Reprinted with permission of the author, Jeff Herman, KH60. Jeff granted me permission so that his personal maritime radio experiences will not be taken to the grave with him. I’ve added the large descriptive paragraph headers to help maintain reader interest and engagement. Thank you Mr. Herman for allowing me to curate your unique and touching perspective of maritime radio. – Tim Carter, W3ATB
I recommend you watch this video first and much of what Jeff writes below it will make more sense. You’ll also get a feel of what it was like being a marine operator.
The following seven-part series has been recorded for the historical record. We are witnessing a never-to-return era of communications style and format that was so perfect that nothing will ever be its equal. I am very glad that I was able to be a part of it, if only for three years at the US Coast Guard Radio Station Honolulu, call sign NMO.
In July of 1977, as a 3rd Class Radioman Petty Officer for the U.S. Coast Guard, I received orders to report from Coast Guard Group Monterey, CA, to Coast Guard Radio Station Honolulu in Wahiawa, Hawaii. I had graduated from Radioman School a year earlier concluding 5 months of training in code, propagation, radio fundamentals, ITU procedures, and other disciplines. The minimum code speed needed to graduate was 22 words per minute; mine was 25.
Radio Honolulu, NMO, is situated on a huge plot of land owned by the Navy, centered in the pineapple fields of Oahu. In addition to NMO, the Navy and the Marine Corps had their Central Pacific Communications command based there as well.
By the way, NMO has the longest overwater microwave link in the world; Oahu to the island of Kauai for VHF marine band operations. NMO was set up with the following glass-enclosed operating positions: 500 kc CW, HF CW, HF and VHF voice, air-to-ground, RTTY, Fleet Broadcast, landline TTY, and the Chief’s desk. From where the Chief RM sat, he could watch all of the ops to make sure no one fell asleep; pity the poor operator (op) who was caught sleeping while on watch!
Coast Guard Public Interface
The Coast Guard is the only military service that communicates directly with the public. Thus, we had to know when to turn off the military radio jargon, particularily on 2182 kc, the MF international voice calling and distress frequency and channel 16/156.80 Mc, the international VHF voice calling and distress frequencies.
The voice op was kept busy monitoring over a dozen voice channels: 2182 kc, the 4, 6, 8, 12, and 16 Mc high-seas SSB ship-to- shore frequencies, four VHF repeaters for channel 16. NMO had a microwave repeater on Kauai, Oahu, Maui, and the Big Island. There were four repeaters for VHF channel 23, and whatever else the Chief felt should be monitored.
Several times each radio day, the voice op had to make weather (WX) broadcasts, Notice To Mariners, etc.. on all these frequencies. The timing was critical so the clock had to be checked frequently.
High-Frequency Morse Code Ops
The HF CW position required 2 ops using two racks each consisting of: four Collins 651S digital readout receivers scanning the CW calling bands on 4, 6, 8, 12, 16, and 22 megacycles (Mc). In daytime hours, one op would take 8 and 12 Mcs – the other operator would take 16 and 22 Mcs; at night time, one operated 4 and 6 Mcs – the other would have 8 and 12 Mcs.
So, an operator might have 8 Mc scanning in his left ear and 12 Mc scanning in his right since the receivers automatically scanned a preset band of frequencies. For example, the 8 Mc calling band for ships calling shore stations runs from 8360.4 to 8374 kcs.
A ship calling us might have to send our callsign 20 to 30 times (no 3 by 3 format here!) while our receiver scanned. The NMO op would then hear, from the highest to lowest to highest notes possible (within 1 to 2 seconds) of our callsign being sent; he would quickly shut off the scanner, tune in the ship and turn off our CQ tape. When no traffic was being passed, we would keep the transmitters busy sending:
CQ CQ CQ DE NMO NMO NMO QRU QRU IMI OBS AMVER QSS 4 6 8 12 16 22 MHZ AR – (sort of an advertisement for traffic), and the exchange might go some thing like this:
- DE NMO
- NMO DE KNFB OBS 8360 K
- KNFB DE NMO R UP
That meant the ship has a weather observation. (Every 6 hours starting at 0000Z every ship worldwide takes an OBS and passes it, at no charge, to the closest shore station).
This ship wants me to listen for him on 8360 kilocycles (kc); he’ll continue to listen to me on NMO’s fixed transmitter frequency. Notice the signal ‘UP’. This means: `I’m shifting up to that freq’. Any exchange ALWAYS ends with `dit dit’ (and hams thought they invented that!).
Having one ship calling in at a time was rare. During the OBS hour, not one ship would call, but dozens and dozens would be calling. All of this traffic was monitored with both ears and the receivers scanning! The NMO operator would have to line them up numerically:
- KNFB DE NMO UR NR 1
- R 8360 TU
- WSLH UR 2
- R 12561 TKS
- 7XYM UR NR 3
- DE 7XYM 8370 R UP
- JGFD UR 25
- OK UP 8375 TU
Then, the op would copy the WX OBS from each ship one by one.
Get Data Fast
After working that group of 25 ships he’d turn on the CQ tape again and scanners, and dozens more ships would pounce on him. Since WX is time-sensitive, it was a race to `collect’ as many OBS as humanly possible. A lazy op might only get 100 during a 30 to 45 minute period.
Small Room – Big Responsibility
Sitting adjacent to the HF CW position was a smaller room, enclosed on three sides in brick and painted off-white. The fourth side was glass which also included a sliding glass door, affixed with a small sign which simply said ‘MF CW’. This little booth of modest appearance was well out of proportion with respect to the role that MF CW had played in the history of maritime communications.
Inadvertently or by intention, the Chief’s desk was positioned so he had a direct view of the MF CW booth. The Chief’s position had a compliment of Collins receivers, and one was always tuned to 500 kc. More often than not, I’d get a glimpse of the duty Chief listening, with a gleam in his eye, to the evening traffic on 500 Kc.
