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Tuesday, December 04, 2018

64 Satellites: Can I get a ride too?

T- Minus     10...9...8...7...6...5...4...3...2...1...LIFTOFF!!!

SpaceX was able to put 64 various size satellites into orbit with only one Falcon 9 rocket. The total payload weighed in at 8,800 pounds (4,000 kilograms).

learn about satellites class students
Jerry Buxton, N0JY of AMSAT pictured at the SpaceX launch facility.
AMSAT was responsible for the Fox1Cliff (OSCAR-95) communications
satellite available to amateur radio operators world wide

Payload Details

Of the 64 objects launched on December 3rd,  the amateur radio Fox-1Cliff which is now known as OSCAR 95 is just one of many satellites, so here is the full list of publicly known 60 satellites and basic details, so let's get going.....

amsat satellite amateur radio student space

Lists: We love lists!

Not every satellite was a "CubeSat" which are normally 10cm cube weighing less than 4 kilograms.The largest satellite part of this launch was potentially the 231-pound (105-kilogram) KazSTSAT Earth-imaging satellite.  

There was also the Elysium Star 2 which carries the remains of Robert Lawrence, an African American astronaut was selected for the U.S. Air Force’s Manned Orbiting Laboratory program.

64 satellites launched  AMSAT OSCAR 9

#1 - AISTECHSAT 2: The second in the AISTECHSAT series and is a 6U CubeSat developed by Aistech to provide thermal images of the Earth. It will also help with maritime and aeronautical tracking as a prototype for a larger constellation.

Thermal imaging system is on board that is used in forest management, fire detection, gathering data for agriculture like identifying the health of the plant, analysing land for expansion. It can also detect energy consumption and loss of buildings.

The satellite also provides airborne and maritime vessel tracking via AIS and ADS-B receivers. The AISTECHSAT can also use a bidirectional communication system on board to send and receive automatic information from the vessel or remote asset worldwide.

For aircraft tracking an ADS-B receiver is on board. HVDN has its own ADS-B receiver that tracks aircraft in the Hudson Valley and is available to its membership. More information can be found here


#2 - Astrocast 0.1: Astrocast is a planned network of Nanosatellites providing global L-band machine-to-machine (M2M) services. The satellites are orbiting in a low earth polar orbit. This allows the creation of a global network covering the entire globe, including the poles. 

After integration of the NanoLink terminal, the ground based assets can reliably and securely send any kind of sensor data to the constellation of nanosatellites that will acknowledge the reception. Astrocast enables transmission of 1KB/day from any region on the earth.

A geographically distributed network of ground stations collects the data gathered by the satellites. The data are then uploaded to a cloud storage for access by the customer.


#3 - Audacy:   Audacy is building a space-based data relay network via a constellation of medium Earth orbit relay satellites along with our ground facilities. These satellites will maintain constant connectivity for our customers’ spacecraft from any point on Earth to lunar orbit

Details on 59 more satellites

Fantastic research has already been done by Gunter Krebs on all the other satellites that were part of this historic launch.  Have a look at all his hard work at
Add caption
Talk about stuff like this?

Care to talk with others interested in satellite communications and technology plus the experiments conducted up above?   Here are some spots to check out related to amateur radio:
  • AMSAT DMR Talk Group:  98006 (Listen in here)

Monday, December 03, 2018

Review Update: New PicoAPRS Model(s) & Firmware Update

Lately it seems the only attention APRS has been getting is if and how it is implemented on new DMR radios.

This is not fair, so let us look at some dedicated APRS only devices compared to some radios that offer location and message sharing capability.

PicoAPRS product is the smallest
APRS transceiver on the market

Location Finding: Different devices for different people

Automatic Packet Reporting System (APRS) is a technology 20+ years in the making that lets amateur radio operators use low speed data over narrow channels to share location and basic text status updates in a few formats.
Cool Thing:  It is also possible to use APRS for telemetry data, such as weather information or malfunctioning equipment status updates. APRS can also be used to track things, like a rocket or a balloon. This is the Amateur Radio version of "Internet of Things" before that was even a term.
Ham equipment vendors Yaesu (Fusion), Kenwood and Icom (D-Star) all offer different digital voice mode radios and none are DMR products which is the most popular digital voice mode today.

