Wednesday, May 15, 2019

North Star Digital Net: Presentation on BlueDV

The weekly North Star Digital Net held every Tuesday evening at 9:00 PM Eastern on DMR talk group 31630 (STEM).  Any amateur radio operator is welcome to attend. 

Access via All-Star and Echolink is possible to through Hudson Valley Digital Network with details on that at for those without a DMR radio or not able to use a radio at the time of the discussion.

Net control, Jim WA2UMP often turns over the floor to someone knowledgeable on a specific topic followed by a Q&A  session.

This week featured Rick, W1RHS who shared information about the popular BlueDV application. BlueDV allows you to create a hotspot for digital ham radio modes under Windows, Linux, Android and iOS. 

BlueDV allows you to create a digital communications platform under these operating systems using only a computer, tablet or phone and using the computer or devices speaker and mic.  

The presentation covers the DVMega radio/modem board combined with the BlueStack board for USB or Bluetooth connectivity and the AMBE 3000 dongles with AMBE Server.  

There is a comparison between BlueDV and PiStar and a review of the DVMega Cast network radio. Not covered in the presentation is "Peanut" which is one of many growing applications used to augment access into digital voice infrastructure today.

Download a copy below and be sure to check back next week if you have further questions.

More details:

Tuesday, May 14, 2019

Line Of Sight: Aircraft Edition

Definition: Line of Sight

Aircraft and radio waves are two great examples to talk about regarding line of sight.

Simply put, the higher the aircraft flies, the further a ground station can receive transponder signals at 1090 MHz or 978 MHz originating from an aircraft.  Obstructions on the ground such as mountains and tall buildings can obstruct the ability to receive all ADS-B transmissions at the ground level too.

The technology covered in this article is known as automatic dependent surveillance broadcast or ADS-B for short. A fancy GIF animation at the end of this article will help visualize reality from theory even further!

Compare:  Fact and Fiction   

The website "Hey, What's That!" is useful for identifying mountain peaks and line of sight for different forms of communication. The below map shows the theoretical range of ADS-B communications up to 10,000 and 30,000 feet elevation from the chosen center point at a known height.

Poughkeepsie aircraft hobby remote control plane drone

Ground based obstructions have been accounted for on the map as noted by some local summits with the red push pins that make for great amateur radio SOTA destinations. 

A calculation of 47 foot above ground level for a total height of 256 feet was used for the same latitude and longitude coordinates six digits past the decimal point on the "Hey, What's That!" website in order to match the location of the HVDN ADS-B antenna location with high accuracy.

boeing aircraft KPOU IBM helicopter
The "Blue" center dot clearly is not in the center. of the reception range. Its location was moved to calculate the distance to all aircraft from where I was located while I was authoring this article. This is one of many features available to those that gain access to the HVDN VRS. Details about HVDN membership can be found at the end of the article.

Comparison of the theoretical and real world values are very, very close when looking at both data sources.

Had the ADS-B antenna been located outside and above the roof line just a few feet higher, its possible that the two results would have been even closer.

The dark red "splat" is the historical reception report over time for aircraft up to 30,000 feet. The pink splat is for aircraft under 10,000 feet.

However, there is one thing to take in mind here, aircraft are not flying in every possible location which will account for some gaps in coverage when looking back at the theoretical map.

Is it worth the extra work in adding an outside antenna to gain the additional coverage benefits? This certainly is shaping up as a classic case of diminishing return, so read on to show how this was validated.

Detail:  Spot checking some results

The top photos are captured from the "Hey, what's that!" website for theoretical "potential" results. The lower photo is zoomed in from the HVDN Virtual Radar Server to complete the comparison against fact to cover real life reception results.

10,000 Foot Elevation Connecticut Comparison:   The projected range spike towards and over Springfield was accurate from the projection and actual reception results.

Add caption

30,000 Foot Elevation Finger Lakes Comparison: Coverage was just short of the prediction over Cayuga Lake, but awfully close.


