HF broadcasting station maintenance

This video shows some of the maintenance required for an HF (AKA Shortwave) broadcast station. It starts with transmission line tensioning, some shots of a curtain array then goes on to show the inside of a transmitter building. Transmitters shown are Harris HF-100 (a 1980’s model tube type PDM design) and Continental 418, but I didn’t see the letter number. They are likely tube-modulated units.

These are from the international service of Australia Broadcasting Corporation (ABC), or Radio Australia International.

Goodbye, RCI 1945-2012

RCI logo
RCI logo

In yet another example of government-sponsored international broadcasting ending, Radio Canada International calls it quits after 67 years.  Effective June 24, all broadcasts from RCI’s Sackville shortwave relay site will cease.  All satellite distribution will end and seventy-five percent of the RCI workforce will be laid off.  This means the end of almost all RCI original content.  The good news, according to the press release, is that RCI will continue on webcasting.

This is due to budget cuts to the CBC, which administers RCI.  The Canadian Parliament cut the RCI budget from $12.3 million CAD to $2.3 million CAD for 2012.  This cut in expenditures is saving each Canadian resident approximately $0.35 CAD per year.

Thus, this weekend is the last chance to hear RCI or CBCNord Quebec on any HF frequency.

I listened to RCI for many years, until they drastically reduced their English language shortwave broadcasts to North America in 2006.  Simply put, HF broadcasters are folding up shop and moving toward web-based distribution networks.  Those HF transmitters are expensive and they do not maintain themselves.

One drawback of this scheme is government censorship.  It is very easy to the government to block access to sites via internet firewalls.  It is very difficult to completely jam a radio station.

And perhaps those considerations are not important.

RCI transmitter site, Sackville, NB
RCI transmitter site, Sackville, NB, courtesy of Wikipedia

I wonder what will happen to their transmitters after sign-off?  According to the wikipedia article there are nine HF transmitters in use, with power levels ranging from 100-300 KW.  They are likely to be hauled away and scrapped, the building torn down.

CHU: Time nor tide waits for no man

CHU is an HF time signal station operated by the National Research Council of Canada. It operates 24/7 and announces the hour and minute each minute of every day on frequencies 3,330, 7,850, and 14,670 KHz. This is the Canadian counterpart to WWV and WWVH.  In the strictest sense of the term, it is a broadcasting station, although many would also classify it as an HF utility station as well.  Many countries had HF time signal radio stations at one time, but there are fewer now.  Back in the day before GPS, these time signals were critically important to anyone needing coordinated event timing.  We used the carrier frequency from WWVH as our frequency standard for test equipment.  WWV and WWVH also transmitted a very accurate 1 kHz tone for the same purpose.   According to the CHU website:

Normally CHU’s emission times are accurate to 10-4 s, with carrier frequency accuracy of 5×10-12, compared to NRC’s primary clocks, which are usually within 10 microseconds and 1×10-13 compared to UTC.

Additionally, every minute between 31 and 39 seconds, CHU broadcasts FSK time code with a Bell 103 standard (2225 Hz mark, 2025 Hz space) at 300 bits/second (IRIG time code).  This could be used as a backup for GPS time clocks on automation systems if GPS were to fail for some reason. One would have to write a little software program to decode the hex output and reset the computer clock once per minute accordingly.  That should not be too hard.  LINUX information and software can be found here.  More on CHU time code here.

CHU Ottawa, Ontario, Canada
CHU Ottawa, Ontario, Canada

In my location 3,330 KHz is audible 24/7.  That signal is transmitted with a carrier power of 3 KW into a non-directional vertical dipole antenna as is 14,670 KHz.  The 7,850 KHz signal is transmitted with a carrier power of 10 KW into the same type of antenna.

Canadian Time Signal station CHU, aerial view
Canadian Time Signal station CHU, aerial view

There is some discussion of adding an additional time station transmitter in western Canada and of changing the modulation from AM to DRM or at least adding some type of DRM service.

Coast Guard Radio Guam/NRV, part II

I am fascinated by history, especially when it involves places or events that I am connected to.  This is the history of US Coast Guard radio station Guam.