Pictured Left to Right  - Kenwood TH-D74, Xiaomi Mijia,  TYT MD-UV380, Alinco MD-5TGP, Mobilinkd TNC2 and PicoAPRSv2
Pictured Left to Right - Kenwood TH-D74, Xiaomi Mijia,
TYT MD-UV380, Alinco MD-5TGP, Mobilinkd TNC2, PicoAPRS

Vendors such as Anytone, TYT, Retevis and Alinco support the ability to send GPS data that can appear on the website, but this is not really APRS in the traditional sense, but some call it D-APRS.
Hot Stuff: A good comparison of APRS to another form of location sharing was done from a hot air balloon this summer.

Location Battleground:  Get ready!!

Beyond amateur radio which is a licensed radio service globally, there are now unlicensed radios such as the GoTenna, Xiaomi Mijia and Motorola T800 that allows users to share location data with one another, but are far from as robust as what is possible via amateur radio at any level thanks to APRS but come close and are slightly easier to use as discovered a recent hamfest.

Non-Voice Capable APRS Devices

Two of the smallest and full featured APRS devices that are not voice transmission capable are the PicoAPRS v2 and MobileLinkd TNC2 which have been reviewed in the past on HVDN Review Lens.

The Mobilinkd device is more of an accessory gadget that physically plugs into most any two way radio with appropriate cable.

THe Mobilink TNC2 also requires a smartphone paired over bluetooth that runs an application to send, receive and view location of users or send messages based on the GPS built in to the smartphone. This is sort of messy but is an elegant solution....

APRSdroid application found on Google Play store

The PicoAPRS however is a totally self contained device that is a GPS, data radio and user interface in one even smaller package.

Taner, DB1NTO has made many improvements in his PicoAPRS product since its introduction and that is what we will explore. No smartphone needed or other radio needed!

What is the difference between the PicoAPRS v2 and v3?

For something already really small, Taner made it even smaller in the latest version while retaining every feature and even adding a few things such as a modular battery and even better precision GPS/GLONASS reception.

Can I connect the PicoAPRS to a computer?

Everything can be configured with the two buttons on the PicoAPRS.

If you want to customize a beacon comment, such as "Please call me on 146.520MHz or DMR TG 31630", that takes many button presses.

It is possible to do this instead via a terminal program such as TeraTerm. The otherwise very good PicoAPRS manual is somewhat lite on detail about this, so here are some simple steps for those that are not computer experts.


Connect PicoAPRS to computer:  On the PicoAPRS, navigate to the menu called  "USB Mode" and change it to "Config". Then connect the PicoAPRS to your PC and it should install USB drivers automatically in many cases. If not, this is what you need from Silicon Labs.  

Configure a few things on your computer:  In "Control Panel" and "Device Manager" in Microsoft Windows, you can now see which COM port your PicoAPRS will use.

Now you need to configure TeraTerm by selecting the serial port connection that matches your PicoAPRS.

Next, open up the menu titled "Setup" and go to "Terminal" and configure to be CR+LF and check mark the "Echo" box.  This lets you see what commands you send to the PicoAPRS.

Finally, open up "Setup" again and go to "Serial Port..."  You need to select the same COM port your PicoAPRS is using and set the speed to 115200.  No other setting will work.  It needs to be 115200!!

Now, you are ready.  Press any key or the ? and you should get the below message returned to you which shows what you can configure from the computer with your PicoAPRS

To change the beacon message, just type *C* with your own text after it and press enter

Sidenote on other computer things:  On the PicoAPRS, you can also change the USB settings to give you GPS NMEA data. Go ahead and try it while still connected to TeraTerm. Changing to that mode will let you see something like this:

There are also many other applications that will let you use the KISS-TNC mode for even more advanced things. Some of these include PinPoint APRS and WinLink plus of course the old standby of APRSISCE32 but is not part of this review.

There is also a new "Serial USB" data mode too which has a lot of interesting potential if you want a total stealth data radio to go with you anywhere with your laptop.

Get to the point!!!  All I am trying to say is that the PicoAPRS does a lot more than look like a cute little ham radio toy.

New Feature In PicoAPRS Firmware v10 

While v9 software is the most current as of December 3rd 2018, v10 is not far away and will add a status message function in addition to beacon messaging.  This gives you two different types of status updates sent at different intervals from the PicoAPRS.

The new firmware will be available around Christmas time 2018 along with a new and even smaller product from Tanner called PicoAPRS Lite which is designed for use with airborne payloads.

Please keep an eye on his website for more detail at for the new firmware, details on the v3 and the upcoming new PicoAPRS Lite product.