10,000 Foot Elevation Long Island East End Comparison: Coverage fell short of the North Fork at 10,000 feet but air traffic is captured as noted by pictured aircraft which were at 14,000 and 18,000 feet pictured to right of coverage overlay.

hamptons 2m repeater hVDN

30,000 Foot Altitude Over Delaware Bay Comparison: Coverage was pretty accurate based on traffic spikes compared to theoretical results.

Further Results:  Comparing Other ADS-B Feeder Sites

According to Flightaware's website, there are a number of close proximity feeder sites to where the HVDN primary site is located in the Hudson Valley of New York.

Only the two highlighted receivers on the map (Orange) have similar coverage of HVDN which must mean that the height above sea level for all three stations must be similar and may even be using near identical reception equipment to that of HVDN (Red)

Here is further evaluation of the public details each of the three stations provide.

Receiver Site #1:  Montgomery, NY - Flightaware 87114

Receiver #2: Poughkeepsie, NY - Flightaware 77960

Receiver #3: Middletown, NY - Flightaware 83104

For Fun:  What if.....

It would seem for the Hudson Valley, few interested seriously in ADS-B reception can really improve reception without a huge height increase or locating the antenna outside.

Steve K2GOG of HVDN thought it would be fun to model the benefits of increased antenna height, so check out our amazing use of animation skills below to see how much higher you need to go to literally receive every aircraft possible via line of site up to 10,000 (Orange line) and 30,000 (Blue line) feet.  

hvdn aircraft, ads-b range distance

Perhaps it may be worth while putting the antenna up another 30 feet located outside. Interested in setting up your own ADS-B aircraft receiver?  Helpful links follow:
Another approach may just be easier to recruit ADS-B feed providers to just aggregate into the HVDN Virtual Radar Server to increase the range of reception for aircraft under 10,000 feet. Contact the author if there is interest in contributing to this.

Thursday, May 09, 2019

May 2019 Global Digital Repeater Round Up

It is that time of year again, where Hudson Valley Digital Network analyzes the growth of digital voice amateur radio repeaters and provides some additional commentary behind what is helping to push towards the future of mode modulation.

Why May and October?

The month of May in most parts of the world means nicer weather and the start of the hamfest season in many countries. In the United States, many vendors typically announce new products just before, during or after the three day long Hamvention formerly of Dayton Ohio but now held nearby in much more "modern" facilities in nearby Xenia.

This event often impacts purchasing decisions of both end user devices (hand held radios, mobiles, hotspots) and wide area infrastructure such as repeaters or so called "mega-spots".  Taking a measurement just before this event helps not only provide normalized results, but give readers an opportunity to see a big spike in growth just after should they wish to look into this themselves!

The Anytone D878UV is a very popular DMR radio
due to its feature set, price, durability and accessories.
October is the next update before the onset of winter and holiday shopping season when vendors sometimes run promotional sales. Measurement at the start of the fourth fiscal quarter helps provide more normalized measurements to track how things are looking for the future of digital voice mode growth.

May 2019 Digital Repeater Growth

Basing HVDN's measurements on public data has multiple benefits.  This website is widely used by the amateur radio community and captures almost all repeaters globally. Most all heavily used repeaters will be listed here and the operators of these resources usually like to let others know they exist to highlight the technical expertise it takes to run a good repeater. These are the two major benefits and why we chose to base our analysis only on this websites data.

The data above tells a great story. DMR continues its upward trajectory mainly fueled by inexpensive hand held radios and hot spot devices which create the need for wide area repeaters.

Growth of DMR repeaters over the last 12 months was 18.6% which equals 34.4% of all total digital voice repeaters for the top 5 digital voice modes.

The single vendor supported FDMA based Yaesu Fusion mode grew a respectable 12.6% from May of 2018 to present.  With lowered cost hand held and mobile radios along with a few promotions that resulted in sold out or back ordered equipment early in 2019.

Some other reasons the mode also known as YSF or C4FM has been widely popular are its fuller range audio and easy programming requirements compared to most all other digital voice modes.

Icom's D-Star continues to struggle thanks to its limited and higher cost equipment. There was not a single new D-Star capable radio offered for sale in the last year that fit into the hand held of mobile category.

Aside from the Kenwood TH-D74 which is the only non-Icom radio to support D-Star the only new radio capable of D-Star is the $2,099 USD Icom IC-9700.