In the closing days of WWII, the US Coast Guard was busily installing and manning LORAN A stations around the world.  In the Pacific, often before the smoke of battle dissipated, Navy and Coast Guard construction detachments quickly built LORAN stations to aide the war effort.  After the war, some of these stations were moved or consolidated to better locations.

More about LORAN history can be read at LORAN History website.

Along with the LORAN stations, which were often located on remote (read desolate) islands, a large support system evolved.  This included Section offices, which oversaw about 8-10 individual LORAN stations, LORAN monitoring stations, Coast Guard air stations or air detachments, which flew in supplies and personnel, and communications facilities.

LORAN A, the first version of LORAN worked on 1750 KHz, 1850 KHz, 1900 kHz, and 1950 KHz just above the AM broadcast band with moderate to low power levels.  The signals were timed precisely with Caesium clocks and against each other. Charts were issued with TD lines, which were basically timing lines based on the distance from a certain transmitter.  A LORAN receiver on board a ship or aircraft would receive two or more transmitting stations, then the navigator would be able to compare the TD lines on the LORAN chart to determine where they were located.  This worked because radio waves travel at the speed of light, which is a constant.

Since LORAN A worked on Medium Frequency (MF), the usable distances were not great, especially in the tropics, where MF does not carry far.  Thus there were several LORAN A chains throughout the Western Pacific.  There were also several Section offices, one in Japan (Far East Section or FESEC), one in the Philippines (Philippines Section or PHILSEC), and one on Guam (Marianas Section or MARSEC).  Each of these section offices had a radio station attached, at FESEC it was NRT, at PHILSEC it was NRX and at MARSEC it was NRV.

US Coast Guard Guam Depot, circa 1960
US Coast Guard Guam Depot, circa 1960

Coast Guard Guam Radio Station/NRV was an adjunct of the MARSEC command, occupying a small corner of an “Elephant” Quonset Hut on Cabras Island.  The Elephant Quonset huts were the largest size half-round corrugated steel structures that were quickly erected during the War.  They had two floors and were not normally air-conditioned, which is a significant detail on Guam.  Several of these structures, located on various naval bases, survived numerous typhoons and the harsh tropical environment up until the year 2000 or so.  In this picture, there are a couple of HF vertical whip antennas evident.  These would have had antenna tuners and been used in the 5-25 MHz range.

Most people think of the Pacific War and think of jungle and dense overgrowth.  In the south pacific, that was often the case, however in the central pacific, often it was a dusty hot coral aggregate surface once the Seabees finished their work.

NRV consisted of four radiomen standing six-hour watches.  Their duties included communicating with civilian ships entering the port of Guam and communicating with various Coast Guard units in the western Pacific, including LORAN A stations on Ulithi, Yap, Saipan, Marcus Island, Iwo Jima, Angaur Island (Palau), as well as air guard for any aircraft in flight and ship guard for any cutters underway in the MARSEC operational area.  Almost all of the message traffic was sent by Morse code on High Frequency (HF). The radio room NRV occupied was noted to be about the same size as a radio room on a Medium Endurance cutter.

Aerial view of building 150 and antenna fields
Aerial view of building 150 and antenna fields

This operational configuration continued until about 1966, when Cabras Island was transferred from the Navy to the newly established Government of Guam, for use as a commercial port.  At that time, MARSEC moved to a new building next to Victor Warf, onboard Naval Station Apra Harbor and the Radio Station (RADSTA) Guam moved to Building 150, at the Navy Communication Station/NPN, Finegayan (Dededo).

Building 150 was the primary operations center/receiver site for the Navy. It was located in the middle of a large antenna field, with long rhombic antennas pointed at various locations throughout the Pacific. This location was chosen by the Navy during WWII for its excellent ground conductivity.  The closest geographical reference for Building 150 is Pugua Point, located on a high plateau overlooking the Philippine Sea, to the west.  Prior to WWII, this area was primarily ranches and farms because of its good soil, not found in many other places on Guam.

RADSTA Guam was on the first floor, in an open room without partitions between operating positions.  It was at this time that NRV took over primary responsibility for monitoring 500 KHz distress and calling frequency from NPN. LORAN A was being phased out for LORAN C, which required fewer transmitting sites.  Facilities in the Philippines, Marianas and Japan LORAN A chains were combined into one Western Pacific LORAN C chain.  The final LORAN A station was turned off in 1978.

