Take a step back in time to November 26, 1928, and take a look at what was then described as the biggest and costliest Coast Guard vessel of its era. The photograph shows the state of the art radio room aboard the U.S. Coast Guard Cutter Chelan. At the time this photo was taken, she was the newest cutter in the service, proudly anchored at the Navy Yard in Washington D.C.

Coast Guard Cutter Chelan

Constructed at a staggering cost of approximately $1,000,000 (1928 Dollars), the Chelan proved her incredible value right out of the gate. On her maiden trip, she picked up a desperate SOS signal and successfully towed a disabled schooner 1,500 miles to safety. This remarkable feat stood as a record tow for the service.

Chelan was laid down by Bethlehem Shipbuilding Corporation at Quincy, Massachusetts, on 14 November 1927 and launched on 19 May 1928. She was commissioned into U.S. Coast Guard service as USCGC Chelan on 5 November 1928.

Turbo-electric cutter, Lake-class (250-footers), built by Bethlehem Shipbuilding Corporation, Quincy, MA, at cost of $900,000 (hull & machinery), launched 19 May 1928, commissioned 5 September 1928, 2,075 tons displacement, 250ft long x 42ft beam x 12ft 11in draft, 17.5kts, armed with 1-5in/1-3in/2-6pdr (1929), 97 crew (1940).

The USCGC Chelan (WPG-45) was a 250-foot Lake-class cutter belonging to the United States Coast Guard, launched in 1928. Best known for its extensive operations in Alaska and a dramatic 1937 North Atlantic rescue, the ship was transferred to Great Britain during World War II.

Sitting at the operator station is Ensign Leslie B. Tollaksen. Tollaksen would go on to have a highly decorated military career, eventually serving as a Lieutenant Commander in World War II where he commanded a naval frigate, the USS Moberly, that helped sink a German submarine in the final days of the Atlantic naval war.

We see Tollacksen in the photo above as a fresh ensign aboard USCGC Chelan. From a genealogy page:

Tollaksen “attended the University of Washington for two years before going and graduating from the US Coast Guard Academy in New London, Connecticut. He graduated from The USCG Academy in the Class of 1927, a year early to man the ships chasing down rum runners.

As a young Lieutenant, he was assigned to the US Coast Guard HQ in Washington, DC. He helped establish “Radio Washington” the telegraph station on Telegraph Road in Washington, DC, and also served as Aid to the Secretary of the Treasury, Henry Morgenthau, Jr. (At that time, his sister worked in the typing pool for President Franklin D. Roosevelt’s White House).

Leslie Bliss Tollaksen (1903 – 1973), Also nown as,”Tolley”
Birthdate: April 13, 1903, Port Townsend, Jefferson County, Washington, United States. Death:1973 (69-70), Fort Lauderdale, Broward, Florida, United States

Leslie, about 1937 was the first US Coast Guard Officer selected for Post Graduate School at MIT.

Leslie, during WWII, and in command of the USS Moberly, sank the LAST German U-Boat U-853. U-8533 was a Type IXC/40 U-Boat, and lays on the bottom off Block Island…”

For history and technology buffs, the equipment in this radio room is absolutely fascinating. In 1928, maritime communication was undergoing a major technological revolution. Global maritime operations were beginning to phase out the older, notoriously noisy spark gap transmitters. Instead, the Chelan was outfitted with modern continuous wave vacuum tube technology. This room housed three powerful transmitters and three highly sensitive receiving sets.

If you look closely at the right side of the image, you can see the large glass vacuum tubes safely housed behind protective metal mesh doors. These power tubes allowed operators to transmit signals on specific, sharply tuned frequencies, reaching much further out to sea without causing interference for other ships. The tall black panels are also loaded with large rheostat dials for tuning, as well as precise ammeters and voltmeters to monitor the high voltages running through the system.

Meanwhile, Ensign Tollaksen has his hand positioned near a traditional straight telegraph key to send out Morse code. The receiver units he operated likely utilized regenerative or early superheterodyne circuits, giving operators the incredible sensitivity needed to hear faint SOS calls through heavy atmospheric static. It was exactly this kind of cutting edge machinery that allowed the crew to hear the distress call that led to their record breaking rescue!