Giant 24-Hour Clock
Upon entering the MF position, one was struck with the sight of the largest 24 hour clock known to mankind. It had the most unusual red markings on its face. Two red wedges, starting from the center and flaring outward covered, respectively, minutes :15 to :18, and minutes :45 to :48.
These, of course, were a blatant reminder to the operator of the two worldwide silent periods (more one these later). In addition, each of the twelve five-second intervals around the perimeter, had the first four seconds blocks marked in red with the last second left white.
The sequence was: 4 seconds red, 1 second white, 4 seconds red, 1 second white, etc., around the entire circumference. These markings were to aid the 500 kc operator in manually sending the distress auto alarm: key down 4 seconds, key up 1 second, key down 4 seconds, key up 1 second, etc., for one minute. More on the auto alarm later.
Multiple Receivers Capture Signals
One’s attention would next be drawn to two Collins 651S receivers mounted in the operators console. The top receiver was locked on 500.000 kc and the bottom was usually a few hundred cps on either side of 500, say 499.500 kc. This, of course, prevented missing signals with whom our receivers were zero-beated with.
The audio from these two receivers was fed into a 12-track reel-to-reel tape recorder, as were all receivers and transmitters at the station. One track was reserved for WWVH time signals. A second 12 track tape recorder acted as a back-up to the first. Reels were changed at the beginning of each new radio day (0000Z).
On a panel next to the two Collins receivers was a telephone-type rotary dial with four red lights above it. If digit 1 was dialed, the first red light would be lit, indicating our MF xmtr was on 500 kc in the A1 mode; if digit 2 was dialed, the second red light would be lit, indicating the transmitter was on 500 kc in A2, or MCW (modulated CW), mode. More on A2 later. Dialing digit 3 shifted the transmitter to 440 kc, A1 mode which was NMO’s working frequency. Dialing digit 4 shifted the transmitter to 512 kc, A1 mode (more on 512 kc later).
I’m not sure if this was against FCC or ITU regulations, but our 500 kc transmitter was ALWAYS set to the A2/MCW mode when I was at the key; I hope there is a statute of limitations concerning this possible violation! I loved the musical notes A2 produced. Since our transmitter site was at least 5 miles away, on the 4000 foot peak of the Koolau Mountains, we enjoyed full duplex transmission.
MF CW Radio Log
At a right angle to the operators desk was a typewriter containing the MF CW radio log. During radioman school, we were instructed to attempt to log every signal we heard on 500 kc (an impossible feat), but at worst, make an entry every 5 minutes according to ITU regulations. If no signals were heard within a 5 minute period, which would never happen at night, then one would enter:
NO SIGS 500 2308Z NO SIGS 500 2313Z BEGIN SILENT PERIOD 500 2315Z END SILENT PERIOD 500 2318Z KPH KPH KPH DE WNKL WNKL AMVER 425 K / WNKL DE KPH R UP / UP / EE / EE 500 2320Z NO SIGS 500 2325Z
Thus, whatever we heard would be typed directly into the log. At right angles to the log typewriter, was a second typewriter which was used to copy traffic from ships to NMO: OBS, AMVERS (Automated Merchant VEssel Reporting), Dead Head Medicos (medical reports handled free-of-charge), and other non-commercial traffic. By U.S. law, Coast Guard stations cannot handle commercial traffic, for that would take revenue away from the commercial stations.
Keys & Shifts
Sitting on the ops desk was a Vibroplex chrome-plated bug and a cheap straight key screwed onto a thin sheet of plexiglass. I, of course, only used the straight key. Shifts at NMO ran like this: 12 hours on; 12 hours off; 12 hours on; 72 hours off.
The day watch started at 0700 and ended at 1900 (local); night watch ran from 1900 to 0700 the next morning…yawn. During my off hours, I rebuilt an old wooden sailboat that doubled as my home. That enabled me to collect money from the Coast Guard for off-base housing. What a life, huh?
No Love For 500 Kc
No one on my shift had any particular love for the 500 Kc position. “What fools!”, I thought. Even though we were supposed to rotate positions every 3 hours, I volunteered to remain at the 500 position for the full 12 hour shift, especially during the night watches. I loved it!
It was from this modest console that I would spend the next three years of my life. The things that I copied would, at times, amaze me, cause me laugh so hard I would fall out of my chair, or cause me to break down weeping.
To this day, I cannot forget the ship’s op with whom I was working a distress. He stayed at his key while his ship broke up in heavy seas; his transmitter emitted a scream at the moment the ocean flooded his radio room shorting the batteries and radios.
Why 600 Meters?
I have researched the literature in order to find an answer to this question, but have found nothing. I tend to think that this particular wavelength, 600 meters, became the standard by accident rather than some body of policy-makers deciding that it was to become the worldwide calling and distress frequency.
Maybe the nature of early equipment might be the reason this wavelength became the standard; the length of the antenna on some early transmitters dictated the center frequency of their very broadband signal – given that the antenna would run the length of the ship might have a bearing on 600 meters became the international CW wavelength.
Excellent Nighttime Propagation
Regardless of whether it was by accident or choice, what was handed down to us was a wavelength with excellent evening propagation. Starting at about 2100 local time, 500 kc would come alive. Any ship or shore station within 3000 to 4000 mile range could be heard by an excellent combination of ground wave and sky wave – nothing was missed within this radius!
Shore stations of more than 5000 miles were easily copied. Australia and New Zealand boomed in nightly. Daytime propagation consisted of only ground wave so 300 to 500 miles was the maximum range possible. Most daytime traffic was passed on the HF channels.
The idea of combining a distress frequency and a calling frequency was an excellent one. It insured no distress calls would be missed, and at the same time everyone knew where everyone else was at. No need to search various frequencies looking for a particular ship or shore based station. The result was a worldwide party line. If you sent so much as a single dit everyone would hear it.
