NAVAL BASE GUAM , GUAM
Story by Petty Officer 1st Class Torrey Lee
Commander, Task Force 75
Commander, Task Force (CTF) 75 successfully completed communications systems tests using high-frequency (HF) radio waves to broadcast voice and data 6,050 miles from Naval Base Guam to Port Hueneme, California, July 27, 2017.
The assessment tested the capabilities of expeditionary forces to use HF waves to deliver data over the Pacific. HF has become a viable alternative for military forces when more common forms of communication, such as satellites, are unavailable.
“In this particular back-up plan, we tested our ability to talk, and we were able to send text to one of our units that is across the Pacific Ocean,” said Lt. Cmdr. Timothy Carmon, a communications planner temporarily assigned to CTF-75. “The transmissions and receptions are not as fast as IP services, however we were still able to communicate in a timely manner with the distant end.”
Utilizing the assets of CTF-75’s Naval Mobile Construction Battalion (NMCB) 1, the command configured its antennae to broadcast to California. Once a successful voice transmission was received, communication directors at Navy Expeditionary Combat Command Pacific requested that CTF-75 try to send a data file.
“These data files allow us to save time,” said Electronics Technician 2nd Class Anthony Juarez, a communications supervisor assigned to NMCB 1. “We can send general diagrams, fire plans and points of interest. Instead of trying to verbally describe something, they [the recipient] have a graphic or a picture that gives them a better idea of the situation.”
Common communication devices used by the U.S. military incorporate satellites. CTF-75 has been testing HF systems in the case of satellite communication failure. HF is a frequency wave broadcast that is transmitted around the curvature of the Earth. Unlike other forms of frequencies, such as very-high frequencies and ultra-high frequencies, the transmission is not distorted by terrain or physical obstructions.
“We may not always have access to operational equipment or the latest assets, but as communicators we should have a backup plan that is ready to be executed,” said Carmon.
Guam is located in the western region of the Pacific. Having an HF range of 6,000 miles is equivalent to broadcasting from Japan to the U.S., or oppositely, from Japan to the middle of Africa. During this most recent test, CTF-75 was also able to establish communications with Mobile Diving and Salvage Unit 1 in Hawaii.
“We can hop our communications from island to island,” said Juarez. “This test gave us the opportunity to know we can push our system to the absolute max from Guam. There are definitely different systems out there, but our system is really efficient at long-range HF. As new radios are incorporated in the Navy expeditionary community, I have no doubt it will get faster, more reliable and easier to set up.”
CTF-75 is currently testing its communication abilities with subordinate commands which include Seabee units, riverine squadrons, cargo handlers, explosive ordnance disposal technicians, and expeditionary intelligence forces.
“This achievement was an important step in an effort to increase our capabilities to be prepared to execute missions in austere locations around the globe,” said Carmon. “Our expeditionary commanders may never need to communicate over a few thousand kilometers, but if the need arises our communicators will be able to provide the connection for that commander.”
CTF-75 is the primary expeditionary task force responsible for the planning and execution of coastal riverine operations, explosive ordnance disposal, diving engineering and underwater construction in the U.S. 7th fleet area of operations.
Many thanks to SWLing Post contributor, Edward Ganshirt, who writes:
This radio followed me home from a flea market and I am trying to find out what it’s mission was.
I think it is a surveillance radio from the Vietnam era because of it’s low serial number #7 R-902 (XE-2)/PRD.
I can’t seem to find anything on it. It tunes from 96 to 404 MHz FM AM CW is battery powered and is totally waterproof (this would be the radio to take white water rafting) .
I would like a schematic or manual for it.
Does anyone in SWL world know anything about it?
Wow! I’m afraid I would have taken that heavy metal home with me too, Edward! And it’s waterproof? What a bonus! 🙂 Actually, I imagine since it’s waterproof, the internals are likely well-preserved.
Post readers: If you can shed some light on this model R-902, please comment. If you have a service manual or schematic, I’m sure Ed would appreciate a link/copy!
If you like military radios as much as I do, you’ll love this video of Andy’s (GW0JXM) R1155 WWII era military HF receiver:
Hat tip to my good friend, Mike, for sending this video!
This past weekend was the Ten-Tec Hamfest, which is held each year at the Ten-Tec factory in Sevierville, Tennessee, USA. I’m particularly fortunate in that I live within a few hour’s drive of the factory, so I make it a point to attend the Hamfest each year.
Hamfests, for those of you not familiar with them, are basically flea markets or swap-meets for amateur radio operators and radio enthusiasts of all stripes. It’s a place to reunite with hobbyist friends and to trade, sell, or purchase new or used radio equipment. The Ten-Tec Hamfest is free, draws a sizable crowd, and what’s more, attendees get the opportunity to try out Ten-Tec radio equipment and tour the factory where their products are made. The Hamfest also coincides with the annual SEDCO DXer/Contester Conference, which is held in the same town, and begins just as the Hamfest winds down.
This year, I had not intended to buy anything. Still, I’m pleased to admit I bought only one item…
My purchase: an LS-166/U loudspeaker. This small speaker has been used extensively in military operations around the world. It’s built like a tank, was perhaps mounted in some, but used primarily used in Jeeps, trucks, and on portable radio packs. The case is made of metal and extremely durable. The two watt speaker has a permanent magnet. It is also fungus, gunblast, and immersion resistant: if you drop this speaker, you don’t need to worry about damaging it–rather, you may need to worry about the floor (or your foot).
The really cool thing about this speaker is that it contains an audio transformer that–via a switch on the side–will allow you to chose between a 600 ohm primary and 8 ohm secondary impedance. The speaker sounds crystal clear, even though mine has obviously received extensive usage. That’s the great thing about military gear–it was designed for functionality, often over-engineered, and certainly built to last!
The LS-166/U is not for listening to music–it was designed primarily for radios that require a high impedance load, and for voice audio clarity. If you’re receiving orders over the radio from your commander, the LS-166/U will punch through the noise from your vehicle and surroundings. It sounds “tinny” if used to listen to shortwave broadcasters, but is actually quite effective when used to listen to amateur radio transmissions and morse code. The 300 Hz to 7 kHz frequency response is ideal for this type of application.
The first rig I hooked up the LS-166/U to was my Hammarlund SP-600, which has a 600 ohm output. Though I know I can hook up a larger, more responsive speaker for better fidelity, there is something rewarding about hearing a speaker that has seen so much service being used once again, and still playing as if new.
As you can see from the photo below, mine lacks the knob on the side of the case. I’ll be looking for one of these at the next Hamfest–or may just order one from Fair Radio.
If you happen to locate the LS-166/U loudspeaker at your local Hamfest, grab one! There are a lot of them floating around and they’re usually quite affordable–typically between $10-20 US (more if mint). I was lucky to pick mine up for $4. Not only is it an affordable piece of military radio history, but I think it would make an excellent external speaker for amateur radio use during outdoor events like Field Day. Indeed, I think this speaker will weather any radio challenge!
So, what else did I see at the Ten-Tec Hamfest this year? Quite a few classic receivers. Though I didn’t take many photos, I did snap a few gems…