USCGC Chelan was a Lake-class cutter belonging to the United States Coast Guard launched on 19 May 1928 and commissioned on 5 September 1928. After 13 years of service to the Coast Guard, she was transferred to the Royal Navy as part of the Lend-Lease Act, and named HMS Lulworth (Y60). During the war Lulworth served in a convoy Escort Group for Western Approaches Command. She returned to the U.S. Coast Guard after World War II.

USCGC Chelan was a Lake-class cutter belonging to the United States Coast Guard launched on 19 May 1928 and commissioned on 5 September 1928. After 13 years of service to the Coast Guard, she was transferred to the Royal Navy as part of the Lend-Lease Act, and named HMS Lulworth (Y60). During the war Lulworth served in a convoy Escort Group for Western Approaches Command. She returned to the U.S. Coast Guard after World War II.

Read more about this vessel: https://en.wikipedia.org/wiki/USCGC_Chelan.

I started in the ham radio and shortwave listening hobby in 1972. By 1975, this was my first real receiver. It heard very well, and ignited my lifelong passion for radio.

The R-366/TRR-5 military receiver.

This old radio, the R-366/TRR-5, which is clearly identified on the faceplate in this picture of the military rig, had great ears. It was what I used to hone my Morse code copying skills and to get the hang of how amateur radio operators conducted communications with each other, with CW, AM, or SSB. I hope someday to own one once again.

The R-366

The R-366/TRR-5 is a significant piece of military history manufactured for the Navy Department Bureau of Ships by the Espey Manufacturing Company. Built during an era when the United States Navy required absolute reliability for ship to shore and ship to ship communications, the unit is a testament to the rugged industrial design of the mid-twentieth century. Often referred to as part of the TRR-5 receiving set, this equipment frequently incorporated high quality components and precision engineering including the gold standard Collins Radio Company designs of that period. These internal components were vital in providing the remarkable stability and selectivity needed to pull weak signals out of the dense electronic noise environment found on a crowded naval vessel. It did have heterodyne squeals on a select few frequencies, which any old tube receiver was prone to have, but those did not detract from the excellent capability of the radio.

The Service

For the sailors and radio operators serving aboard ships in the 1950s and 1960s these receivers were far more than just tools for duty. In the often cramped and isolated conditions of life at sea these radios served as a critical psychological anchor. Access to the bands meant hearing the familiar sounds of home or tuning into MARS stations where amateur radio operators facilitated phone patches that reconnected sailors with their families. This bridge to the outside world was essential for maintaining morale and supporting the mental health of military personnel who were otherwise cut off from the rhythms of civilian life for months at a time. Sitting in the radio shack and slowly tuning that large central dial while listening to the crackle of the ionosphere was a meditative escape from the constant hum of shipboard operations. Many ships would pipe ball games and news shows, or music programs, over the ships intercomms, providing health and morale to the personnel.

Operating the Radio

The tactile experience of operating this specific receiver remains vivid in my memory. The layout with its distinct knobs for selectivity phasing and BFO control was designed for the hands of a professional radio operator who needed to manipulate the signal in real time. It required a disciplined ear and a steady hand to copy Morse code through heavy atmospheric conditions but that struggle made every successful reception feel deeply rewarding. It taught me the patience and technical appreciation that have defined my amateur radio hobby for decades. Owning and using a piece of history like this represented a connection to the generations of operators who stood the watch before me.

Traveling the World…

With this historic military receiver, I discovered an entire world as a child in the mid 1970s. I spent countless nights in the quiet darkness of my room with only the warm orange and yellow glow from the vacuum tubes leaking out of the back and top grills and slots of the radio enclosure, as those hot tubes cast soft light on the ceiling and walls. That radio allowed me to travel the globe from my listening position often sitting cross-legged on the floor in front of this big rig. Those late night listening sessions, when I should have been sleeping, ignited a lifelong passion for understanding the vast and interconnected world of shortwave radio as well as medium-wave DXing. I heard International Shortwave Broadcast stations as well as AM broadcast stations from Europe, Asia, the South Pacific, the Atlantic regions, South America, Central America, and North America–all over the world! I listened to amateur radio operators on Morse code, SSB, and AM modes. Ships at sea, aircraft doing transoceanic flights, fishing vessels comms where fishing captains would chat with other boat captains, and even military communications were all at my fingertips on the dial of the radio as I listened to these exotic places by headphones. I even picked up a station from Peru, South America late one night, on the mediumwave broadcast band. That is how great that receiver could hear. Of course, I had a very excellent outdoor dipole antenna that was cut for 160 meters.