Single Dit Stifiles Sleep
Ships operated on either a one-op or two-op schedule so our broadcasts coincided with these schedules. Shore stations had to remain on the air 24 hours a day. Late nights could become a bit of a bore for some shore ops – heavy eyelids and such. So out of boredom, or maybe by accident, a single dit would ring across the Pacific only to be answered by another dit possibly several thousands of miles away. Then all hell would break loose. Every shore station and any ships with an on-duty op would be sending dits. For several seconds, 500 kc sounded as if one hundred or more carriers were ‘ditting’ away! As quickly as it started, it would fade away.
All At Once
A variation of this was someone sending a single GE (good evening). It would of course, be impolite not to respond in kind, so someone else would answer with GE. Within a half second at least one hundred GE’s would flood the frequency! My log entry would look like this:
GE / GE / GE / GE / GE / (OPNOTE: AT LEAST 100 GE’S SENT)……500 ………1123Z
Some ‘Coasties’ were unhappy with their duty assignment locations. Examples of these were Alaska, or some LORAN station in the middle of the Pacific, or on board a patrol ship. They made their sentiments known to the world. One op would send an F, a second disgruntled Coast Guardsman would follow with a T, only to be followed by by a third CG op sending G – three Coasties seperated by hundreds of thousands of miles of water expressing their thoughts as one. The acronym FTG stood for a very common expression in the Guard: F___ The Guard. In the log it was recorded as:
Needless to say, the Commanding officer (‘The Old Man’) of NMO, upon reviewing the log the following day, would attach a nasty note expressing his displeasure at seeing such entry in an Official U.S. Government Legal Document. The Chiefs on the other hand, would give out a hardy laugh and express their delight that this acronym was still travelling the airwaves.
Steady CW Stream
After 2100 local time, there would be a steady stream of CW on 500 kc. Ships calling shore stations or other ships:
KOK KOK KOK KOK KOK KOK KOK KOK KOK KOK (making a pest of himself)
DE (in other words: ‘who the heck is calling me?’)
DE KNLS TR K
KNLS DE KOK R UP 485 K
OK 485/480 UP
Translation: The ship KNLS, ignoring the usual 3X3 callsign format, was going to endlessly call the shore station KOK until he got some attention. KOK interrupted him with a simple DE after which KNLS told him he had a travel report (TR). KOK’s answer was ‘Roger’. I’ll transmit on 485 kc to which the ship answered: ‘Okay, you transmit on 485 and I’ll transmit on 480 – let’s go up. (up in wavelength that is, not in frequency). Traditions are hard to break. By the way, KOK was a shore station located on a beach on Oahu.
TTT TTT TTT CQ DE ZLD ZLD CYCLONE WARNING NR 15 QSW 428 AR(These types of broadcasts, prefaced with TTT or XXX, will be discussed in Part 4.)
Yet another example:
CQ CQ CQ DE WNOP WNOP ANY ONE HV 2100Z SOUTH PACIFIC WX? K
WNOP DE XSU GE WILL GIVE 2100 WX ON OUR 2200 BCST K
OK TKS OM SU
This went on and on throughout the night, but it was very orderly. One can see that each series of transmissions ended with a ‘dit dit’. This is recorded as EE. Some amateur radio operators thought they actually invented this ‘prosign’.
4A – PROCEDURES
The first duty of an operator coming on watch is to check his clock against WWV per ITU regulations. Certain operations on 500 kc have to be timed down to the second. In the log it was recorded as:
- OBTAINED WWVH TIME TICK – CLOCK CORRECT…2500KC….0900Z
Because of the steady stream of signals on 500 kc, a weak station sending a distress message might not be heard. At one time, calls AND traffic were passed on 500 kc. There was no shifting to working frequencies to pass messages. Thus, silent periods (SP) were created.
These consisted of two three-minute intervals in which no one transmits worldwide. Volume controls are turned up; ears are pressed to the speaker grill; one’s breath is held, from minute :15 to minute :18 and again from minute :45 to minute :48. Even if traffic is being passed on working frequencies, it too, would stop. For example, if I were sending the weather report on 440 kc:
- …HIGH PRESSURE 1028MB 35.8N 132.3W BT CQ CQ CQ DE NMO AS SP SP AR
at which point myself and my listening audience would shift back up to 500 for that particular 3 minute interval.
Lids And SP
Pity the station whose clock is off or who forgets the SP, for a half dozen stations might jump on him:
- VLA VLA VLA DE 3FWR 3FWR K
- QRT SP SP
- OK SRI
- SP SP
Meaning: The ship 3FWR calls the shore station VLA – someone breaks in to tell him to stop transmitting. He responds with ‘sorry’ and is still scolded. Says he’s sorry a second time and is scolded again. Someone, somewhere in the Pacific was more direct and to the point:
- JNKB JNKB DE FHWN FHWN
- SHUT UP SP (sent at 30 wpm)
The last 15 seconds of a SP was set aside for safety and urgent preliminary transmissions.
4B – BROADCASTS
From the lowest to the highest priority, the following types of broadcasts existed:
- CQ – meaning ‘Hello All Ships and Stations’ sent in a 3X3 format :
CQ CQ CQ DE FUM FUM FUM WX AND TFC LIST QSW 430 AR
Here, the shore station FUM, French Navy Tahiti, makes an announcement that he’ll be sending the weather and his traffic list on 430 kc. The CQ is the most common broadcast announcement. One CQ will go out every few minutes.
TTT – This is the prosign for a safety broadcast: storm warnings, navigation hazards, or anything involving the safety of shipping:
- TTT TTT TTT CQ DE ZLW ZLW ZLW CYCLONE WARNING NR 38 QSW 475 UP
Each T is sent longer than usual in order to provide a very distinctive sound. During the last 15 seconds of a silent period, a half dozen TTT’s would be going out. In particular, the shore stations running around the perimeter of Australia would sent the same TTT, one station following the previous station. Everyone in the Pacific wanted to be the first one out with their TTT announcement instead of waiting for a station 1000 miles away to finish, so many time they’d all go out at once. What a mess!
