The same signal can also be sent from SDR# to MMSSTV software in real time for decoding of the SSTV transmission.

Method #2:  Inexpensive VHF/UHF Hand Held Radio & Smartphone Setup 

A basic dual band hand held radio can be purchased for about the same price or less as the receive only SDR but will also offer the ability to transmit on a narrow range of amateur frequencies also used by the ISS as well as by over 2,500,000 amateur radio operators globally. 

A very simple way of decoding a SSTV transmission is to simply hold the radio next to your smartphone while running the Robot36 application found on in your favorite mobile app store. By turning the radio volume up, the microphone on your smartphone will hear the SSTV signal and decode it. Sample signals to listen to are found later in this article.

The application will decode the received audio with no physical connection to the radio which makes this very easy to demonstrate for those not very computer savvy.  

Antenna Stuff:   Very important!

While any combination of radio receiver and computing device can be used beyond the examples provided, antennas are just as critical if not more so for receiving the best signal possible.

Having what is called a good "Signal To Noise Ratio" or SNR is needed to help differentiate white noise and static from the actual SSTV signal.  Any interference to the SSTV signal will just look like static like on a television screen, so a good antenna helps increase the SNR and produce a better picture

The good new is that the ISS SSTV signal is often very strong and easy to pick up with basic antennas, but a high power directive antenna is a good idea for optimal reception since it will focus the maximum signal strength from the ISS into your radio.

The reverse polarity SMA-J connector is common on Chinese origin radios such
as those for sale by Baofeng, Wouxon and a few others. 

While good reception results will often be had with the including telescoping dipole antenna with the RTL-SDR V3 or the longer "whip" antenna included with many of the inexpensive hand held analog radios such as the UV-8, a directional antenna is a good idea to consider.

Some options that can be purchased separately made by companies such as Nagoya, Comet and Diamond are easily sourced for VHF only of VHF/UHF operation.

It is best to pay close attention to what type of connector on an antenna like this can be used with your radio as they are not all the same.

The SMA antenna connector version of this same antenna is more common for radios
\made by Alinco, Kenwood, Icom, Yaesu, TYT and Retevis.

An alternate and higher gain antenna called the tape measure yagi beam can be constructed with simple hand tools and materials for less than $20.

There is also a ready made antenna available for purchase from the Arrow Antenna Company as well as the Elk Periodic from vendors such as Ham Radio Outlet.

The beam antenna is a great club project or one for a few like minded hobbyists. Many can be constructed quickly at one time if people work together in cutting and preparing different parts of the antenna for final construction..

What does a SSTV signal sound like and how do I find it? 

In order to know what to listen for, below are three very good signals and the resultant decoded image.

Feel free to try decoding these files with the MMSSTV or Robot36 applications to get familiar with the software since you do not want to miss the fast traveling ISS the next time they are transmitting SSTV images.

The "ISS Detector" app for Android is a great way to find out when the ISS will pass over your location next.
You an also track other satellites and even planets too with this program

To find out when the ISS will be over your location next, please visit AMSAT.org for more information about tracking the ISS, satellites and other interesting space related amateur radio topics.

Play MP3 Recording:  10:28AM 10/28/2018 ISS SSTV

Play MP3 Recording:  10:31 AM 10/28/2018 ISS SSTV

Play MP3 Recording: 12:00 PM 10/28/2018 ISS SSTV

How about SSTV with an SDR?

A nice feature with the SDR# software is you can play back a recording of spectrum at any point in time.

This is also called a base-band IQ file and was discussed in prior articles about receiving voice transmissions from the International Space Station.

• Happy Monday Again!; Ashford School and ISS Make Contact

• SDR: Let's Walk To The Space Station?

This file is a base-band IQ file for the "Atlantis and Mir" SSTV image to help with your own testing.

• Download 1200 PM ET SDR IQ SSTV 10/28/2018  (Caution: 225 MB File)

Select the  IQ file option  in SDR#
and play back the 225 MB recording 

Share your success stories, questions and comments below.  Thanks for reading!

Local to Hudson Valley?  Consider Joining HVDN

NEAR-FEST: What is under the tarp?

Since 2006, amateur radio operators, electronics hobbyists and camping enthusiasts have been making the pilgrimage to New England to experience an interesting two day long event known as "NEAR-FEST"

What is under the tarp you ask?  Some interesting electronics with a military
history for sale at the 24th NEAR-FEST in Deerfield, NH on October 12-13th 2018

Held twice annually, every spring and fall at the the Deerfield Fairgrounds has been the home of a unique event called NEAR-FEST.

Part electronic swap meet, educational session, casual gathering, food destination and opportunity to purchase brand new and interesting radio related equipment offers a little of something for everyone in the family.

Over the years, the New England Amateur Radio Festival has attracted those from both far and wide.