What Receiver Was Your First?

What was your first major receiver? Was it just a receiver, or was it a transceiver? When was that? What did you hear that captured your imagination? Do you still have that radio?
I hope to someday have this R-366/TRR-5, once again.

~ Happy DX!
NW7US

Tektronix 475 - The Beats Keep Coming

How to test?

The scope's fastest native setting is 10 ns/div (labeled as .01µs)

A single cycle of this signal (6.83 ns) will occupy roughly 0.68 divisions on the CRT, so less than one division, which may make it difficult to assess.  But if we engage the X10 Magnifier Switch we get an effective time division of 1 ns/div.  With the magnifier on, one full wave cycle will now stretch across 6.83 divisions (the little squares), creating a waveform that's relatively easy to measure.

I keyed the HT into a dummy load at its lowest power setting next to the oscilloscopes' probe and saw...

Note the time division at 0.1µs and the X10 magnification is pressed

 

I'd venture to say they don't make'em like they used to

Conclusions

In the classic educational film titled “Electronics at Work,” produced by Westinghouse in 1943, viewers are introduced to the fascinating world of vacuum tubes. This film highlights the crucial role these devices played in both military and commercial sectors, including radio telecommunications, radar, and various industrial applications. The narrative suggests that vacuum tubes provided the United States with a significant advantage during World War II, particularly in enhancing communication and technology.

The Continuing Relevance of Vacuum Tubes

Despite advances in technology, vacuum tubes remain in use today for several applications, including:

– Transmitting radios
– Medical devices
– Audio amplification systems
– High-frequency applications

Understanding Vacuum Tubes

The film outlines the six basic functions of electronic tubes and illustrates how each type is employed in different industrial and military contexts.

[embedyt] https://www.youtube.com/watch?v=ZJ6rN7WEjbc[/embedyt]

Structure of a Vacuum Tube

A vacuum tube typically consists of two or more electrodes housed within a vacuum inside an airtight enclosure. Key features include:

– Electrode Types: Most vacuum tubes have glass envelopes, although some utilize ceramic or metal casings with insulating bases.

– Leads and Sockets: The electrodes connect to leads that pass through the envelope via an airtight seal. These leads often take the form of pins, allowing for easy replacement in a tube socket, as tubes were a common point of failure in electronic devices.

– Capacitive Design: Some tubes feature a top cap on the electrode to minimize interelectrode capacitance, enhancing high-frequency performance and maintaining safety by separating high voltages.

The Evolution of Vacuum Tubes

The earliest vacuum tubes emerged from incandescent light bulbs, which contained a heated filament sealed in an evacuated glass envelope. When heated, the filament releases electrons into the vacuum through a process known as thermionic emission.

– Electrode Functionality: A second electrode, known as the anode or plate, attracts these electrons if it holds a more positive voltage. This mechanism results in a flow of electrons from the filament (cathode) to the plate, creating an electric field due to the potential difference between them.

– Diode Function: A vacuum tube with two electrodes is termed a diode, which functions as a rectifier. Diodes allow current to flow in only one direction, converting alternating current (AC) into pulsating direct current (DC). This technology is widely used in DC power supplies and in demodulating amplitude-modulated (AM) radio signals.

Film Availability and Production Details

This film is available in the public domain under Creative Commons, and it can be accessed through the Library of Congress Prelinger Archives. The film has been edited and converted to HD quality for better viewing. Introductory and closing music is provided by Nero 10, with commercial use rights granted.

