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.

RTL-SDR V4 compared to RTL-SDR V3

HVDN prime author Steve K2GOG received two of the RTL-SDR V4 during its initial production run. 

Here we are about four months later and there have been many other reviews focused on basic differences between the two devices. 

There have also been impressively fast integration of the new drivers along with popular software. By mid September, almost everything was solved but I waited a while to do this article now that production has resumed and the V4 is easily found again until the R828T chips run out.

Almost every video or article focuses on the same things like which one works better for HF reception or other pretty basic things. There are some major differences where the V4 really shines and that is what this review is about.  Our goal is to NOT focus on the same thing and to not try to force our readers to buy one over the other, unless the below is of interest to you.

Please note, get the right antennae for what you want to do. Using telescoping crap antenna is not going to work well for almost everything we cover below based partially on the spectrum coverage chart below.

Directly from the "RTL-SDR Blog V4 Dongle Initial Release" article, there are some major things to point out.

• 0-30 MHz Spectrum:  This has been beaten to death already. The V4 is much better at HF reception compared to the V3, but you still need to have a real antenna. Do not take shortcuts here as a marginal 2-3 foot (1m) telescoping whip is not going to impress you.  A major benefit is not having to select Q branch to receive the "short wave" spectrum, so with the right software the overall user experience is still better here.   It is worth noting that comparing the V4 to even the inexpensive "knock off" SDRPlay devices for around the same price still offers better HF spectrum coverage along with wider 10 MHz bandwidth compared to the V4's 3.2 MHz bandwidth.  Its time to move on. The RTL-SDR is fine for what it is and stop focusing just on this spectrum as a selling point.

• 100-300 MHz Spectrum:  There are spots where coverage is slightly better with the V4 compared to the V3. Its not worth getting into much detail here, but the built in triplexer and filtering does a better job limiting out of band broadcast interference from the 88-108 MHz range, especially if you are interested in civilian aviation VHF 118-136 coverage as well as other amateur or utility communications.

• 315 & 433 MHz ISM Spectrum:  If you really want to explore what is around you or wish to think you are some sort of "hacker" having better sensitivity and filtering around the 315 MHz range used for tire pressure monitors found on many vehicles in North America and the shared 433 MHz ISM range with many "Internet of Things" devices and amateur radio things is a huge gain here.  This was worth the expense for these monitoring target applications.

• 868 & 915 MHz Sub GHz Spectrum:  Another area of improvement with the V4 device.  Many IoT devices worth sniffing around exist here. While the V4 does seem as if it is not as sensitive compared to the V3, I feel this is not too bad since it forces the user to use more purpose drive antennae to make up for the difference. 

• >1000 MHz+ Spectrum:   North of 1 GHz, performance is not really that bad with the V4 and with an LNA, better antennae or combination of the two is fine.  Over time, the two V4 devices have been tested to have slightly less thermal drift and lower power consumption compared to the V3.  In many cases where monitoring L Band spectrum, this becomes important since the RTL-SDR's have been installed in areas not very accessible or have had to contend with heat build up.   For applications like HRPT satellites,  ADS-B, and so many other things found in the 1000-2000 MHz slice, the V4 has really been great when uses with purpose focused antennae.

Lazy Summary

We are talking about an under $40 USD device. Stop being cheap. Stop pretending this will be the best radio receiver ever made. Stop using crap antennae and blaming the SDR or the software. Stop thinking the world revolves only around HF spectrum.  Buy an RTL-SDR V4 if you are interested in doing many things which will motivate you to explore better antennae and software where you can find really cool things in the airwaves that may just be data signals and not just human voice communications.

Other Things

I really like the indicator light for when the bias T power is active. The L band patch made by RTL-SDR has an indicator, but its inside the antennae housing so is not viewable. Knowing the small green light on the V4 is on, does help ensure I know the antenna downstream is seeing power has been helpful Many software packages like SDRangel allows control of the bias T power, but a physical indicator is still nice.

Overall design in such a small package is hard to do.  We may be at the limits of what else can be done in this formfactor but with thermal management becoming more challenging, its commendable how the power supply has been redesigned. Earlier SDR suffered greatly from power issues, this is not the case with the V4.