Monday, November 26, 2018

Power Pole Connectors: Why they are good to have

Electronic hobbyists know all too well that there are different types of connectors for specific intended (or unintended) applications.

Special HVDN Cyber Monday discount offer below this article

The Power Pole connector type is very helpful to have on hand. Here we will explore the correct way to install them and a few different uses for these genderless connectors across the "amateur radio", "maker" and "electronics hobbyist" communities.

What Is A Powerpole Connector?

The "Powerpole" is a family of electrical connectors originally brought to market by Anderson Power Products (APP),although plug compatible connectors are now available from alternate sources.

Specific variants of this series of connectors have become de facto standards for conveying "higher power" direct current (DC) electrical power, although these standards are inconsistent and sometimes ignored.

There are two parts to every power pole connector, the housing and terminal. There are also spacers and pins for even more potential covered later.

The Basics:  Powerpole Terminology

Powerpole housings come in many colors. This is great to help identify different applications such as positive voltage could be red, negative power could be black, a ground connection could be green, etc

The most common housing size also can accommodate different size terminals that can carry 15, 30 or 45 amps of power.

Great Feature: Housings can be used over and over by removing the inner terminal if you need to change to a larger size or different color.

Many other connectors that are crimp based can not be easily reused and this is a major benefit of powerpole connector housings.

It is a best practice to purchase extra terminals to have on hand if you crimp one poorly or eventually need to replace the terminal.

Powerpole terminals rated for 15, 30 and 45 amp also accept different diameter wires. Never try to use thicker wire in smaller gauge terminals, but it is ok to use smaller gauge wire in larger terminals.

Good advice for many amateur radio or robotic applications is to use the 30 amp #12 AWG as your standard size terminal.  Only very high current applications will require the 45 amp terminal versions and those are more expensive, thus better saved for those applications only.

Mating Powerpoles Together

The outside of the powerpole housing has special grooves that allow them to slide together and create a power pole block. There are four different ways each powerpole housing can mate together and every application may have different needs, so there is no uniform standard by design to promote different use cases.

Many applications in amateur radio involve power pole connections for DC power, the recommended way to assemble them would be RED on the LEFT, BLACK on the RIGHT with tongue down and hood up as pictured below.

The housings friction fit together are often very tight and not likely to pull apart, but there is also a small pin that can be inserted between housing to ensure the housings do not pull apart.

Since the power pole connector is genderless, meaning there is total uniformity and no male or female version it is sometimes necessary to flip the colors from one side to the other so a pair of connections can fit together.  Always assume that a RED powerpole connected to the end of a RED wire is positive DC voltage, never connect RED to BLACK and BLACK to RED.

Powerpole connectors have been gaining in popularity over the last 10  or more years. Something new is a polarized spacer to even further prevent accidental connections. These work in different ways, so sliding them on to sensitive equipment power cables may be a good thing to consider.

One of many new powerpole products offered at Quick Silver Radio 

Premade Powerpole Cables and Accessories

A specialized crimping tool is the best way to assemble your own power pole connections rather than generic pliers. It is also possible to crimp and solder terminals for even better reliability, but not mandatory.

There are many preassembled accessories like jumper cables,  12V accessory panels, and mounting kits to make using power pole your go to DC connector of choice.

Non-Power Use for Powerpole connectors

There are many other uses for these almost "Lego-like" power connectors that only you can think of. One example is using them as quick connectors for antenna projects such as portable linked wire dipoles for those interested in SOTA or Field Day HF operation or even to help make ladderline easier to splice used in other antenna projects.

KK5JY has a good article on using powerpoles
with antenna projects at

How to properly assemble Powerpole connectors

First, start by getting the best crimp tool you can afford. Do not cheap out or try to use the wrong tool for the job.  The result will be an improper connection and false blame on this great connector by not following best practices.

GB Electrical GS-388
A basic powerpole crimp tool

The above pictured power pole crimp tool is pretty basic and sells for less than $15 USD at most retailers. This tool is not the fanciest, but gets the job done and has not worn out since I first purchased in at a hamfest back in 2008 or 2009 and has performed flawlessly.

A basic crimp tool compared to the fancier ratchet function ones take a little more time but I think provides a better crimp, but that is just personal opinion as I have both types of crimp tool.

basic powerpole crimp tool
A basic crimping tool gives a little more control over
the finished result, but does require a little more hand strength

Here is a great video on how to use the ratchet based tool. There are many more just like it, but this seems to be the best one showing proper process thanks to the Riviera Robotics Team of Santa Barbara, California no where close to the Hudson Valley of New York.