This film not only serves as an educational tool but also highlights the enduring legacy of vacuum tube technology in the realm of electronics, illustrating its significant contributions to both past and present technological advancements.

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Decibels are commonly used in electronic communications to describe and compare signal levels. I’ve often heard that one dB is considered to be the smallest change that a typical person can detect by ear. I recently came across this website audiocheck.net that is set up to generate different audio tones and to do a blind test of how small of a change you can detect.

I started with testing for 6-dB and 3-dB changes. Easy Peasy. Then I tried the 1-dB test. I could detect the change in level fairly consistently but I did have to concentrate. Continuing on to the 0.5-dB change, I had a very high failure rate. It was very difficult to detect that small of a change. So I have to conclude that 1 dB is about the limit for a change I can hear.

How about you? Take the test on the website and let us know how you did.

There are many other audio tests to explore on that site, including the highest frequency you can hear, the minimum pitch change you can hear, etc. Check it out: www.audiocheck.net

73 Bob K0NR

The post Can You Hear a 1-dB Change? appeared first on The KØNR Radio Site.

Recently, Retail Ecommerce Ventures (REV) announced its purchase of certain iconic RadioShack brands and related assets. Many radio amateurs and electronics hobbyists would like to see something happen in the way of a new, improved RadioShack, whether online or via brick-and-mortar stores. RadioShack is still a strong brand but it takes more than a brand to drive success in business. Count me as a bit skeptical that anything significant will happen with this move but I would be happy to be wrong about that.

A quick look at the RadioShack.com web site reveals some cross-selling on the top of the home page to Linens+Things, Pier 1, Dressbarn, Farmerscart, The Franklin Mint and Modell’s. In what marketing universe does that make sense?

RadioShack Brands

Not too long ago, I got to looking at the list of old RadioShack brand names. I thought I was a tech-savvy RadioShack dude but quickly found out they had a boatload of brand names that I never heard of. (One could argue that RadioShack completely messed up its branding strategy with so many diverse product line brands.)

Here’s what I found:

AntennaCraft (outdoor antennas and amplifiers)
Auvio (audio/video cables, LCD TV’s, headphones, premium surge protectors and speakers)
Enercell (batteries and power)
Gigaware (computer, GPS and iPod accessories, mp3 players and accessories, as well as digital cameras, digital camera accessories)
PointMobl (Wireless Phone Accessories)
Accurian (audio and video equipment and accessories)
MyMusix (MP3 players; later marketed under the Gigaware brand)
Kronus (tools)
Optimus (formerly audio and PA/DJ equipment; later used for digital camera accessories)
Presidian (audio and video equipment, telephones, flashlights,calculators, and 2-way radios)
VoiceStar (wireless phone accessories)
Archer (wiring and antennas)
Duofone (telephones & accessories)
Micronta (scientific and educational equipment)
Realistic (used broadly for radio and audio equipment)

Source: http://www.lb7.uscourts.gov/documents/14-14713.pdf

And if you want to go deeper, here is a history page on the RadioShack company.

Maybe they will bring back the Battery-A-Month Club.

73 Bob K0NR

The post RadioShack Brands appeared first on The KØNR Radio Site.

The light-bulb dummy load has been used with HF transceivers from way back in the old days (and sometimes more recently). Also, the Lightbulb QSO Party promoted the use of light bulbs as antennas.

I wanted to find out if I could do the same thing with a 5W handheld transceiver, so I scavenged a bulb from an old string of Christmas tree lights and hooked it up to my Yaesu FT-60. This video shows what happened next.

After I made the video, I checked the specs on the FT-60 and found that the transmit power settings are: 5.0 W (High) / 2.0 W (Middle) / 0.5 W (Low). In the video, I said the middle setting was one half watt, which is incorrect.

I checked the SWR on the light bulb and found it to be 2.7. I was not worried about damaging the handheld radio because they are designed to work into crummy antennas such as the standard rubber duck.

I hope you enjoyed this fun experiment. Sorry about the amateurish video quality…I just shot it with my iPhone and did some simple editing.

73 Bob K0NR

The post HT and Light Bulb Load appeared first on The KØNR Radio Site.