If there were two front end major changes, I would love to have a built in dedicated high isolation filter which pretty much knocks out the entire 88-108 MHz range up to 60db since strong signals tend to mix at odd places at times or have a tight filter around 400 MHz for better ISM or radiosonde monitoring between 400-450 MHz.   Otherwise I am just picking on things I can solve other ways via outboard filtering or mission specific antennae with usually do a great job at out of band attenuation.

Use it or lose it: Death of 3.4GHz

Wireless spectrum is what makes amateur radio valuable. Without the ability to experiment at different frequencies, "ham" radio will stagnate into being known only for what was up until today 0.0163% of its total available spectrum. This is totally NOT fair! 

What else beyond HF?

The high frequency HF or "shortwave" bands which are used for long range communications is what much of the public know amateur radio for. In times of emergencies or most any regular day or night, very low speed data or narrow band voice communications can be heard across a variety of sub-bands that are only to be used for amateur radio mostly between 1.8 MHz and 30 MHz.  Moving higher up the spectrum chart, much higher speed data and digital voice communication has been gaining in popularity globally.

As noted in a past presentation on satellite communications given at the Trenton Computer Festival when humans were able to gather in social settings with no fear of global pandemic,  Steve K2GOG shared an overview of how much discontinuous spectrum is available to all three classes of amateur radio operators in the United States.

Amateur radio satellite communications

While ham radio is known for its long history surrounding the so called "short waves", once you get beyond 30 MHz, the actual wavelengths get much, much, much shorter and commercial users have long used spectrum just above or below where amateur radio operations live in the VHF, UHF and SHF spectrum. Within these higher bands, there are specific portions set aside for satellite communications.

While there are some tiny portions of amateur radio spectrum that are dedicated for only satellite communications, they add up to over 300 MHz in what could be considered the more easily accessed spectrum between 7 MHz and 47 GHz.

While there is no commercial users likely looking to take back spectrum under 30 MHz, there are a few HF satellite frequencies in use, with examples being the very old AO-7 satellite and a few new Chinese satellites that will start using the 21 MHz band. 

Most amateur radio operators have been exposed to educational school contacts or narrow band picture sharing known as "slow scan television" by way of the International Space Station which mostly uses the 145 MHz spectrum.   

More specific satellites that act as "bent pipes" or repeaters often use 435 MHz as an uplink frequency and 145 MHz for a downlink.  To date, there is limited use of other frequencies above the 435-438 MHz satellite band, with satellites such as AO-91, AO-92, SO-50, FO-29 and RS-44 as a few of the more popular satellite destinations for amateur radio experimenters today that use these frequencies.

The AO-92 satellite also uses a 1.2 GHz uplink during specific times to help show use by the amateur radio community in an otherwise less frequented portion of spectrum, which much like the 3.4 GHz band, has been under attack from commercial users who could benefit from valuable amateur radio spectrum.  

The QO-100 satellite relies upon a 10 GHz downlink and 2.4 GHz uplink and this makes it the most advanced satellite that is accessible to amateur radio operators today, but just not in the United States due to its stationary position covering all of Europe, Asia, Africa and parts of South America.

The neighbors have better stuff

Over the past two years, European regulators such as CEPT and OFCOM tried to to make a case to take away parts of the 145 MHz, 1.2 GHz, 2.3 GHz and 3.4 GHz allocations to help expand different commercial services such as long range aircraft positioning and different "Internet of Things" applications along with different applications that can be considered as part of the 5th generation of mobile communication, often shortened to 5G. 

While fending off the recent attacks on the important bottom part of the L-Band from 1240-1300 MHz was successful as well the somewhat distracting 145 MHz allocation battle,  the spectrum just below the common 2.4 GHz Wi-Fi band was lost to commercial users in Europe. 

Within the United States, the Federal Communications Commission has decided to "delete" the ability for amateur radio operators to use its allocation in the 3.4 GHz band due to the needs of 5G, especially that of CBRS which will drastically change the way spectrum is licensed moving forward.