Special Discount Offer:  Thanks to Quicksilver Radio

John Bee, N1GNV and his team usually make it to most every decently sized "hamfest" in the North Eastern United States where they sell not only power pole related products, but many other tools, small parts and radio related accessories. Now you can take advantage of some savings with your next online purchase at Quicksilver Radio on Cyber Monday (Expires 11/27/2018)

Please use the following coupon code on your next purchase to appreciate some savings on your next purchase of power pole related equipment.

Tuesday, November 20, 2018

How was it? Poughkeepsie Mini Maker Faire

The recent snow and damp conditions did not stop the crowd from making it to the Poughkeepsie Day School on Sunday November 18th to participate at the Poughkeepsie Mini Maker Faire.

So many people actually arrived, a shuttle bus needed to be arranged at the last minute to ferry guests from a not too distant parking lot at the local Boardman Library back to the event site.

Poughkeepsie Day School Puma - the official mascot of
both the school and the 2018 Poughkeepsie Maker Faire

The 2018 Poughkeepsie Mini-Maker Faire: What you missed

The official event was from 10:00 AM to 4:00 PM, with sponsors and demonstrations setting up before 9:00 AM, including the goats, llamas, chickens and rabbits! 

Eager human attendees were outside before the official start time and there was a steady trickle up until 2:30 PM. 

Lets make some cheese and memories with
 the goats from Sprout Creek Farm

Attendees had a chance to make cheese from goat milk,  spin yarn from locally sourced organic fiber and also make robots.

Outside in the parking lot were a few gourmet food truck to help keep stomachs almost as full as faire goer craniums during such a well organized and educationally rich event.

Mini Maker Faire has been taking place for a few years in Poughkeepsie.
Here is a photo from 2015 attendees using microscopes to view interesting things.

Members of the local makerspace called Squidwrench invited Hudson Valley Digital Network to help with the soldering demonstration where each willing participant was going to create a commemorative blinking LED light badge for workshop attendees to take home.

Correct temperature control and soldering of an LED

There were only 150 LED badges that were going to get built and with 5 soldering stations setup, every station built between 20 to 40 each and all but just a few of them being assembled by children between the age of 7 and 13 years old.

Using a 1000x microscope, it was possible to view the inside of
common LED lights found in many electronics and the badge
being assembled thanks to Squidwrench and Makezine.

Each of the multi color blinking LEDS contained 8 separate and different colored light emitters. A high power digital microscope that Hudson Valley Digital Network uses to take photos of circuit boards for some of our articles was used to show children what the inside of the LED looks like and how sensitive they are if too much heat is applied when soldering them to the board.

A damaged LED from too much heat while being assembled.

It was amazing to see how much interest everyone had with soldering and seeing what else can be viewed with the microscope.

One father who works as a design engineer for a semiconductor company and his two children even had a look at the fine details of fingers, including the dirt discovered that will make sure his little guys will always wash under fingernails from now on. 

Another young man and his brother each wanted a badge and one for mom and dad. Both were asking about how hot the soldering iron got, how much it cost, what else it can do and if it can melt other things other than solder. 

One of the last badges of the day nearing final completion

Demand was so great that Squidwrench ran out of badges and had to tap into private stocks of components to finish a few badges and even repair a few where makers got a little to enthusiastic. 

One maker got a special blue LED that looks like a Lego building block since the normal blinking LED got damaged during construction.

A member of HVDN and his daughter helping others
assemble the Squidwrench provider Maker Faire LED badges

It was a great day that brought a lot to the community and helped raise awareness of what goes into making and playing bagpipes, puppetry, how to care for animals and so much more not just related to electronics.

For anyone interested in purchasing the same digital microscope used at the Poughkeepsie Maker Faire, please have a look at Quicksilver Radio which is where the microscope was purchased while attending the Deerfield Nearfest and New England Tech Trek reviewed in a past article on HVDN this past October.

FLASH NEWS:  An upcoming article will include a special discount code for purchases made by HVDN follower on the Quicksilver radio website
Learn more about upcoming Maker events at

Monday, November 19, 2018

Basic Overview: Tracking Radio Signals

Finding the source of a radio signal is sort of a fun thing to do for the modern electronics hobbyist.

Confirming the location of a local FM band music broadcaster, amateur radio station or even your cell phone and maybe your car keys is possible with relatively inexpensive equipment since they all transmit RF energy!

