Guam to California: CTF 75 successfully tests HF communications system

Electronics Technician 2nd Class Anthony Juarez and Electronics Technician 3rd Class Codie Flanagan, assigned to Naval Mobile Construction Battalion (NMCB)1, adjust frequency codes on a GRC-234 high-frequency base station at Naval Base Guam July 27, 2017. (Source: DVIDS)

(Source: Defense Video Imagery Distribution System)

Story by Petty Officer 1st Class Torrey Lee
Commander, Task Force 75
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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.

Read the full article at the DVIDS hub…

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6 thoughts on “Guam to California: CTF 75 successfully tests HF communications system

  1. Ross

    Given the current political situation ie ( Nth Korea and its continuing belligerent threats) setting up an HF comms system in Guam is quite interesting, Nth Korea is a known hacking state and I wonder if finally govts are beginning to realize that good ole HF is not a dead entity and that it not only offers an alternative comms system to satellite and digital microwave VHF UHF etc but may be a vital backstop if things go peareshaped.
    Sadly with SW stations being shut down around the globe and dependency on digital data systems via internet and Sats we may be open to a distinct inability to mass communicate via what has been an extremely reliable and competent way of communications if major hacking or links are broken in the future.
    Just my take Ross.

  2. Jon Hendrickson

    Everything old is new again. HF phone, RTTY and FAX were state of the art wireless technology when I graduated from Radioman “A” school in 1971. If you could connect to cables, it was Autovon (voice) and Autodin (digital messaging). The fleet was just starting to use satellite around that time.

  3. Robert Weingaertner

    Yes, so many HF facilities (broadcasting, maritime, etc) have been demolished in favor of VHF and internet connectivity. No one seems to realize that the internet can be blocked, censored or monitored by the bad guys. Radio links dependent on the internet can be disrupted by natural disasters or “denial of service” hack attacks.

    The military rediscovered HF years ago. Back in 1981, when I was doing some navigation system tests at Lakehurst NAS in NJ, I ran into a couple of guys from Ft. Monmouth who were conducting HF Near Vertical Incidence Skywave (NVIS) experiments as an efficient way to use HF over short ranges that did not afford line of sight paths for VHF. They also developed an efficient mobile HF “shorted loop” antenna for vehicles and helicopters. I was able to get a copy of their report and it made me a NVIS believer.

    HF was also used in Operation Desert Storm partly because there were not enough SATCOM channels to go around.

    HF capability for SWLs and hams in urban and suburban areas is steadily being degraded by antenna restrictions and rising man-made noise levels. HF is a precious resource that should not be wasted.

    73, Bob WB2VUF

  4. Kris, G8AUU

    Reads a little bit like “reinventing-the-wheel”. Would not be surprised if there are not some radio amateurs in the CTF-75 team.

    Liked the bit about HF signals following the curvature of the earth.

    Voice, data on HF all sounds very familiar. Did note that there was no mention of that very basic data transmission format, Morse code..!

    What was missing from the report though was any mention of TX power levels used or antennas. Mil secret?

  5. Ron Ellwood

    I am surprised at all those radio stations who have pulled down their towers and gone over to the Internet only service. They do not seem to be aware that satellites can be hacked or be affected by severe solar radiation etc. It looks like the military are aware and have contingency plans in case this happens.


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