We need to change

There is nothing wrong if HF focused operation is what is of most interest to you or anyone looking to get involved in amateur radio today. Those that decide to just spend a casual weekend enjoying the already well understood and no longer innovative 3.7 MHz, 7 MHz and 14 MHz bands are akin to being a bunch of "home bodies" and those that are easily pleased and that is ok.

While it is possible to take HF equipment out in the field and operate from battery power and make contacts with others using voice, Morse code or digital data modes such as  PSK31, FT4 or JS8CALL, this does not advance the hobby if we are trying to defend our spectrum. This use case demonstrates a level of converged activity.

In the next few decades, the novelty of HF based communication will be much harder to entice a next generation of amateur radio operators to unless they first are shown all the amazing things that can be done across other frequencies and applications such as satellite based communications.

We owe it to the next generation of prospective amateur radio enthusiasts to find differentiated applications for the 144 MHz, 435 MHz, 1200 MHz and all the way up to 60 GHz if we wish to remain relevant  rather than as a forgotten hobby deep rooted in the evolution of electronic innovations we have seen over the last 100 years.

Presentation: Sensing The World Around You

HV Open is the premier open source software group of the Hudson Valley, formerly known as the Mid-Hudson Valley Linux Users Group (MHVLUG) that Sean Dague and others founded in 2003.

MHVLUG made the shift to fully embrace open source beyond just Linux a few years ago and created the reason to change names. Current leadership anchored by Matthias Johnson, Joe Apuzzo  and Jack Chastain have done a fantastic job along with Sean by seeking additional presenters of related topics to illustrate how much more widespread open source software has become with languages like Python being one of the most popular for those looking at SDR or IoT applications.

SDR & IoT: Sensing the world around you with open source software

HV Open was interested for HVDN to give a presentation on software defined radio at its monthly meeting held on the grounds at Vassar College in Poughkeepsie, New York. The slides can be found in our presentation repository. The presentation was given by Steve Bossert.

Why open source matters when talking about SDR and IoT?

Amateur radio as a hobby is under immense change due to technology advancements, relevance, use cases and public perception.

The goal of this presentation was to highlight beyond amateur radio where there is innovation and opportunity to converge with other hobby groups and exchange knowledge, inspiration and expertise.

Presentation Highlights

HVDN members create high impact and engaging presentations and this one was no exception.  For the 20 or so HV Open supporters present, they were treated to a video based on the often imitated Star Wars opening movie sequence to help set the stage for a great overview followed by a Q&A session.

Beyond what was captured in the presentation, there was a good bit of hardware demonstrated alongside Steve's presentation to help illustrate that an entry into SDR can be done at low cost by way of the popular RTL-SDR V3 USB receiver and the even more "covert" NooElec Nano 3 USB receiver.

For those interested in obtaining an amateur radio license and the ability to transmit with an SDR the Lime SDR Mini or the ADALM Pluto are two popular options.

All four SDR will work with the software Steve covered in his presentation and certain applications can be run not only on a regular computer or laptop, but also a Raspberry Pi or even a small Wi-Fi travel router such as those sold by GL.iNet that run OpenWRT.

From rear left to right - Zopsc wireless vibration sensor, GL iNet MT-300, AcuRite 02097M
From front left to right - Lime SDR Mini in custom 3D printed case, NooElec Nano, RTL-SDR V3

With any SDR device, different transmission sources such as common temperature sensors like those sold by AcuRite which mostly transmit in the ISM spectrum around 433 MHz. A different type of sensor presented was by a more obscure vendor named Zopsc and can be used for a variety of security applications.

Using a common USB power bank and external antenna such as a small 433 MHz magnet mount are all that is needed aside from an SDR and travel router to create a very flexible and light weight portable monitoring station for IoT devices.

For those interested in a more complete and "professional looking" implementation of a remotely accessible SDR, Steve showed off his slightly over engineered and re-purposed example of such a device. Inside the blue commercial battery enclosure he sourced from the "maker's crown jewel for parts" of the Hudson Valley called P&T Surplus. Here is a basic block diagram inside this rugged enclosure.