With the much anticipated KerberosSDR nearing availability, which will provide unique radio based location capabilities.

Something unrelated recently reminded me to go back to have a look at RTLSDR_Scanner and its latest developments since it offers a lot of great functionality for those interested in radio signal location options available today.
Both solutions use a software defined radio or SDR rather than a traditional radio. This is one reason that makes both of these solutions really exciting!
The conclusion of this article will show you how to generate a map such as the one below that will show signal/power measurements called an "RF Heat Map" using RTLSDR_Scanner.

Kerbo What?

The well funded IndieGoGo campaign of the phase coherent software defined radio that Carl Laufer of the excellent blog, the design team behind the now named Othernet Project and Tamás Pető who is studying electrical engineering at Budapest University.

This trio has created something that will be able to do some amazing things, but let's first take a look at basic radio signal location theory and another modern radio signal location tool.

What is phase coherence?

Let's first look at some basics of radio signal location through some easy to understand math.

If two people (1 &2) knew exactly how far apart they were  (A) and had directional antennas that could help find the maximum signal strength of a transmitter (3), they can use the angles of the signal direction and the known distance between them (A) to guess pretty closely on the approximate direction and distance (B&C) of the signal source (3).
This method of signal location is called triangulation.Radio signals travel at about the speed of light which is about 982 million feet per minute. 
If our two friends standing at location 1 and 2 had identical and synchronized clocks and had radios tuned to the frequency of the transmitter at 3, they could also determine the direction of the signal by moving around a little to see how the signal strength fluctuates, they could also determine the general location of the transmitter with a little more help by use of doppler theory.

Doppler works by sensing how a received signal's frequency (2) fluctuates up or down based on the speed it is traveling and how long it takes to go from source to receiver (1). with multiple antennas (A,B, C, D) .

If multiple receivers/antennas are used at the same time, the difference in time it takes to be received at each can be used to calculate a direction of the signal.

Some form of very fast analog or digital computing and comparison that is part of the receiver is needed since we are talking about nano or millisecond differences.

Phase coherence combines theory behind the speed of which radio signals travel against a known time source along with triangulation in order to find where a signal is coming from.

Police departments have been using a phase coherence system to locate stolen cars for many years called LoJack.  

If you look closely at the roof of the New York State Police cruiser above,  the four antennas on the roof spaced in a square pattern roughly about a foot apart help perform the triangulation and time difference of arrival (TDOA) measurements to quickly locate the stolen vehicle. 

All the police officer generally needs to do is view a display not too different from a no longer in  business company that offered a device called the Ramsey DDF-1 Doppler Direction Finder.

The doppler method of signal location involves the ability to visualize the arrival angle of signals relative to one another of equally spaced antennas through the use of a series of LED lights spaces in a circle pattern.
A special circuit compares the received signal strength at each of four antennas relative time or direction of travel in order to give the direction towards the signal
As the police car travels, the LED lights would blink in the direction where the signal is coming from, if it is in one location. This would tell the officer (or amateur radio operator) which way a signal was coming from and they could try to get close to its location.

Once close enough to a signal, other methods could be used such as a field strength meter to find the smallest of hidden transmitters or chopped out hidden LoJack units. 
Twenty or more years ago, doppler based analog solutions were almost as fancy as one could get in locating transmitters.

In 2018, however, things have come a long way thanks to SDR and even embedded computing devices like the raspberry pi, which can also be used to run RTLSDR_Scanner and the KerberosSDR.

Heat Maps and GPS

The RTLSDR_Scanner application is a little more simple than KerberosSDR. An inexpensive software defined radio (SDR) receiver along with a GPS USB dongle can be purchased together for less than $40 USD.

KerberosSDR, is essentially four SDR's combined into one unit, so should also be able to use the RTLSDR_Scanner software too.

The SDR and GPS along with one antenna, a computer (laptop or Raspberry Pi) and the appropriate software can perform some interesting signal location applications.

GPS provides the function of providing accurate location of the receiver along with a stable time reference.

The locations coordinates, exact time and signal strength of the signal can be combined to provide stunning visualizations of how strong or weak a signal is on mapping programs such as Google Earth

Lets get SDR_Scanner working

In 2016, this program was only operational under a linux computing environment, so was not easy to set up unless you were very involved in computer "stuff".

This program has been available as a much easier to install Microsoft Windows version since last year and is finally what this article is about!

You will need the following hardware and software along with a little patience and clear mind.