This high end base radio will appeal more towards those interested in satellite or weak signal communications in the 2m, 70, and 23cm bands. While the radio is capable of D-Star operation, this radio will likely not cause any uptick in repeater growth.  Of the three major digital voice modes, the 15 year old GFSK based D-Star only saw 2.9% growth.

Commercial To Amateur Impact

DMR started life as TDMA based MotoTRBO offered to commercial customers by Motorola before it was made an open ETSI standard. P25 and NXDN are two other commercial voice modes that have started to see adoption by the amateur radio community as commercial users generate surplus equipment as they adopt newer equipment.

While the numbers of deployed P25 and NXDN repeaters combined equals a microscopic 6% of digital voice repeaters globally, both modes showed promising repeater growth.  P25 repeaters increased 19.1% and NXDN grew 13.3% in the last year.

While these two modes still only account for 525 of 8305 repeaters globally, this is interesting because only commercial new or surplus equipment is available. An HVDN prediction is that these two modes will continue to erode potential D-Star growth as most amateurs seek to experiment with easily obtainable and low cost equipment that has a professional or multi use appeal.

The Kenwood NX-5300 is a analog FM, DMR, P25 and NXDN radio
 made for the commercial market but is starting to show up on E-Bay.

Further 2019 digital voice expectations

While this update focuses on repeater growth, it is getting harder to avoid talking about hotspot devices.   The cost of single or semi-duplex devices thanks to open hardware and software initiatives has continued to trend between $30 to $70 USD which offers an opportunity to those looking to experiment with digital voice while mobile or at home when a repeater is not reachable or even available.

Duplex hotspots are like miniature repeaters as Joe N1JTA referred to them as in his presentation given at the Trenton Computer Festival earlier this year.  Much more about learning how to run a wide area digital repeater can be learned from these devices, especially as it relates to DMR and its unique "two discussions, at the same time, on the same frequency" capability.

Costs for duplex hotspots have remained in the $60 to $150 USD range and will likely hold steady for the foreseeable future.

While the original OpenSpot device continues to be a favorite of digital mode enthusiasts, the next generation OpenSpot 2 fell way short of expectations based on its cost, poor Wi-Fi performance and lack of portable power option.

A well known Chinese ham known as Winters CN, BI7JTA has been an active contributor to the advancement of open hardware for a while now.  He has recently introduced a new product that is very exciting in that it solves all negative aspects of the OpenSpot 2 and at a lower cost.
As a finished product, its likely going to be popular as more people learn of it. Since it also is based around common footprint boards, it can be further enhanced by replacing its MMDVM boards with those of even higher quality by engineers like N5BOC and his popular products.

With Alinco and Anytone becoming two of the more popular vendors compared to TYT and Ailunce of last year, probably the most anticipated new digital voice equipment soon to enter the market is the Anytone D578 mobile.

This radio has many common features as the Alinco, Anytone and BTECH hand held radios but introduces something that will be a first for the amateur radio community.

A full control bluetooth remote microphone with display will help set this radio apart for those looking for "remote head" capable radios but with an easier to install approach.

Digital Voice:  Looking Forward

DMR looks well positioned to continue to dominate digital voice interests in amateur radio, but may be challenged by P25 or NXDN if vendors like Icom or Yaesu decide to leverage expertise in the commercial business lines and introduce them to the amateur radio community. Alinco who is the only large amateur radio vendor to offer DMR product to amateurs, but also has a range of commercial products that supports NXDN also.

Features such as location sharing, text messaging and infrastructure enabled intelligence continue to be explored

Wednesday, April 03, 2019

Timing Is Everything: 7 Days With Kerberos SDR

The long awaited Kerberos SDR arrived last month, but I only recently got a chance to really focus my full attention on this unique device this past week. This article covers my first impressions plus setup helpful tips.

What is Kerberos SDR?

A successful Indiegogo campaign which netted 8007% backing sort of is a big deal in my mind and makes for a nice introduction statement.  The Kerberos hardware and software package was under development for some time and required many people to be involved as covered in a past article in the HVDN Notebook focused on tracking radio signals this past November.