The 12 V to 24 V DC converter is not needed for this all to work nor is the external Ethernet port or PoE splitter but were added for flexibility to use the remote SDR setup to provide power and connectivity for longer range Wi-Fi with a Ubiquiti Bullet M2 for mesh networking applications.

Power from the high capacity battery can run the basic implementation of the travel router and SDR for over seven days continually or for a few days less when using the "power over ethernet" mesh device.

All the cabling is interchangeable for easy application changes ranging from standard spade clips for DC power connections to the Ethernet and SMA antenna ports.

Using a remote SDR for IoT sensing

It is very easy to install rtl_tcp or rtl_433 onto the OpenWRT enabled router to share what is received by the SDR with any computing device that has Wi-Fi access.  

A benefit of a remote SDR is no loss of signal or more convenient placement of your IoT sensing antenna and then be able to capture, analyze and use the signals from the comfort of your kitchen table or office with no wires hanging around to trip over.

Open Source Software & SDR

The many options explored in the presentation for software are tough to capture in detail via this article summarizing the presentation, but should act as inspiration to explore Git in more depth as well as other open source software repositories as well as future articles on HVDN or presentations.

There is much to experiment with from both the hardware and software perspectives involving software defined radio and the internet of things and this presentation merely scratched the surface.

Terms like machine learning and artificial intelligence are already catching on within the SDR community as well as in IoT or open source as touched on in Steve's presentation. 

Interested in customized presentations for your group?

Since the inception of HVDN in 2017, we have supported the the Mid Hudson Valley Astronomical Society, the Squidwrench maker community,  Trenton Computer Festival and HV Open with engaging presentations to spread the word about the convergence of amateur radio with other hobby groups.

If you are interested in inviting in HVDN to give a presentation in the general Hudson Valley region of New York or slightly outside our beautiful borders, HVDN leadership can be contacted through the HVDN Notebook blog as well as via our contact page on the HVDN.org website.

SDR & IoT: Sensing the world around you with open source software presentation

--Download here--

FiPy > Raspberry Pi: Wireless Rumble

Imagine 5 networks in one perfectly-formed, same-small-foot-print development board that is MicroPython enabled. The Pycom FiPy board includes WiFi, Bluetooth, LoRa, Sigfox and dual LTE-M (CAT M1 and NBIoT)  In one product, the FiPy gives access to all the world’s LPWAN networks on one tiny board.

Processing Details

• Espressif ESP32 SoC

• Dual processor and WiFi radio system on chip

• Networking processor handles the WiFi connectivity and the IPv6 stack

• Main processor is entirely free to run the user application

• An extra ULP-coprocessor that can monitor GPIOs, the ADC channels and control most of the internal peripherals during deep-sleep mode while only consuming 25uA

• 2 x UART, 2 x SPI, I2C, micro SD card

• ANalog channels: 8_12 bit ADCs, 2_8 bit DAC

• Timers: 2_64 bit with PWM with up to 16 channels

• DMA on all peripherals and up to 22 GPIO

Physical Interface Details

Additional Details

There is far too many great specifications to list, so have a look a look below for details.

Ground Hog Day: Why does HVDN care?

If we think about the last 100 years of wireless technology and development, amateur radio has often been closely aligned with the latest innovations and finding ways to leverage them across our globally aligned licensed spectrum. 

Today,  far too many within the amateur radio ranks are complacent in only spending time with applications long since established and keep doing the same thing, over, and over, and over.

While there is still much innovation taking place within amateur radio that the general public is not aware of, our goal within Hudson Valley Digital Network (HVDN) is to focus on what is next and find ways to bridge that back into our hobby interests.

If we can share that with other communities such as those interested in programming, making and every possible convergence of hobbies ranging from agriculture to astronomy, that would be amazing

So now what?

Many of us involved in the formation of HVDN also work for a variety of well known technology organizations and somehow still find some time to unwind in our off hours in experimenting with new things. 

The upcoming Pycom New York event on September 9th 2019 seemed a perfect way to dive in even further, so expect good detailed review of this fascinating workshop. 

Spoiler alert

Timing wise, this was also perfect as we have been busy experimenting with ways to leverage LoRa technology within amateur radio and how to integrate it in to many well known amateur radio related practices.  