USCGC Basswood, WLB-388 courtesy of Coast Guard Historians office
USCGC Basswood, WLB-388 courtesy of Coast Guard Historians office

This reduced NRV’s workload considerably, as radio was replaced by landline circuits at all but the two most remote LORAN C stations; Iwo Jima/NRT3 and Marcus Island/NRV6. In addition to the LORAN stations, the CGC BASSWOOD/NODG (arrived 1968), CGC CAPE GEORGE/NRDT (arrived 1981) and CG Air Station/Air Detachment Guam (1950-1972) were all supported.

The transmitters were remotely located at the Navy Radio Transmitter Facility (NRTF) Barrigada, approximately 12 miles to the southwest.  Keying was sent via buried cable to building 112 where a microwave link completed the circuit to Barrigada.  Transmitters were generally AN/FRT-70’s which were 1 Kilowatt HF units, however, other transmitters, power levels, and antennas were available on request.

It was at this time, NRV began functioning more like a commercial coastal radio station, maintaining watch and answering calls on HF CW calling channels, relaying commercial messages to shipping interests on Guam and beyond.

The Navy provided all supporting functions including dining, living quarters, medical, dental, etc.  They also owned all of the equipment such as teletypes, some of the receivers, antennas, landline circuits, etc.

The Navy moved the majority of its operations to Building 112, which we referred to as “Tech Control.”

In 1980, the designation was changed from “Radio Station” to “Communications Station.”  NRV moved upstairs to the second floor of building 150.  This was the final location and configuration for NRV.  It was at this time the NRV took over keying the HF CW GCMP broadcasts from the Navy.  The GCMP broadcasts were the last surviving Morse code fleet broadcast and used separate frequencies in the 8/12/16 and 22 MHz bands from NRV’s HF CW working position.  SITOR service was also added about this time.  During this period, there were four watch sections consisting of five to six watch standers each.  The CO, XO, and OPS boss were day workers as were new arrivals.  Thus the total station complement was about 28 people, all radiomen, except the CO, who was a CWO2.   NAVTEX service (ID V) was added in 1990 on 518 KHz.

When I reported aboard in April 1988, I received the following description of the station from the command welcome aboard package:


12 January 1987

Communications Station Guam/NRV is located in building 150 onboard U.S. Naval Communications Area Master Station (NAVCAMS) Western Pacific.  Communications Station Guam is the major relay station for all Coast Guard units located in the Western Pacific region.

Communication Station Guam is a unique unit within the communications community.  It serves the typical needs of it’s geographic area as would any COMMSTA, plus it also functions at various times as a MINI-COMMCEN, a SAR communications relay unit and a commercial coastal station.

To get a better understanding of how COMMSTA Guam functions it is first helpful to get an idea of the physical layout of the station.

After entering the station through a chipher-lock door, and passing through a short corridor, one enters the main communications area.  Here are the majority of the teletype circuits and equipment, patch panels and the five operator positions, of which four are contained in separate cubicles (ed note: rooms) numbered 1 through 4 situated in a clockwise pattern.

POSITION 1 is the primary SAR position at the station.  The operator maintains a 24 hour headphone dedicated watch on the international calling and distress CW (morse code) frequency, 500 KHz.  The operator is required to make log entries of signals intercepted at a minimum of every 5 minutes.  The operator also operates three model 28 teletypes (ed note: replaced by computer terminals in 1989) used to communicate with merchant and USNS vessels via SITOR (Simplex Teletype Over Radio)

POSTION 2 is responsible for maintaining communications over several different circuits.  Here, the operator monitors the Loran-C voice net and frequently utilizes it to coordinate communications primarily with LORSTAS Iwo Jima, Marcus Island, Gesashi, Hokkaido, Yap and FESEC in times of emergencies.  A continuous listening watch is also maintained on the Coast Guard System Coordination Net (SCN).  Although the primary purpose of the SCN is to coordinate communications between COMMSTA’s and Cutters, it is often used as a long range SAR contact frequency by merchant vessels, yachts on the high seas, and the like.  When CGC Cape George, Basswood, or any other cutter operating in our area are underway, the position 2 operator maintains uncovered radioteletype communications with the vessels.   Utilizing ARQ (Automatic Repeat Query) equipment, the operator is responsible of receipt and delivery of all record traffic for LORSTAS Marcus Island and Iwo Jima.  Lastly, COMMSTA Guam maintains an aircraft Air-to-Ground circuit in position 2, when required.