XXX – This prosign is indicative of an urgent broadcast where shipping and lives might be in danger (the CO might order the auto alarm sent prior to the preliminary announcement on 500 kc):
- XXX XXX XXX CQ DE NMO NMO NMO HURRICANE WARNING QSW 440 AR
Again, each X is drawn out so as to provide a very distinctive sound. This, as with the TTT announcements, went out during the last 15 seconds of a silent period. Those sending a TTT were supposed to give way to an XXX . Remember, everyone is working duplex or full QSK – you MUST be able to hear anyone sending under you.
SOS – The darkest hour of an ops career is when the Captain of the ship enters the radio shack, hands the op a piece of paper, and says ‘Send the SOS – here’s our position’. International procedures dictate *every* step that the operator will then take.
4C – DISTRESS PROCEDURES
Auto Alarm (AA): Twelve 4-second dashes, each dash followed by a one-second pause, sent in A2 (modulated CW). ITU regulations demand that every ship carry an AA decoding receiver. This decoder will only respond to AA’s sent in A2 mode.
In A2 mode, the transmitter is modulated by a tone (two meter ham repeaters ID in this manner). What you would hear on your receiver, with your BFO on, would be several tones, or harmonics – very musical and an attention getter; a station sending CW in A2 sounds like someone sending code on a piano keyboard by pressing a half dozen keys at once!
One very old book in my collection describes an easy, but archaic method of modulating a CW transmitter. A toothed wheel is rotated at several hundred RPM with a wiper, connected to the keying circuit of the transmitter, rubbing over the teeth of the wheel. Crude but effective.
The AA will activate the decoder aboard every ship within receiving distance after four correctly sent dashes are received. The decoders are designed to be a bit forgiving concerning the timing of the AA dash. They will accept, as a valid dash, a dash of between 3.5 seconds and 6 seconds in length – just in case the sending op is nervous.
As mentioned, only four correct dashes are needed, but just to be sure, ITU demands that twelve be sent. Once the AA decoder receives four dashes, its latching relay closes activating lights and bells in the radio room, the radio officer’s stateroom, and up on the bridge.
The Two-Minute Wait
The op in distress now must wait two minutes if possible. If his feet are getting wet, then he skips this step. Off duty operators aboard other ships that have received the AA, must proceed to their radio rooms. 500 kc is now in a continuous silent period until the controlling station sends:
- CQ CQ CQ DE (cs of controlling station) QUM 500 KC VA
Note that QUM means that distress traffic has ended – resume normal traffic. The controlling station is the distressed vessel. He can and does give control to the first responding shore station. If I was the first shore station to respond, then NMO would be the controlling station.
Pity ANY ship or shore station who transmits normal traffic during a distress:
- 9JBV 9JBV DE HCKO HCKO HW OM K
- QRT QRT QRT SOS 500 (sent by dozens of stations)
All traffic pertaining to the distress will be sent on 500 kc. Those not in a position to assist will move to 512 kc – 512 is the alternate calling freq when 500 is in distress use. Here is a typical distress broadcast sent at no more than 16 wpm (ITU regs):
- SOS SOS SOS CQ DE 5TER 5TER 5TER BT SOS 281751Z MV PANAMA TRADER TAKING ON WATER ENGINE ROOM FLOODED POSN 13.73N 152.55W 13.73N 152.55W NEED IMMEDIATE ASSISTANCE AR MASTER SOS
This broadcast would be followed by a 10 second long dash to aid receiving stations in getting a bearing to 5TER’s position.
Then would come the acknowledgements:
- SOS 5TER 5TER DE NMO NMO NMO R R R SOS
- SOS 5TER DE KFS KFS KFS R R R SOS
SOS 5TER 5TER 5TER DE JNA JNA JNA R R R SOS
SOS 5TER 5TER 5TER DE WNPH WNPH WNPH R R R SOS WE ARE IN POSN 11.81N 151.32W
CHANGING CSE TO UR POSN WILL GET ETA K
SOS WNPH DE 5TER R TU HERE IS MORE INFO …..
Start With SOS
The first thing you’ll notice is that all transmissions must start with SOS (ITU regulations). What happened here is that three shore stations acknowledged the distress broadcast. ITU regs state that you must send R R R SOS.
A nearby ship also acknowledged and is proceeding to 5TER’s position. The 500 op at NMO (me!) would be on the phone to the Rescue Coordination Center (RCC) passing all information. RCC would launch aircraft and also key up the AMVER computer to check for nearby vessels. Suppose the AMVER computer shows that KPLH is steaming nearby:
- SOS KPLH KPLH KPLH DE NMO NMO NMO
Would be sent every 5 mintes both on 500 kc and on all the HF frequencies.
In case no ship responded to 5TER’s distress call, 5TER might give control to NMO. We would then periodically send:
- DDD SOS SOS SOS DDD CQ DE NMO NMO NMO BT
where the DDD indicates that NMO is relaying a distress.
4D. OTHER BROADCASTS
I had mentioned that the last 15 seconds of the silent period were reserved for safety (TTT) and urgent (XXX) preliminary broadcasts. The problem was that 10 or 20 shore stations might have such a broadcast to put out and none of them knew who else would be a sending one. The result was sometimes a mess. To hear a dozen shore stations trying to send all at once:
- TTT TTT TTT CQ DE ………was extremely funny!
Some would start a bit earlier than H:17:45 or H:47:45. I would start hearing TTT TTT TTT CQ DE … sometimes as early as the last 30 seconds of an SP. Now, EVERY shore station worked duplex and everyone wanted to be the first to get their broadcast out.
The Japanese stations were always the most polite. I’d hear a New Zealand TTT and an Australian TTT and a Japanese TTT. The Japanese station would always stop his broadcast to yield to the others. Once the frequency was quiet, then the Japanese station would start his TTT ‘prelim’ again. A preliminary (prelim) broadcast is the short announcement on 500 kc telling everyone to shift to one’s working frequency for the full broadcast text:
- XXX XXX XXX CQ DE VLA VLA VLA URGENT MARINE BCST MAN OVERBOARD QSW 472 UP
is a preliminary broadcast.