Be sure to watch this space closely as we transition much of our focus towards Micropython, IoT, LoRa and a few other related themes to keep up with the digital and innovation themes we have worked hard to build.  

Upcoming Event Notice

On October 24th 2019 at a soon to be determined location will be the first HVDN official involvement in "Open Source Hardware" month along with our good friends from "Squidwrench" where we collaborated on the oscilloscope build project earlier this year and HV Open, which offers great monthly presentations mostly around open source software.  

P.S:  Would be nice if we could somehow get Bill Murray to attend since he still appears to live nearby within the Hudson Valley, even though his house is for sale. Kegger at Bill's? :) 

Are you posh or not? Tracking aircraft

Fit together a raspberry pi computer board, a trick of a USB SDR dongle plus some bits and bobs of software and antenna to roll your own personal aircraft tracking device for under 50 quid.

A Daft British Mystery

Above you every day are any number of craft zipping about too and fro with all of them emanating various wireless signals.  Some are the aircraft crew reporting via voice radio for arrival instructions, post departure issues, air to air communication checkups and more.  Data radios receive detail on surrounding aircraft to prevent collisions while others transmit operational parameters up to orbiting satellites, ground stations or curious blokes like whomever may be reading this.  From the largest to smallest aircraft, there are many different types of wireless systems focused on specific tasks.

Just this morning in east of the beautiful Hudson Valley area of New York was a private aircraft of sorts with the call sign of "2 Posh" flying through at 39,200 feet at between 521.3 and 522.5 miles per hour . The registration details came back as a Cessna Citation CJ3 with the international civil aviation organization identifier of 43EC0E.

This was not the first time this aircraft has passed through the area according to the data generated by the signals received by the ADS-B receiver and logged automatically via mySQL database. It was only realized while running a query of military aircraft that have passed through in the last day. For some reason "2 Posh" was tagged as a non-commercial or private aircraft which is interesting. Plus, it also had the aircraft type of C25B which is a version of the Cessna Citation that makes it quite the speedy high flying jet according to the detailed Wikipedia page on the subject.

Data analytics & wireless signals as a hobby

Perhaps the largest self identified group of hobbyists involving wireless signals is held by amateur radio, since they all need to be licensed by government agencies around the world if they will be transmitting within the allocated spectrum reserved for such people.

Another hobby called "Plane Spotting" involves no such licenses and maybe only some common sense.  Participants often take photos of aircraft and create scrap books of interesting craft. Some take this to another level by monitoring aircraft communications. Information gathered is not necessarily secret since anyone can see airplanes flying around, but what about tracking them?  This opens up a somewhat secret aspect of plane spotting that if used incorrectly, can create security issues.

For people with interests in areas like analytics, wireless technology, relational databases, embedded computers, internet of things and probably another 1,000 things - setting up your own inexpensive ADS-B receiver for real time, unfiltered air traffic data could be of interest for personal use or to create a shared network of receivers feeding into one database or user interface to cover a wider area.

Many commercial websites such as Flightradar24, Flightaware and others do not offer the same details but you can replicate something very interesting at minimal expense and learn about a ton of unknown things like how certain wireless signals propagate and how to create optimal antennas for different applications.

Further Learning: Insert Ideas Here

Amateur radio spectrum includes access to the 1240 to 1300 MHz range for all license classes in the United States.   ADS-B signals used to track aircraft are found at 1090 MHz and travel much in the same way.   VHF 118 to 136 MHz voice channels for aircraft which can be received with the same inexpensive receiver as ADS-B are not too different than the amateur 144 to 148 MHz frequencies.  

From a satellite perspective, there are options for aircraft tracking via L-band satellite services in the 1500 to 1700 MHz spectrum with the exact same inexpensive receiver. 

What else can you do with aircraft data or the same hardware?  Many things. More details on setting up your own ADS-B receiver can be found here.   HVDN also offers its members with access to our very own network of receivers for a small donation or no charge depending on your level of membership.

Almost forgot....  the aircraft known as 2 Posh may have something to do with a former member of the Beatles or extended family.

Details:   https://hvdn.org/adsbmoreinfo