POSITION 3 is considered by our operators as the most challenging and rewarding position at COMMSTA Guam.  The HF CW (AMVER) position.  (AMVER stands for Automated Mutual Vessel Assistance Reporting) Here the operator must listen continuously to nine different channelized frequencies on six different receivers each with it’s own speaker.  Through the “dits” and “dahs”, screechs, howls, and woodpecker sounds on the bands, the operator must try to detect and discern the often weak and barely perceptible signals from ships calling NRV.  Often calls come from ships off the coast of South America to the Indian Ocean and even the North Atlantic.  Only the most skilled CW operators man this position during peak traffic periods.  High speed proficiency in CW is the number one goal of all operators at NRV.

POSITION 4 is the Broadcast Position.  From position 4 is keyed CW transmitters on Guam, in the Philippines (NPO), Australia (NWC) and upon request Diego Garcia.  Transmitting weather, hydrographic reports and record traffic to various allied fleet ships, the “GCMP Broadcast” was acquired from the Navy in 1980.  The position four operator is also responsible for guarding the VHF-FM channel 16 calling and distress frequency used by local fishermen and the boating public.  Additionally, the 2182 KHz international calling and distress frequency is guarded in position four. (ed note: HF, MF and VHF voice weather broadcasts were also sent from this position)

POSITION 5 brings together the combined efforts of the positions 1 through 4.  The CWO, Landline Operator/Supervisor Position.  Here, the processing of all incoming and outgoing messages over the NAVCOMPARS circuit, OV-42 circuit and the K-198 Weather circuit to Hawaii takes place.  Although position five is manned by senior petty officers billeted for the station, a goal of junior operators is to qualify for certification at position five.

The preceding description of the responsibilities of COMMSTA Guam is by no means complete.  Flexibility is the key to successful and timely fulfillment of our mission which constantly changes in its scope and magnitude.

Based on that description and my own memory, I drew out the following floor plan as the station was in 1988-1990.  The operating positions were about 12 x 12 foot rooms, perhaps slightly larger.  The main floor was about 30 x 30 or so, and the CO’s office was twice the size of the XO/OPS boss’s office.  It might not be totally accurate, but it is close:

Communications Station Guam/NRV circa 1989
Communications Station Guam/NRV circa 1989

The positions where the watches were stood were relatively small rooms.  The normal position rotation schedule was 4 hours in each of the positions one, two and three.  This worked to keep the watch operators fresh, as each position had a different skill set.  Position 4 was stood by the same person for the entire 12 hour watch, this was to keep the broadcasts consistent.  It was also the least challenging position unless there were multiple typhoons active in the western Pacific.

The watch supervisor was usually a senior RM2 or RM1 and the chief watch officer was a senior RM1 or RMC.  The Position 5 nomenclature sort of dropped out of usage when I was there, it was generally called the “supervisor or CWO” position.

Watches were 12 hours on/12 hours off for three days.  After a day watch rotation (three days of working from 6:30 am to 6:30 pm), there were two and a half days off then the night rotation started, which was another 12 on/12 off period for three nights (6:30 pm to 6:30 am).  This was followed by four days off.

By 1993, the western Pacific LORAN chain was either turned over to the Government of Japan or decommissioned.  The 500 KHz watch, HF CW service and GCMP broadcasts were all discontinued.  Other functions, such as SCN (Ship Coordination Network), HF voice, and SITOR services were remoted to COMMSTA Honolulu, HI/NMO.  This effectively closed the station down.  By late 1992, all personnel were transferred to other commands.  In 1997 NMO’s operations were in turn remoted to CAMSPAC/NMC.  VHF channel 16 and 2182 KHz are monitored by Sector Guam (the former MARSEC).  In 2008, NRV stopped accepting OBS and AMVER reports via SITOR.  The HF voice and SITOR weather and NTM broadcasts continue as of 2011, keyed from CAMSPAC/NMC.

For general operating conditions in the late 1980’s and early 1990’s, read my recollections on working there.