  • SDR dongle (Suggest the RTL-SDR v3, but pretty much any will work)
  • USB GPS with NMEA output (Suggest the uBlox7 Gmouse)
  • Modern Windows Computer (Meant to run Win7 or later!!)
  • Antenna for frequencies of interest (Most SDR come with a basic antenna or add on options)
First, lets make sure your SDR receiver is functional.  The best tutorial on this can be found here.  
Step 1:  Get your SDR working: 
Try listening to some FM broadcast music between 87-108MHz,  weather broadcasts in the 162.4 to 162.6 MHz range or for local amateur radio or business/first responder activity between 420-500 MHz.

Now, let's get your GPS working

The USB GPS should automatically recognize and install drivers for most people on a Windows 7 or 10 computer.

After installing the ublox center program and just playing around with it to show it can receive location data, make a note of what COM port the GPS has decided it will use. 
Note:  The GPS obtains a virtual serial port over USB. You DO NOT need any outdated USB to 9 Pin serial adapter.

The instructions for getting RTLSDR_Scanner are cracking fantastic, so give them a read here and you should be up and running fairly quickly
Step 2:  RTFM = RTLSDR_Scanner Instruction Manual

Try tuning to local weather or music broadcasts to see what activity looks like in a one megahertz wide segment would look like.

The above image shows from 162 to 163 MHz, with a very powerful signal located at 162.475 MHz (Local weather broadcast) and how the signal fades slightly over just a few seconds from 12:04:19 to 12:15:50 due to driving around at a slightly variable speed.

A pinch of GPS and a cup of Google Earth

Now that you have a feel for how the GPS and SDR with RTLSDR_Scanner function, lets combine the two now by enabling GPS data to get combined with RTLSDR_Scanner output.

Below is what exporting the RF signal data looks like over the same 11 minute period when combined with GPS location data as output against Google Earth map.

Step 3: Use this opportunity to install Google Earth if you do not have it already. 

You will need to enable GPS under the "Edit" menu of RTLSDR_Scanner and ensure you change GPS type to "NMEA (Serial)" and select the COM port your USB GPS has.

When everything is configured correctly, you can use RTLSDR_Scanner to show what GPS satellites are being received and also when you get a location lock, your GPS coordinates and altitude will appear in lower right part of the application.

All that is left now is to go drive (or walk?) around with your laptop and start taking some measurements.

Depending on the refresh rate (dwell setting) and resolution (FFT Size setting), the output image on Google earth may vary.
Helpful Note:  Be sure to set mode to "continuous" and not try to sweep too wide a frequency range. Keep it to the smallest based on the signal you are looking for.  YOu also need to indicate how many sweeps to perform or otherwise, it will just keep overwriting the previous sweep which is not very valuable. The minimal setting is 1 MHz. This will help create the best results viewed on the map. To generate an the images in this article required 115 continuous sweeps.

Major benefits with RTLSDR_Scanner 

Here is a list of possible real life user cases that this application will enable:
  • Creating a coverage map for amateur radio repeaters in the 144, 220, 440, 900, 1200 bands
  • Determining general radiation patterns of a mobile or home amateur radio antenna installation
  • General location awareness of commercial radio or broadcasters
  • Interference source location finding
  • Figuring out the range of your garage door opener or other pulsed mode transmissions
  • Basic passive radar system
Sadly, RTLSDR_Scanner is not really designed as a Wi-Fi mapping tool, but by playing around with the dwell setting and using a device like a LimeSDR MiniHackRF One or ADALM Pluto which are more expensive could give interesting results.

These other SDR options can go to about 6 GHz and not covered by the inexpensive SDR dongles that usually do not go too far past 1.9 GHz plus monitor wider bandwidth of up to 30 MHz wide at one time compared to the 3 MHz wide capable RTL SDR v3.

So what is special about KerberosSDR?

For the price of under $150 USD, users will be able to use the hardware and software along with four antennas to generate a heat maps just like RTLSDR_Scanner and also show signal direction using phase coherence theory through new software that Tamás Pető is focused on where an early version is demonstrated here:

Hope you found this article about basics of radio signal location interesting and something to keep you occupied while HVDN awaits its pre order of the KerberosSDR which will then be reviewed here later this winter.

Sunday, November 18, 2018

Teardown: Expanded Alinco DJ-MD5TGP Review

In a short amount of time, the new Alinco DJ-MD5TGP has become an easy favorite by the author. 