The October 2018 edition was no exception with those spotted from Quebec, Ontario, Virginia, Florida, Ohio, Japan, Haiti, Puerto Rico and of course the entirety of the North Eastern United States!

Event attendees can camp on site in a tent, roll up in an RV or camper or stay at any number of area hotels. 

This makes it a very convenient "ham fest" as compared to other amateur radio or even "maker" oriented events.

New England Tech Trek gives another reason to not leave NEAR-FEST too early
if you are not interested in purchasing something which is one of the
top reasons to go to a "fester" like this bi-annual event 

There is no need for every attendee to contend with an early morning drive or risk there getting late out of fear vendors will pack up early.  Once someone is at NEAR-FEST, they are generally there for a while.

Everything from food, ATM machines and restrooms are available to prevent people from leaving 

Helpful NEAR-FEST Tips

It is recommended however, to bring a backpack to hang on to anything acquired at the "fester".  A bottle of water, comfortable shoes, various batteries, rain repellent are recommended to have on hand too.

Need a rain jacket before going to NEAR-FEST?  L.L Bean h
as you covered at its various nearby outlet locations.

Most of these "forgotten" supplies however can be purchased at an L.L Bean Outlet in nearby Concord or Nashua.  This may be especially of interest to those with interests such as QRP kayak portable, SOTA or other converged ham radio/other stuff sort of activities. 

Over the past years, more commercial vendors both at NEAR-FEST and other similar events take credit card payment, so save your cash to support the tail gate community.

Also, if going with friends, agree on what "secret channel" to use and program a few options in advance to your hand held radio of choice.  All of the common "simplex" channels may be in use, but its still good to have those programmed too.

Frequency Suggestions for NEAR-FEST

If you have a DMR radio, the NEDECN has pre-populated code plugs for all area repeaters of interest to NEAR-FEST attendees.

All you need to add are your simplex and "secret" channels along with configuring them in the correct zone, scan list or receive group. Some "amateur radio" suggestions include:

• Standard FM analog frequencies such as 146.520, 146.535, 146.550, 146.580, 446.000 and 446.500 with no PL tone.

• Digital voice DMR frequencies such as 145.510, 145.790, 446.075 and 445.925 saved with TG 99, TS1, CC1. 

• Your own "secret channel" using FM analog, DMR or some other mode like Fusion or D-Star on 433.0125, 433.920, 147.030 or 223.500

Various DMR radios by Anytone, TYT, Vertex, Motorola and a few others can
easily be programmed for NEAR-FEST thanks to NEDECN's informative website

You can also try one of the "unlicensed" channels for FRS and MURS in order to include your not yet licensed amateur radio friends. A great radio for events like this are the Xiaomi Mijia with smart location sharing reviewed in the past on HVDN.

This inexpensive radio not only is a great discussion topic, but also serves dual purpose for both amateur radio and unlicensed operation in one friendly looking design. No internet is needed for this to work, compared to trying to share location with Google Maps or verbally explaining your location over the radio.

Time To Learn & Get Edu-ma-cated... 

An exciting addition to NEAR-FEST recently is the second annual New England Tech Trek or NE(T)².

This mostly hands on educational event engages children as young as 8 years old all the way up to and beyond the age of 80 years old.

For those not familiar with amateur radio and its infinite list of complexities, NE(T)² helps capture some of what amateur radio is all about to prospective "hams", existing hams or those newly licensed thanks to exam sessions also available at NEAR-FEST.

This year, New England Tech Trek showcased a range of well known habits of the amateur radio hobby that have seen modern changes as well as purely new and innovative applications and technologies relevant to any communications focused hobbyist.

NEAR-FEST XXIV Report

Friday October 12th and Saturday October 13th were the planned days for attendees to enjoy the event and rain only impacted part of Saturdays festivities before the event officially came to a close at 3:00 PM Eastern Time.

Inside three buildings were vendors of brand new equipment and small components. Outside and scattered between various food stalls were tail gate and "tent gate" vendors selling everything from surplus "militaria",  antennas, computers, rechargeable batteries, VHF/UHF radios, HF amplifiers, microphones and test equipment.

Some of the commercial vendors or service providers at NEAR-FEST XXIV included:

• KJI Electronics
• Quick Silver Radio
• Radio Oasis
• Dave's Small Parts of Shokan, NY
• Tune Up Clinic by Andy WA2CDL 
• Ham Radio Outlet
• GEMOTO
• Connect Systems Inc
• Plus about 30 more....

Not Just "For Sale" Stuff

There also were organizations focused on various parts of amateur radio visibility scattered throughout these rain proof building to help raise awareness of different parts of the amateur radio community that are built upon like minded members.

The Nashua Area Radio Society was just one of the
organizations that made the NE(T)2 event possible at NEAR-FEST XXVI

Was the ARRL there?