Software defined radio has been top of mind in the hobby community for some time, thanks to inexpensive USB TV tuner dongles that have found a dual purpose as wide range radio receivers, such as the RTL-SDR v3 or NooElec and its various offerings for around the same price.

The Kerberos SDR is at its core, four of these inexpensive and capable SDR receivers assembled into one circuit board along with a number of modifications and upgrades to enable some interesting applications.

As the title of the article implies, timing is everything. At the core of the Kerberos is a shared TCXO clock source which ensures all four independent receivers are synchronized with a high degree of stability.

Last month at TCF, Joe N1JTA showed how important a TCXO is to the MMDVM "hot spot" boards that amateur radio operators are using as part of modern digital voice communications.  This same concept applies with the Kerberos, but essentially on steroids.

Having synchronized receivers allows some real fancy computations to be made using newly created open source software that is packaged with the Kerberos SDR.

Computational you say?

There is an already a well written and detailed quick start guide for using a ready made disk image or how to install the packages and related dependencies to get the Kerberos SDR software up and running, so no need to rehash that here.  But, in order to get the most out of this phase coherent software defined radio receiver, here are a few tips.

     Hardware related

  • Power source considerations:  Just like with the MMDVM Pi-Star hotspots, DO NOT use some old 500 mAh USB charger from an ancient Palm Pilot!  The Kerberos SDR needs its very own 2 amp or higher current USB power source that will connect into the USB C port. This is to power all 4 receivers and not for data transfer.  A best practice is to use a separate power source for the Kerberos SDR and another for the single board computer running the demo software.
  • Connecting things together: The order you connect things together does matter.  Follow these steps to avoid frustration. First, connect your power source to the Kerberos and let it run for a minute or two.  DO NOT yet connect antenna or USB micro cables to the SDR.  If you peak carefully inside the SDR near the USB connectors, you will see white LED and blue LEDs flickering inside to tell you the Kerberos is powered up.  Second, now it is safe to connect a USB micro cable from the SDR to your compute device. If using the recommended RPI 3B or 3B+,  your third step should be to apply power to the RPI after you have inserted the SD card.  Reasons for this order explained later.
  • Calibration:  Try not to bug some of the innovators like Corrosive from the popular SignalsEverywhere "vlog" with basic questions so he can find some more new cool stuff to tell us all about even though he may not mind your questions.  Perform the calibration using the built in noise source and 50 ohm terminations your Kerberos came with. DO NOT skip this step.  Not only will you learn more about the software in the process, but you will avoid frustration when testing out direction finding or passive radar functionality.
  • Antennae:  You need four identical antennas.  My initial tests were conducted with these small magnetic mount antennas designed for near the 70cm frequency band.  The real key is identical antennae, especially for the signal location application.  The passive radar application would likely benefit from one directional and one non-directional antenna instead, thus two antennas only are needed for that application.   It would also make practical sense to source some type of metal plate if using magnetic mount antennas, so be sure to order an iron pie plate from Amazon too when ordering antennas if you do not already have one handy. Placing magnetic mount antennae on a ground plan makes a huge difference.
  • Temperature:  If you have already experimented with single SDR dongles, you know they get a little hot.  The Kerberos SDR will also run warm to the touch and is normal. If using the SDR for an extended period of time, you may want to invest in a small fan to keep it cool. 
  • Raspberry Pi:  The image provided on the quick start page is for the RPI 3B or 3B+.  It will not work correctly with an older Raspberry Pi, so save yourself the trouble. The software is also somewhat intensive, so either run the Kerberos on an RPI3 or a real computer. DO NOT try to use an older SBC or anything not supported that is under powered from a CPU perspective. 
  • Taking Kerberos SDR apart:  You will be tempted to take Kerberos apart. DO NOT do it unless you have a good reason to do so.  The 40 pin header under the Kerberos is an alternate way to connect a RaspberryPi with an extended header, but is really not needed.  If you did want to do this, you WILL need to open your Kerberos up and remove a 2 pin jumper inside after almost total disassembly.   Also, that tempting regular size USB port is for future use and will not work UNLESS a pair of chip resistors are removed inside the Kerberos SDR.  The bottom line is, just focus on how Kerberos is configured before thinking about hacks and modifications and get the most out of the hardware as it arrived to you first. 
      Software related
  • Demo software:  Its not very polished, but gets the job done.  The biggest thing to be aware of is that your Kerberos WILL NOT work if you did not plug in everything correctly first.  If you see no sample rate with numbers being displayed in milliseconds or seconds, you did something wrong or do not have the right power source or good USB cables.  Do not blame the software first, check your hardware. The software is otherwise pretty straight forward.
  • Computational stuff:  You may learn quickly that the RPI 3B+ is under powered at times if you are running wider bandwidth than the default setting of 250 kHz. You can trim this down closer to the width of the signal you are interested in.  You can also change the decimation from its default to any higher number for slower sampling speeds. Both changes will give you lower latency overall.   Same goes with shutting off the spectrum display as it does take a number of compute cycles to visualize 4 simultaneous views of the frequency being monitored. 
Additional stuff

