Traditionally we’ve seen radio direction finding (RDF) in the form of Doppler kits and tone meters, however with the proliferation Software Defined Radio (SDR) we’re seeing a new form of direction finding.

Essentially if you take four software defined radios and coherently link them together, you can then compare the signals from four separate antennas to get a bearing of your target signal’s location.

I recently came across a project on Indigogo which offered this in a complete package called the KerberosSDR. Here is a video of my setup and a demonstration of this radio.

https://www.youtube.com/watch?v=n5aWrz-42qc?rel=0

The KerberosSDR is still under development, but from my tests it works fairly well. Unfortunately, I don’t have any traditional RDF gear to compare it to but from what I’ve seen it’s certainly a potential way to go if you’re looking to have some fun with RDF and want some more modern gear.

If you’re interested in the KerberosSDR, you can find more information about it here:

https://indiegogo.com/projects/kerberossdr-4x-coherent-rtl-sdr

Stories you’ll find in our April, 2019 edition:

TSM Reviews: Uniden SDS100 Base/mobile Scanner
By Larry Van Horn N5FPW

On the heels of the release of the SDS100 handheld scanner in the first quarter of 2018, Uniden announced the release of the SDS200 base/mobile scanner in January 2019. Like the SDS100, the SDS200 is a True I/Q™ scanner, that incorporates software defined radio technology to provide improved digital performance in even the most challenging RF environments.

What sets the SDS100/200 series scanners apart from any others in the marketplace is their ability to handle simulcast reception issues while monitoring certain P25 trunk radio systems. Larry takes a look at this talented scanner in part two of “The Good, the Bad and the Ugly.”

Bringing Ham Flavored STEM into the Classroom
By Martha Muir W4MSA

Members of the North Fulton Amateur Radio League (NFARL) spent a week working with some seventh and eighth grade students at Mill Springs Academy in Alpharetta, Georgia, teaching them some fundamental concepts of electronics with direct applications related to amateur radio. This is part of a program at Mill Springs called Winter Learning, where students get to take a weeklong seminar on a specialty topic. This specialty topic, “Electricity is Magnetic!” was organized by NFARL members, Chuck Catledge AE4CW and Jim Stafford W4QO. Martha tells us what happens when Science Technology Engineering and Mathematics meets amateur radio in the classroom.

Portable Airband Transceiver Overview
By Cory GB Sickles WA3UVV

The VHF spectrum is full of FM analog and various forms of digital voice and data communications, but also found there are communications based on a technology that goes back a century and then some—AM or Amplitude Modulation. This is the type of signaling shared by commercial and general aviation pilots, as well as the men and women on the ground that communicate with them to keep everyone safe and moving efficiently. If you live near an airport of any size you may have wondered about listening in. Cory takes a look at listening to this small but important slice of the spectrum.

Othernet’s Free Satellite Service Continues to Evolve
By Kenneth Barbi

The free one-way digital satellite service, known as Othernet, has been evolving since its debut in 2017. Othernet had operated first on Ku-band and then on L-band, and though coverage was worldwide, the cost was astronomical, and the throughput was limited to 20 MB per day. By reconfiguring their operation back to Ku-band, costs came down and throughput increased to more than 1 GB per day. But the change required different hardware. Kenneth updates the latest on this non-profit information service.

Scanning America
Dan Veeneman
TETRA System; FCC Actions; Clark County, Ohio

Federal Wavelengths
By Chris Parris
Federal Radios Fading Away?

Milcom Monitoring
By Larry Van Horn N5FPW
Monitoring the Pakistan-India Navies

Utility Planet
By Hugh Stegman
North Korean “Numbers” Messages Continue

Shortwave Utility Logs
By Mike Chace-Ortiz and Hugh Stegman

VHF and Above
By Joe Lynch N6CL
ISS Astronauts are Calling CQ Students

Digitally Speaking
By Cory GB Sickles WA3UVV
Split P Soup

Amateur Radio Insights
By Kirk Kleinschmidt NT0Z
Down to the Wire

Radio 101
By Ken Reitz KS4ZR
ATSC3, 4K and 5G: What Next?

Radio Propagation
By Tomas Hood NW7US
A New Cycle is Born

The World of Shortwave Listening
By Rob Wagner VK3BVW
Hunting Shortwave Schedule Changes

The Shortwave Listener
By Fred Waterer
Slovakia on Shortwave, RNZI, Plus BBC Programming this Month

Maritime Monitoring
By Ron Walsh VE3GO
Winter Winds, Spring Melt and Radio

Adventures in Radio Restoration
By Rich Post KB8TAD
Still a Thrill: The National SW3 “Thrill Box”

Antenna Connections
By Dan Farber AC0LW
Well Grounded: A Down to Earth Station

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Prologue…

I was born in 1932, which by definition made me a depression baby. This episode in the life of Urb the emerging nerd, demonstrates that people were totally capable of doing economically irrational things during the height of the depression. They would throw things away needing only simple repairs.