After doing a fairly basic review that highlighted the programming software as one great feature compared to other DMR radios, I thought it would be good to continue onward with an internal review much like the two part teardown for the TYT UV-380 a few months ago.
Do your own review? If you would like to download Alinco CPS 1.1 for the Alinco DJ-MD5TGP, you can do that here since it is not yet available on the Alinco website. 

Alinco MD5 review DMR hand held
The Alinco DJ-MD5TGP is priced to sell and is feature
packed and few of early launch quirks like many other
competing DMR hand held amateur spectrum capable radio

Some Additional Review Thoughts - External Feelings

Before we dive in with some internal photos and details, here are some additional thoughts on why this radio is earning high marks in my opinion. 
The Good: Alinco DJ-MD5TGP Display -  At 1.7 inches every bit of information on the color display is well thought out and organized. The closest competitor to the Alinco is the Anytone D868UV and newer D878UV.  
Many features made famous by the various aftermarket firmware such as MD380tools and its variants for TYT or Retevis radios certainly provided inspiration for Alinco.
The only non-DMR radio that would even compete is the $500 Kenwood TH-D74, so for between $170-$190 for the Alinco - you get a lot of thoughtfulness in display layout design.
Alinco DJ-MD5TGP on default level of brightness
showing a typical level of DMR information

The Good: Alinco DJ-MD5TGP Side Buttons
- Besides the PTT button on the left side of the radio, there are two others.  
Both buttons can be reassigned for too many combinations including a separate function based on a long press or short press, so technically its like having four buttons just like many larger radios. It is also possible to lock out both side buttons which is potentially a nice feature.
The Good: Alinco DJ-MD5TGP Connectors - At first, a thought on the change to the SMA-J reverse polarity antenna connector was going to be annoying and force me to rethink all future antenna or connector purchases. 
.... ...- -.. -. .- ..- -... ....
Author Perspective: I think I now understand this is a beneficial connector and not a cheap option that has been found on all the inexpensive "Baofeng" type of radios plus few others that are more premium like the Ailunce HD1 and Anytone D868/D878.  The common SMA Female as it is known on radios like the Icom ID51, Yaesu FT2DR, Kenwood TH-D74 may be the last of that generation to make way for more SMA-J style connectors on hand held radios.
.... ...- -.. -. .- ..- -... .... 
This antenna connector seems like it will prevent potential stress fractures that happened with the MD-2017 connector and anyone who has ever "accidently" dropped a radio.  
While the antenna connector is the same as other non-Yaesu, Kenwood or Icom radios, I welcome the change back to what I think of as standard mic/ear connections. 
Important: The larger 3.5mm plug is for speaker and the 2.5mm is for microphone. 
The benefit with this is having easy ability for most standard headphones to plug in to listen to music via the FM broadcast function or to any other frequency the radio is capable of receiving.  This was standard until opposite became standard, so now we are going back to the old ways. Make sense?  Have a look at Radio Shack HTX-202, Icom W32, Alinco DJ-496 plus other radios of that vintage to better understand.
Alinco DJ-MD5TGP outer casing removed to show GPS
antenna placement, waterproof covering for volume
and channel knob and SMA-J antenna connector

A Baofeng, Kenwood or Retevis microphone will
not work with the Alinco and that may be a good thing
The most exciting option on this radio is the micro USB connector found on pretty much every smartphone aside from the latest USB-C based options like the Google Pixel 3 or Samsung Galaxy S9. This makes future replacement super convenient and inexpensive. 

Standard USB cable for the Alinco, just like the Kenwood TH-D74.
Will all radios soon have common programming cables?
The Good: Alinco DJ-MD5TGP Sound -  Audio for such a small radio is loud and not overdriven. As we will see in the tear down, the keypad is essentially in front of the speaker and microphone holes which saves on space to make this a compact and sturdy radio. 
The Good: Alinco DJ-MDTGP Super Features -  There are many cool functions found in this radio, but I am only going to mention two here that may relate to what we will also see in the teardown.  
One is the ability to monitor (listen) to both DMR time slots on the same frequency at the same time thanks to the "Digi Monitor"  function with "Double Slot" enabled. 
This can be off and single slot - which is like "promiscuous mode" or "Group Match Off" found on other radios. 
Pay Attention!! A function like this makes it possible to never, EVER miss any DMR communication on one frequency when "Color Code" is set to the "Any" function.    
This is great if traveling or wanting to casually monitor, but this feature may get annoying if there are two different discussions taking place at the same time on different time slots since the audio on both is at the same level. 
The second super feature is almost laughable, but allows you to customize the maximum receive volume level. Setting a low level gives greater range of control across the entire rotation of the volume knob. This feature helps solve some of this sort of issues with digital audio that is hard to have good automatic gain control (AGC) to solve.
Teardown Key Points

The following sequence of photos include comments as to the "internal" impact on what makes this radio unique. 