The Australian shore stations were a well behaved unit even though they might crush other countries trying to send prelims. The following Aussie stations would take turns sending their prelims – as soon as one finished, the next would start:
- VII, VIA, VIR, VID, VIS, VIT, VIM, VIB.
The only New Zealand shore station I used to hear was ZLZ. Other South Pacific shore stations I heard nightly were:
- FJP – New Caledonia
- 3DP – Fiji Islands
- P2M – Papua, New Guinea
- DUQ – Samoa
- 8BB – Indonesia
- VJZ – New Britain
- FUM – Tahiti (French Navy)
- XSU – can’t remember – used to hear a lot of X__ shore stations,
- and ones from Korea, Philippines, China, Central and South America…
North Pacific West Coast shore stations that would boom in nightly included:
- NMQ – USCG Radio Long Beach, CA
- NMC – USCG Radio San Francisco CA
- NOJ – USCG Radio Alaska
- KFS – San Francisco commercial station
- KPH – another San Francisco commercial station
- KHK – Honolulu commercial station
- KOK – Southern California commercial station
To hams, 500 kc would have been a DX’ers dream, but we took the excellent conditions for granted. Keep in mind that NMO had a very long receiving antenna – a long wire over one mile in length.
Not only would there be pileups at the end of a silent period, but also at the top of each hour. That’s when the low priority “CQ CQ CQ DE … WX AND TFC LIST QSW … AR” type of prelims would go out.
So, not wanting to take a number and wait for others, prior to sending a prelim broadcast, I would always send the Morse letter I or E as a way of saying “Hey – don’t anyone else send anything because I’m running ten thousand watts in A2 mode and I’ll crush you…” or something like that.
Seriously, if I had a safety or urgent message to send at the end of a silent period, as I was sending my TTT or XXX, I’d hear other countries under me as they started their prelim and they would suddenly stop when they heard us. NMO must have put out a commanding signal to the entire Pacific for everyone to yield to us. Generally, 500 kc was very orderly and everyone was a gentleman.
4E – FREQUENCY SCHEME
Ships had a choice of using any of the following working frequencies: 425, 454, 468, 480, and 512 kc. Shore stations only had one fixed working frequency, so during an initial call on 500 kc, a shore station would give his working frequency and the ship would choose one of the above to get as close as possible (so as to work duplex):
- 3LF 3LF 3LF DE CKHB CKHB TR K
- CKHB DE 3LF GE QSW 471 K
- DE CKHB R 471/480 UP
- R UP
Here, the ship CKHB called the shore station 3LF wanting to pass a travel report (TR). 3LF has a fixed working frequency of 471 kc so the ship chose to use 480 kc. 471/480 means: “you use 471 and I’ll use 480”.
Why these particular choice of frequencies? Note that 454 kc was the old 660 meter wavelength, 480 kc = 625 meters, and of course, our star frequency 500 kc = 600 meters. If you haven’t guessed, shore stations have 3 character callsigns, and ships have 4 character calls.
Just Below Broadcast
Many folks have shown their surprise that this kind of activity was occurring, on a worldwide scale and it was just below the broadcast band. As a young pup, I knew something was lurking just below the rock and roll band. Living near NMQ (USCG Radio Long Beach, CA), I would occassionally hear an unusual on-and-off hissing sound which would get stronger the lower I tuned:
- sheeeesh shesh sheeeesh shesh….sheeeesh sheeeesh shesh sheeeesh
This was NMQ sending their CQ. My AM table top tube radio didn’t have a BFO. That prompted me to both study the code and take the cover off my AM radio to move to down to the source of this noise. Boy, did I ever ruin that radio. Thank goodness my parents bought me a Heathkit shortwave receiver – with a BFO no less!
A Minor Diplomatic Incident
One evening, while sitting the 500 kc watch and daydreaming of those lucky ops onboard their ships scattered about the Pacific, my pleasant thoughts were shattered by a broadcast from a Soviet ship:
TTT TTT TTT CQ DE UBEX UBEX UBEX BT 170930Z ALL SHIPPING WITHIN 200 KM RADIUS 030-060 DEG FROM 37.42N 174.11E USE CAUTION DUE TO MISSILE TESTING DURING THE HOURS OF …
Oh gad, he was going to send the entire text on 500 kc – that’s a no-no for just a safety broadcast. Okay, time to earn my pay as the Central Pacific 500 kc policeman – I’ll just break in by sending a couple:
He kept right on going. Okay; I’ll hold my key down for a few seconds but not too long because long dashes will activate auto alarms aboard ships.
Ah, silence at last. It will be nice:
UBEX DE NMO NMO GE OM PSE QRT ON 500 PSE QSY 512 OK IMI K
After a few seconds of silence he proceeded to send:
TTT TTT TTT CQ DE UBEX UBEX UBEX BT 170930Z ALL SHIPPING …
Oh geez, this guy gets the ‘Lid-Of-The-Night’ award. Now I’m not happy. The Cold War comes to 500 kc. I send another:
Silence results. Let’s try it again:
UBEX DE NMO QRT ON 500 QSY 512 K only to be followed by:
TTT TTT TTT CQ DE UBEX UBEX UBEX BT 170930Z ALL SHIPPING …
Now, with only 30 seconds until the silent period ends, my concern for his unlawful broadcast is quickly growing. 15 seconds, 10 seconds, 5 seconds; my log:
BEGIN SILENT PERIOD…………….500……..0945Z
OPNOTE: UBEX CONTINUING TO SEND SAFETY BCST DURING SP. SPVR NTFD. 0945Z
Having told my supervisor, I proceeded to send:
QRT QR SP SP
The ‘lid’ kept right on sending! Now my mates on the West Coast were losing their patience too – first up is NMC (San Francisco Coast Guard):
UBEX DE NMC QRT SP SP
He stops! A few seconds later (still during the silent period):
TTT TTT TTT CQ DE UBEX ….