How it all began…

At the time my trash picking started I was in 7th grade and I was the only student living far enough away from school that I couldn’t make it home for lunch, and back, in the allotted hour. I was a brown bagger.

On an early beautiful spring day I was walking leisurely to school and there in front of me was a beautiful floor lamp. I realized that if I waited until school let out the lamp would have been long deposited in a landfill (we call them junk yards back then.) I picked it up and started walking toward school. About two blocks from school was an empty wooded lot. I put my lamp in the lot and camouflaged it with a few branches and continued to school. I agonized all day worrying that someone would abscond with my lamp.

After school, there is was. I took it home and showed my father and he determined that the lamp had a switch that was not functioning, we went to a local hardware store and purchased a new one. (Home Depots didn’t appear for many decades into the future.) Lamps similar to my trash pick find were selling for about five dollars of 1940s money.

A new switch cost about 20 cents. Although my knowledge of the consequence of the depression was very limited I still found it strange that people would throw away a five dollar lamp because it needed a 20 cent switch. The lamp, with a new shade, occupied a place of honor in the LeJeune household for years to come. My mother, God rest her soul, was very excited about anything I did not requiring a trip to see the principal of my school.

After the experience with the lamp, I started leaving for school about a half hour earlier that I usually did on trash day. One day someone threw away a pair of roller skates (the type you attached to your shoes and tightened with a key.) I fashioned a wagon with a milk box and the skates. I was now ready for the big time of trash collecting. I made a camouflaged den in the lot close to school and was in the trash picking business.

Turning Trash into an Art Form…

Even I was amazed at the quality and variety of things thrown away despite the economic conditions . When a discarded item contained gears I was in Trash-Land heaven. If a discarded item contained a motor, functioning or not, I was in paradise. Thrown away items with gears were especially prized, I used gears mounted on a piece of plywood to make Christmas presents. My relatives told me how creative I was but my artwork typically wound up on their basements wall.

At Christmas time I loaded some of my artwork into wagon and traversed my neighborhood selling my wall hangings. When people asked how much? I replied, “whatever you think it’s worth.” I made enough money to get nice presents for my mother and father.

Spare Parts…

Growing up my family lived in half of a farmhouse. I had a corner of the basement all to myself. My little den served as workshop, storage area, and a laboratory for perform experiments. My attempt at making artificial diamonds was a barn-burner but an article for the future.

Epilogue…

An event viewed through the key-hole of currency frequently takes on a greater meaning when viewed through the rear-view mirror of realism. As an example, the fact that I lived at a greater distance from school than any other student probably lead me to trash pick. If I walked to school with other students I doubt I would not have trash picked.

I went through a period between jobs, a nice euphemism for being unemployed, and money was tight so I put my trash picking days to good use. On the bulletin boards of local super markets I posted notices, “Small appliances repaired , no fix no pay.” The results were a God-send when satisfied customers recommended me to neighbors and friends.

When times are tough we frequently receive the emotional help to give us the strength to get through these period, if we are alert to them.

Are you a licensed ham who is interested in Dstar or DMR – but without the cost of expensive radios?

Here are three steps you can take to accomplish the task. This applies to the three most popular protocols.

It begins by acquiring a special USB Dongle that contains an analog to digital and digital to analog IC chip reffered to as an AMBE3000. They
sell for about $100 but that’s still only 1/4 the cost of an Icom IC-51HT or DV4HOME V2 SDR.

http://nwdigitalradio.com/product/thumbdv

Because only licensed hams are permitted on each system, registration is required.

For Dstar go to:
https://regist.dstargateway.org/Dstar.do
(Login then click REGISTER, it takes 10+- days).

For DMR registration go to:
https://www.radioid.net/cgi-bin/trbo-database/register.cgi

You can confirm your DStar Registration later at:
http://dstar.info/query.html

For software I recommend the free BlueDV Windows client:
http://software.pa7lim.nl/BlueDV/BETA/Windows/BlueDV-09548-preBETA.zip
(note: expand the BlueDV-09548-preBETA.ZIP and RUN the contained .MSI installer).

and here for the latest changes to build 9548:
http://www.pa7lim.nl/bluedv-windows-changelog/

When you plug in the ThumbDV it should create a new “virtual” serial port. Look under Control Panel, Device Manager, Com & LPT . You must note the new COM port# it creates and use that COM# when setting up the BlueDV setup software. Also remember the ThumbDV™
Dongle works at 460800 baud (older models are at 230400).

Be aware that BlueDV build 9548 is BETA, although the Dstar and DMR operations are very stable, Fusion has yet to be fully implemented, currently limited to receive only.

I quote from David, the author: “Press CTRL+1 to activate C4FM (Fusion) on BlueDV but it currently only works in receive mode. I find BlueDV software to be superior to WinDV.

As always, install any software you download online at your own risk. Every computer configuration is different and not all software will be compatible with all systems.

Youtube Help and setup video for BlueDV:

73 & Happy Digitizing!