The only other radio that is considered the most popular DMR radio is the Anytone D868/D878 which is roughly the same size as the TYT 380 style radios or re-branded Retevis options.   There is already a decent teardown of the Anytone D868 here  and here which we will learn has some similarities to the new Alinco and possibly even more with the new Anytone D878, including the screen and layout.  

Do better features come in smaller packages? 

Behind the front cover PCB

Alinco has seemed to engineer this well and may not suffer this issue as found on older keypad designs.  All buttons are interspersed with the speaker grill opening. The speaker is behind the button overlay.   

Note the GPS antenna positioned at the top of the display which gives it excellent reception compared to the TYT MD-UV380 and MD-380G which uses the identical antenna, but poorly positioned.

Rear of behind front PCB

Two springs contact the speaker from the bottom main PCB and a multi pin connector completes further connection for the keypad and display. This is much better design than ribbon cables that have proved a fault point in main other radios or short soldered wires for the speakers which can be easily broken. 

Front of main PCB

The front side of the main PCB shows the springs and connector that mate to the front PCB.  The large RF shield covers the "front end" of the radio which helps create a receiver that suppresses any internally generated noise. 

A smaller RF shield towards the bottom of the front PCB protects other critically sensitive parts of the software defined radio (SDR) heritage of this radio but is not direct conversion based on the multiple TCXO and real time clock (RTC)

Main PCB of Alinco DJ-MD5TGP prior to removal
of RF shield covering the bulk of the RF front end 

Alinco DJ-MD5TGP main PCB with RF shield
section removed to show the L C filtering

Rear of main PCB

The underside of the main PCB of the Alinco DJ-MD5TGP shows some exciting things. First is the properly placed RFPA that contacts the large metal backing of the radio found under the main battery. 

The main CPU for the Alinco DJ-MD5TGP is the GD32F303 which is a cloned version of the ST Micro version called STM32F303. The differences are mostly negligible, but "on paper" specifications list some improvements with this version which also licenses ARM Cortex M3 architecture.

This microcontroller selection may contribute to how Alinco was able to offer the DJ-MD5TGP for the price of $169.99 to $189.99 USD in late 2018.

Also found on the underside of the main PCB are the AT1846S popular SDR chipset used in many DMR radios  Interestingly, the Texas Instruments  very low power stereo audio codec chipset with pretty decent DAC properties is also involved. 

These two chips alongside the main MCU (GD32F303) create some powerful capabilities in such a small package dual band radio.

AT1846S as found in the Alinco DJ-MD5TGP

Texas Instruments AIC3204 as found in the Alinco DJ-MD5TGP

Big Deal:  Dedicated DMR Baseband

We still have not found anything too interesting, but we have yet to talk about the SCT3258 which is a dedicated baseband chip for DMR with built in AMBE3000+ capability. 

This is where the magic likely happens for the Alinco DJ-MD5TGP and may enable interesting future upgrades based on cursory glance at the SiComm specification sheet. 

Finally, we arrive at the RDA 5802 FM receiver chip that offers some music reception capability in this unique radio.

What does all this mean anyway?

There is a lot of interesting engineering involved with the Alinco DJ-MD5TGP which is far different compared to radios like the TYT MD-UV380 and Ailunce HD1.

Many manufacturers today no longer include schematics to help in the repair and possible future modification or improvements that could be made at the hardware level.

Instead, the hardware tools are here and only an interest in further software modification can potentially unlock more functionality with modern radios.

Hopefully this teardown may inspire further curiosity in this Alinco radio to educate a buying decision or even the possible eagerness to intentionally void a warranty to poke and prod around the inner workings of this fascinating radio.

The final image to share is that of the ATGM336H GPS chipset.

Basic Bill of Materials 

Use this handwork to estimate the bill of materials for this radio based on these highlighted chips and determine if the Alinco DJ-MD5TGP is a good value or not.

I think you may find this latest radio by Alinco represents the best of a modern digital amateur radio as of November 2018 and it will be interesting to see what is the going to be the next big advancement in amateur radio hand held radio offerings.

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