Yagis, DMR Portables and Underwater Communications

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

The Yagi-Uda Mystery: The Remarkable Backstory of this Ubiquitous Antenna
By Richard Fisher KI6SN

Shintaro Uda and Hidetsugu Yagi were mirror images of the antenna they created in 1926—known around the world today simply as the Yagi—an array invented by Uda in collaboration with Yagi. Ninety-three years later, this design is still widely in use for both amateur and commercial installations on the HF, VHF/UHF bands and beyond. It is the antenna so often seen atop amateur radio towers, at military installations and many municipal and commercial buildings. Yet Shintaro Uda seems to have faded from the picture of the origins of this antenna. Richard tells us about two stories of intrigue and historical significance behind the Yagi.

TSM Reviews: Yaesu FT3DR and Radioditty GD-73A
By Cory GB Sickles WA3UVV

The Yaesu FT3DR and the Radioddity GD-73A are two very different digital voice (DV) portables, with widely divergent feature sets. Each needs to be considered for its merits and the applications you have in mind. The Yaesu FT3DR is the latest of a series of DV hand-held portables with the features you’d expect from a full-featured HT. The Radioddity GD-73A is a UHF-only, DMR/analog portable with minimal features: There is no provision for an external antenna and the internal one protrudes under plastic, much in the same way as a 0.5-watt blister-pack FRS (Family Radio Service) transceiver is packaged. Cory goes deep into the details and tells us there’s more to each than may be at first apparent.

The USS Thresher on Eternal Patrol
By Scott A. Caldwell

The USS Thresher(SSN 593) was an icon of the United States Navy and was often used in recruitment posters. She was regarded as the most technologically advanced submarine in active service, designed to hunt and engage Soviet submarines that patrolled the deep North Atlantic Ocean. Her loss on April 10, 1963 shocked the entire nation and the subsequent inquiry raised more questions than answers, in light of the confusing radio transmission with the submarine escort vessel USS Skylark (ASR 20). Underwater communications were subjected to temperature and density fluctuations that often deflected and distorted the amplitude of the sound waves. Scott looks at the difficulties of undersea communications while telling the story of this disaster.

The Care and Feeding of Electronic Equipment: Part 2
By Robert Gulley K4KPM

Electronic equipment for our radio hobby requires periodic checks for proper operation, as well as occasionally performing preventive maintenance or repair as needed. This includes radios, power supplies/connections, computer hardware, antenna systems, and a host of other potential troublemakers. In this second article Robert discuss troubleshooting tips, electrical and antenna system maintenance, computer hardware/software updates, and other preventative measures to help keep things running as smoothly as possible.

Scanning America
By Dan Veeneman
Scanning Michigan

Federal Wavelengths
By Chris Parris
Las Vegas Mysteries and Frequencies

Milcom
By Larry Van Horn N5FPW
A New Way to Monitor the Military on January 1, 2020

Utility Planet
By Hugh Stegman
Cycle 25: Coming to an Ionosphere Near You

Shortwave Utility Logs
By Mike Chace-Ortiz and Hugh Stegman

VHF and Above
By Joe Lynch N6CL
The ‘Ah-Ha’ Behind Some Types of Aurorae

Digitally Speaking
By Cory GB Sickles WA3UVV
Another Look at D-Star

Radio 101
By Ken Reitz KS4ZR
The Trouble with Alexa

Radio Propagation
By Tomas Hood NW7US
Sunspot Cycle 24 Solar Minimum is Coming!

The World of Shortwave Listening
By Rob Wagner VK3BVW
Whatever Happened to the 11-Meter Band?

The Shortwave Listener
By Fred Waterer
German via Shortwave Plus BBC Highlights

Amateur Radio Astronomy
By Stan Nelson KB5VL
The Next Generation Very Large Array: ngVLAA

Adventures in Radio Restoration
By Rich Post KB8TAD
The Rolls-Royce of Radios: National HRO Part 2

Antenna Connections
By Dan Farber AC0LW
The End-Fed Antenna

The Spectrum Monitor is available in PDF format which can be read on any desktop, laptop, iPad®, Kindle® Fire, or other device capable of opening a PDF file. Annual subscription is $24. Individual monthly issues are available for $3 each.

Ken Reitz, KS4ZR, is publisher and managing editor of The Spectrum Monitor. Contact him at [email protected].

One Response to “Yagis, DMR Portables and Underwater Communications”

  • David, KJ4CMY:

    I am a charter subscriber of The Spectrum Monitor. It is an excellent magazine, well worth the price.

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