There will be future articles about direction of arrival and passive radar related topics here on HVDN Notebook related to the Kerberos SDR as well as experiences running the demo software on a much more capable piece of computing hardware, but for now follow all these tips and best practices.

Feel free to share your experiences on the RTL-SDR forum for Kerberos SDR and enjoy your new toy. 

Tuesday, March 26, 2019

Presentation: Digital Hotspot Pi-Star MMDVM Hardware Overview

Joe N1JTA gave a presentation as part of a workshop at the Trenton Computer Festival on March 23rd.

Billed as the world's oldest computer festival,  TCF19 was the 44th year in which many hobbies converged which show how ubiquitous computers and wireless technology has become.

There is more detail about TCF on websites such as Hackaday and the official event website here.

What made Joe's presentation unique was that it focused only on open source hardware and some best practices and purchasing tips to guide newcomers into a less frustrating entry into the world of digital voice amateur radio technology.

N1JTA also focused on how the MMDVM and Pi-Star combination is an excellent learning tool for those interested in deploying a wide area digital mode repeater, but would like to first experiment on a much smaller scale thanks to a digital hot spot.

Check out the full presentation below and hopefully this enables further learning about one of the most modern incarnations of amateur radio.

Saturday, March 23, 2019

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 23,126.7731 MHz of 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.

Thursday, March 07, 2019

Frequency Expansion: Alinco DJ-MD5TGP

The Alinco DJ-MD5TGP can now easily be expanded to receive up to 520 MHz which is helpful to those that live in areas that use frequencies above 480 MHz such as New York City.

After upgrading the Alinco from FW 1.00 to the not 100% publicly available FW 1.04, I decided to try some key commands that did not work before while trying to reach the same frequency expansion results in the past.

Alinco 480 MHz  520 MHz

Given that the Anytone AT-D868UV, AT-D878UV and BTECH 6X2 all share certain design elements as the Alinco this not all all too surprising with the latest firmware update rolled out to the Alinco DMR dual band radio.

How To Expand

Step 1: Hold down the 1 key, PTT and the side button directly underneath PTT while turning the radio on will show "DJ-MD5 TEST MODE" quickly followed by the Alinco splash screen.

Step 2: Rotate the multi-selector knob on the top of your radio to the desired operational mode and then turn off the radio.


Step 3: Your radio now will function as the mode you selected.

Using with CPS

If you read the data from your radio using the "Model" function, it should show which of the 14 options available through the test mode with the latest CPS v1.03.

alinco CPS

Its now safe to start writing a new code plug or importing channel data again back into your radio.

Please note that you will need to inhibit or enable the transmit function on a per channel basis per your legal requirements.

Enjoy your new "receive" capability if you were looking to access frequencies above 480 MHz with a much smaller DMR capable radio compared to the Anytone or BTECH models.

Looking for interesting discussion about getting the most from digital voice communications?  

Check out for details

Friday, February 22, 2019

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.

Thursday, February 21, 2019

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:

The next HVDN meeting will be on March 11th at 6:00 PM in Rhinebeck with location details at . 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

Thursday, February 14, 2019

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.

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

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

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