Oh man, this nut’s got seaweed instead of brains. In jumps NMQ (Long Beach CG):
DE NMQ QRT SP SP
Even NOJ up in Alaska jumps in the brawl:
DE NOJ QRT SP……………followed by a powerful:
DE KPH QRT SP SP
The kook kept right on sending his broadcast. Finally, at minute :47, and still within the silent period, he finished. I, of course, logged everything. One thing I didn’t log was my ‘QSL’ to him after the silent period:
UBEX UR A LID
Without my callsign, and in A1 mode (I always kept our 500 kc transmitter in A1), no one would know it was me. So much for diplomacy with the Soviets.
For the most part every, ship and shore station worldwide followed the international procedures. The discipline on 500 kc around the world was amazing.
During Coast Guard Radioman school we were reminded that what was being taught to us were not Coast Guard or U.S. Government policies, but rather international rules set forth by the United Nations, and the International Telecommunications Union.
Every shipboard operator, spanning many decades, had been taught the exact procedures being presented to us. This instilled in us, an unbroken chain of tradition with those ship’s radio operators right from the start. All of us felt a deep respect toward 500 kc. There was a sense of mystery felt towards this frequency – very difficult to put into words.
My First SOS
As mentioned in an earlier part, I always sat the 12 hour, 500 kc night watch on my duty nights. I loved listening to the steady flow of calls from ships in far off waters. Even though we sat in the Central Pacific, I would sometimes even copy a fluttery East Coast U.S. shore station.
Throughout the night I would hear ghostly signals, just above the noise level, that would fade in and out from who knows where. We used a Beverage-type, long wire that stretched over one mile in length, and NMO sat in a very electrically quiet region. We were able to copy any ship or shore station anywhere in the Pacific.
The Long Dashes
One evening, feeling a bit drowsy (0200 local), I thought I was dreaming when I heard a long dash, a pause, another long dash, a pause, another long dash, a pause…..like an electric shock, adrenalin flooded through me at the speed of light – OH MY GOD – SOMEONE IS SENDING AN AUTO ALARM!
My eyes shot to the clock to time the dashes; 4 seconds on, 1 second off, 4 seconds on, 1 second off. Those 12 long dashes almost froze me. I yelled into the intercom to the chief “Auto Alarm on 500” knowing at the same time alarm bells were ringing on board every ship scattered around the Pacific within radio range of the distressed ship.
Recall that when a shipboard operator goes off watch, ITU rules dictate he leaves a receiver tuned to 500 kc with a decoder attached. If that decoder hears at least four 4-second dashes each with 1-second separation, relays in the decoder will clamp shut triggering alarm bells in the radio room, in the radio officer’s sleeping quarters, and the bridge. It warned of a distress message about to be sent on 500 kc.
Now, the two-tone AA (Auto Alarm) used on the voice SSB MF distress/calling freq of 2182 kc was common. Mexican fishing crews used them when they were drunk. But AA’s on 500 kc are never sent except when a ship is in distress.
This was the first one I’d heard since my radioman school days. I can’t put into words the terror I felt while sitting out the ITU required, 2 minute wait. Recall, that the ITU dictates every step the distressed vessel’s radio officer takes; Auto Alarm, then the 2-minute wait (if possible) for off- duty ops on other ships, woken by their Auto Alarm receivers, to race to their radio shacks to copy the distress.
Extended Silent Period
500 kc was now in an extended silent period. Someone started tuning up and was immediately pounced on by myself. ‘QRT SOS’ was all I needed to send – dead silence. One of the Australian shore stations was sending a CQ at the same time the AA went out – he must have heard the AA through his CQ for he stopped in mid broadcast. Nothing but an occasional static crash – dead silence. Throughout my brief 500 kc career, there had never been a silence like this I thought. Then it came:
- SOS SOS SOS CQ DE DJNK DJNK DJNK SOS BT MV PANAMA TRADER HULL CRACKED IN HEAVY SEAS MAJOR FLOODING 42-27N 42-27N 178-51W 178-51W NOW ABANDONING SHIP SOS BT MASTER AR K
Then came the 10 second long dash (ITU: for direction finding).
I was first – in A2 mode, I sent:
- SOS DJNK DJND DJNK DE NMO NMO NMO RRR SOS
After me, 500 kc was flooded with ships and shore stations sending sending the ITU response:
RRR SOS SOS DJNK DJNK DJNK DE NMC NMC NMC RRR SOS
- (San Francisco)
- SOS DJNK DJNK DJNK DE NOJ NOJ NOJ RRR SOS
- SOS DJNK DJNK DJNK DE NMQ NMQ NMQ RRR SOS
- (Long Beach, CA)
- SOS DJNK DJNK DJNK DE KPH KPH KPH RRR SOS
- (San Francisco)
The International Telecommunications Union dictates a strict format to follow in times of distress – from now on, every transmission must be proceeded with the SOS prosign. Along with KFS in California, NRV in Guam, a couple Japan shore stations, the radio operator aboard DJNK must have breathed a sigh of relief and taken some comfort knowing his message was heard by so many.
Once the RRR SOS replies ceased, NMO took control. I asked the standard questions for situations such as this:
- SOS DJNK DE NMO BT NEED FOLLOWING INFO
- NR OF POB (number of persons on board)
- CSE (course)
- HULL ES SS COLOR (hull and superstructure colors)
- NR OF BOATS (number of lifeboats)
- BOAT RADIO FREQS, EPIRB WX, WIND SPD ES DIR, SWELL HT ES DIRECTION, CURRENT (weather and sea data) BT SOS K
Patiently, DJNK answered each.
After getting these important answers, I had the uncomfortable task of asking:
- SOS DJNK DE NMO BT OM PSE CL KEY BEFORE U LV OK? K
SOS NMO DE DJNK WILL DO OM
Closing The Key
Every shipboard telegraph key has a switch, which when closed, will cause the ship’s radio to transmit continuously. This enables rescue aircraft to home in on the distressed vessel using their direction finding equipment. I had asked the op to close his key switch before he leaves the ship.