Aside from the expected ARRL attendance via a small table, other leadership and influencers were at NEAR-FEST also making a much larger presence known.

One of the non-commercial sellers had a monitor
that said "My wife said to take all reasonable offers" 

Key organizations present included one of the longest operating female oriented amateur radio clubs called YLRL which showcased its bi-monthly newsletter called YL Harmonics.

Niece, KA1ULN  was enthusiastic to engage with those who braved the weather to attend NEAR-FEST XXVI and it was great to meet her in person.

A national women's only amateur radio organization promoting the hobby since 1934

Booths for various geographic focused clubs such as White Mountain Amateur Radio Club, Nashua Area Radio Society, and the New England Digital Emergency Communications Network to name just a few helped make this a great way to decide who else to spend precious "membership" dollars with too.

Many of these organizations use NEAR-FEST as a great way for its membership to see each other in person as well as to raise funds for club activities through the sale of surplus member equipment, spare parts and even member driven projects.

Craig, N1SFT, oversaw some VYL (Very Young Ladies) complete
a small kit that required soldering 

Pictures, please!

The mixed smell of pine needles and grilled pepper & sausage sandwiches permeated the damp fall air across the fair ground which added to the overall great atmosphere by a well run and planned event by those responsible.

Thank you for all your hard work and effort for yet another NEAR-FEST!

Here are some further photos and commentary related to the event.

Most Curious Antenna Award

At the fall NEAR-FEST of 2016, Steve K2GOG (Co-Founder of HVDN) was seen walking around with a high gain 2.4 GHz antenna which attracted a lot of attention.  For the asking price of $5, it was hard to pass that up. This can be found on his QRZ.com profile page

This year, he was on the look out for something else very interesting to add to the antenna collection, but decided to pass on this 900 MHz corner reflector antenna based on its size and price. This could have been easily modified for 440 MHz, 1.2 GHz or maybe even a lawn chair!

Best Convergence Hobby Tailgate Vendor Award

There is much to say about this photo ranging from the precision GPS antenna attached to the roof of the Toyota RAV4 with the license plate of  "Hiker" to the bumper sticker that could relate to the load of vintage test equipment or his other favorite activity that is not ham radio

Hiker Trash:  Certainly, you wont win any feather-lite
pack tips if trying to take any of this gear out on the trail

Most Popular NE(T)² Discussion Topic Award

Anything to do with satellite operation was a big topic of interest inside the NE(T)² as well as outside. The impressive antenna array used for satellite communication demo  that made use of crossed polarization  14 element 435 MHz Yagi, 7 element 145 MHz Yagi and a 20 element 1200 MHz Yagi on a azimuth/elevation rotator. This is one impressive (and expensive) antenna system!

This impressive satellite communications array is capable of receiving
very weak signals as well as for transmitting very high power for
long range line of site communication

On a much more simple and cheaper scale was the Elk Log Periodic antenna found inside the NE(T)² building. T\

This much less expensive but effective antenna can be used to make contact through low earth orbit satellites such as those covered in the popular "Amateur Satellite Basics: Where, When & What to listen for" article from March 2018.

Not to be left out with all the satellite communication focus is a
high altitude balloon presentation at the right of the small crowd.

Digital Mobile Radio Robustness Network Award

The New England Digital Emergency Communications Network connects over 80 different repeater sites over much of the north eastern United States in order to create a very robust communications network.  The KM3T and W1RCF repeaters located on the fun to (mis)pronounce Mount Uncanoonuc  are part of DMR-MARC which is a different network than the popular Brandmeister network.

Both DMR networks are mostly able to talk to one another though due to great interoperability between those responsible for these tremendous contributions to modern amateur radio communities globally.   NEDECN had many radios on display such as the popular Anytone AT-D868UV along with some Motorola equipment for sale by one of NEDECN's members.

NEDECN did a fantastic job or promoting DMR at NEAR-FEST and they even operated a repeater for NEAR-FEST communications.

Reach For The Sky Award

Any time a number of amateur radio enthusiasts gather is the time to see who has the largest antenna on a car.  Here is one example of an HF mobile operator with a 8 foot long vertical antenna on a station wagon. License plates have been blanked out to protect the identity of this super ham-heros!

The Not Just Ham Radio Presentation Award (Tie!)

Computer and Maker enthusiasts were represented by a presentation about what can be done with a Raspberry Pi.

And, for those looking to get out and do something fun with a Raspberry Pi or antenna project can experience hidden transmitter locating or "Fox Hunting".

A very effective directional antenna can be constructed out of PVC pipes, hose clamps and a measuring tape.

The Last Picture Award 

With the weather getting a little more wet on Saturday, even the "hard core" military ham radio crowd started to pack up early.

Mystery Picture Award

Care to take a guess as to what this is? Sound off in the comments...

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