At the same time, our AMVER computer was generating a printout of the locations of ships transiting the North Pacific. No ships were in DJNK’s area. At least no AMVER reporting ships.
It’s possible there was a ship close to DJNK that wasn’t sending us his AMVER position reports. A very slim possibility but a chance we couldn’t ignore. I was ordered by our Rescue Center to send the DDD SOS, (i.e. to relay DJNK’s distress message from our 10 kW transmitter). In A2, I sent:
AUTO ALARM (12 four second dashes with a one second pauses) then with my hand shaking, clenching the key:
- DDD SOS SOS SOS DDD CQ DE NMO NMO NMO SOS BT BT (DJNK’s message) ANY SHIPS IN AREA DIVERT AND ASSIST SIGNED US COAST GUARD AR DDD SOS K
Dead silence reigned for minutes that seemed like hours. An awful, awful feeling of helplessness overcame me as I sat in that chair with the entire NMO crew standing in silence – all of us knowing at that very moment men were perishing in an icy ocean.
- Already we had aircraft in the air heading to DJNK’s position, so I notified him:
- SOS DJNK DJNK DE NMO NMO BT USCG AIRCRAFT LAUNCHED TO UR POSN ETA 3 HRS BT HOWS UR COND? K
SOS NMO DE DJNK HV TO LEAVE SHIP NOW TU OM FER
His transmitter had emitted a scream – yes, it actually screamed! I turned to the Chief asking “Is that…?”
“Yes, the ocean water just flooded his radio room shorting out his transmitter and batteries.”
I couldn’t accept this – the man at that key couldn’t have just perished! I sent:
- SOS DJNK DE NMO
- SOS DJNK DJNK DE NMO
At this point, the Chief put his hand on my shoulder and only said “He can’t answer you – he’s gone.”
Throughout the night, at 15 minute intervals, I continued to send the Auto Alarm and the DDD SOS to no avail. At daybreak, our aircraft reported seeing only debris; bales of hay, which was the cargo of DJNK; no lifeboats, no bodies, only debris.
Even to this day I sometimes hear, in my sleep, the scream DJNK’s transmitter emitted that terrifying and horrible night. I pray the crew of that ship rest in peace.
Copy of a Coast Guard CW Log
This part will differ from the rest as what follows will be an actual log of signals copied during a typical one hour period. During our training at Coast Guard Radioman School (Petaluma, CA) we were advised to attempt to log everything we heard.
Well, that was an impossible task due to the volume of calls which was passed nightly. Keep in mind that only short calls were permitted on 500 kc. As soon as contact was made, one was to quickly move to a working frequency. What you’ll see in the following log sample consists of only about 10 to 25 percent of the recorded signals.
The log consisted of three columns:
- actual signals copied
- the frequency
- the time
A slash / was used to indicate a break between two transmissions except when it was actually sent over the air to indicate two frequencies – you’ll see ‘454/440’ meaning ‘you send on 454 kc and I’ll send on 440 kc’ (the Morse character _.._. is actually sent).
Ships had a choice of using 425, 454, 468, or 480 kc as their working frequencies, while shore stations were only assigned one working frequency, usually near one of the above. This was done in order to be able to work in duplex with one of the above frequencies.
Everything shown will be actual transmissions except:
- When preceeded by OPNOTE (operator’s note).
- The BEGIN or END SILENT PERIOD entry.
- The NO SIGS entry (meaning no signals heard in last 5 minutes.)
Notice the generous use of ‘dit dit’. In the log it’s indicated by ‘EE’.
U.S. COAST GUARD COMMSTA HONOLULU: NMO
RADIO DAY: 17 JULY 1979 POSITION: MF CW (500KC / 600M)
- OPNOTE: RM3 J.D. HERMAN ON WATCH, OPS NML……………0800Z
OPNOTE: OBTAINED WWVH TIME TICK – CLOCK CORRECT………0801Z
VVV VVV TEST TEST DE NMO GE / GE / GE ………….500..0802Z
3WLM 3WLM 3WLM DE ZLW ZLW HW? / ZLW DE 3WLM QRU? / R 480/488 / OK UP / UP / EE / EE 500 0803Z CQ CQ CQ DE VIA VIA VIA FOR TFC LIST QSW 446 AR 500 0804Z KOK KOK KOK KOK KOK KOK KOK / DE / KOK KOK KOK KOK KOK / LID / KOK KOK KOK / DE / KOK DE FJNB FJNB DE KOK GE UP / R UP / EE / EE 500 0806Z JKPN JKPN DE JLRT JLRT / JLRT DE JKPN QTH? / NW AM 1500 KM SAILING 153 DEG OUT OF TOKYO / JLRT DE NMO PSE QSY / SRI NMO / JKPN DE JLRT UP 512 / UP 500 0807Z OPNOTE: STATIC CRASHES ARE EAR-SPLITTING TONIGHT 0810Z CLA CLA CLA DE 7XMC 7XMC K / 7XMC DE CLA GE / GE OM DO U HV SOUTH PACIFIC WX BETWEEN 20 ES 30 S W OF 180? / NOT YET - WILL HV IN 30 MIN - LSN FER OUR CQ / OK TKS / SEEU / SU 500 0814Z BEGIN SILENT PERIOD 500 0815Z VVV / SP / SRI 500 0816Z TTT TTT TTT CQ DE VIM VIM VIM CYCLONE WRNG NR 17 QSW 428 UP / TTT TTT TTT CQ DE VIS VIS VIS CYCLONE WRNG NR 17 QSW 460 AR 500 0817-18Z END SILENT PERIOD 500 0818Z FUM FUM FUM DE KNLW KNLW OBS K / KNLW DE XSU FUM QRT TIL 0900 K / R HV OBS K / OK UP 480/488 K / R UP / EE / EE 500 0820Z CQ CQ CQ DE ZDLK ZDLK BT ANI ONE HV 0700 HYDROPAC BCST? / ZDLK DE DJKV R UP 480 HW? / OK / EE / EE 500 0824Z NMC NMC DE WRTY WRTY / WRTY DE NMC GE / GE I NEED NTM NR 12-384 K / R UP 425/428 K / R UP / EE / EE 500 0827Z TTT TTT TTT DE KNLH KNLH KNLH BT HAZARD TO SHIPPING LOST CONTAINER OVERBOARD QSS 425 UP 500 0830Z OPNOTE: SHIFTED TO 425 KC TO COPY KNLH'S MSG 0830Z OPNOTE: KNLH LOST CONTAINER IN POSN 43.48N 135.81W - INFO PASSED TO RCC FOR DISTRICT 12 NTM 0831-33Z KNLH DE NMO QSL WILL PASS UR MSG TO SAN FRAN K / NMO DE KNLH R TU OM NIL VA / DE NMO SU VA / EE / EE 500 0834Z CQ CQ CQ DE CLA CLA CLA FOR SOUTH PAC WX ES NAV WRNGS QSW 470 AR 500 0835Z JNA JNA JNA DE JNTS JNTS NW ARR TOYKO K / JNTS DE JNA QSL QRU K / QRU VA / EE / EE 500 0837Z CQ CQ CQ DE KPH KPH KPH TFC LIST ES WX 512 AR 500 0840Z BEGIN SILENT PERIOD 500 0845Z XXX XXX XXX DE 9FJT 9FJT 9FJT BT ENGINE ROOM FIRE NOW EXTINGUISHED NO POWER DIW NEED ASSISTANCE 28.38S 28.38S 165.55W 165.55W / 9FJT 9FJT DE VIB VIB QSL UP 425/430 K / VIB DE 9FJT R UP / EE / EE 500 0847-49Z OPNOTE: SPVR NOTIFIED OF 9FJT'S XXX 0849Z SILENT PERIOD ENDED AT 0848Z 0850Z CQ CQ CQ DE NRV NRV NRV WX AND CG MARINE INFO BCST QSW 435 KC AR 500 0850Z NMO NMO DE KPDR OBS K / KPDR DE NMO UP 454/440 K / R UP / EE / EE 500 0854Z KPDR DE NMO GE K / NMO DE KPDR GE OBS QRV? / R AA 99 440/454 0855Z OPNOTE: RCVD OBS FROM KPDR 454 0856Z KPDR DE NMO QSL QRU? K / NIL TU OM SU VA / SEEU VA / EE / EE 440/454 0856Z CQ CQ CQ DE XJA XJA XJA FOR WESTERN PACIFIC WX QS / CQ CQ CQ DE 5JA 5JA 5JA TFC LIST AND WX QSW 4 / CQ CQ CQ DE KFS KFS KFS TFC LIST Q / CQ CQ CQ DE / 500 0900Z / LID / UR A LID / AM NOT / ARE TOO 500 0902Z XXX XXX XXX CQ DE 7JN 7JN 7JN OVER DUE FISHING VSL QSW 441 AR 500 0905Z 5LVW 5LVW DE / ? / 5LVW DE / ? DE 5LVW SRI OM NO COPY / UP 8361 KHZ / R UP / EE / EE 500 0909Z NPQM NPQM DE NOJ NOJ / NOJ DE NPQM 12 MHZ IS WASTED QSY 8 MHZ RTTY / NPQM DE NOJ OK / EE / EE 500 0912Z BEGIN SILENT PERIOD 500 0915Z TTT TTT TTT CQ DE XSA XSA XSA UNMARKED SHOAL REPORTED QSW 448 KHZ AR 500 0917Z XXX XXX XXX DE ONJK ONJK ONJK DH MEDICO CREWMAN WITH APPENDICITIS K / ONJK DE VIB UP 454/441 K / VIB DE ONJK R TKS UP / EE / EE 500 0917-18Z END SILENT PERIOD 500 0918Z
You may have noticed that the exchanges were short with operators quickly moving off 500 kc to a working frequency. There is some informal procedure with generous use of pleasantries such as TU (thank you), TKS (thanks), SU or SEEU (see you), OM (old man), GE (good evening) and of course the ever-present ‘dit dit’. Note that the prosign VA is the like the ham’s SK. The 0900 hours entry was typical for the top of the hour – a dozen CQ’s being sent at once!
The idea of 500 kHz being an international calling and distress frequency was finalized at the 1932 Madrid Radio Conference (see Schroeder 1964). I find it a shame that amateurs never implemented the idea of a calling frequency on each band which everyone would monitor, in which short station-to-station calls and CQs could be made, with parties moving to another frequency for the QSO.
Two-meter amateur repeaters come close to this idea but operators failed to QSY off the repeater to try to work simplex. Oh well – something about Old Dogs…New Tricks.
I hoped that you enjoyed this brief glimpse into a communications era which will never again be equaled. Jeff Herman – KH6O
Gr8 story. Heading up to the Bolinas XMTR site this weekend to pass on a 1940 shipboard bug.
Very good story – I was glued to the screen. 50+ years of CW makes it even more meaningful. 73 de Bob KH6KG
Jeff, I found this article very interesting and would love to hear more of your adventures!
Jeff will probably never see your comment. Jeff gave me permission to reprint his story here.
Thanks for wonderful article!!
Was a marine op. Have heard NMO send AA sig and rpt ships SOS. Woke
Everyone up in middle of night. Remember ships name (lake Sopra) never
Been able to find out any about that ship. NMO gave our latitude and
Longitude but it was East and we were West. Old. Man about flipped
As he watched me copy msg.. NMO was so strong about blew speaker.
I sailed during WW II and for abt 5/6 years. Stopped in one time at KoK
When they were in Cerritos and they let me Qso with a ship. Thrill of
My life to work that big powerful station. All gone now replaced with
A shopping center. My call is N6DJ. Thanks for your wonderful article!!
Fantastic story! n3umw