Reports from NMO - MF CW at NMO

Copyright © 1994 by Jeffrey Herman All Rights Reserved.

Sitting adjacent to the HF CW position was a smaller room, enclosed on three sides in brick painted off-white. The fourth side was glass, including a sliding glass door, with a small sign glued on which simply said ``MF CW''.

This little booth of modest appearance was well out of proportion with respect to the role MF CW had played in the history of maritime communications. Also, though I'm sure not by accident, 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 rcvs, and one was ALWAYS set on 500kc. 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.

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 blatant reminder to the op 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: 4 seconds red, 1 second white, 4 seconds red, 1 second white, etc., around the entire circumference.

Now, these markings were to aid the 500kc op 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).

One's attention would next be drawn to two Collins 651S rcvrs mounted in the op's console. The top rcvr 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 which our rcvrs were zero-beat. The audio from these two receivers was fed into a 12 track reel-to-reel tape recorder, as were all rcvrs and xmtrs 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 rcvrs was a telephone-type rotary dial with 4 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 xmtr was on 500 kc in the A2, or MCW (modulated CW), mode (more on A2 later); dialing digit 3 shifted the xmtr to 440 kc, in A1, where 440 kc was NMO's working frequency; dialing digit 4 shifted the xmtr to 512 kc, A1 (more on 512 later). I'm not sure if this was against FCC or ITU regulations, but our 500kc xmtr 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.

Note that our transmitter site was at least 5 miles away, on the 4000 ft peak of the Koolau Mountains. Thus we enjoyed full duplex transmission. At a right angle to the op's desk was a typewriter containing the MF CW radio log. During radioman school we were instructed to attempt to log every signal were heard on 500 (an impossible feat), but at worst, make an entry every 5 minutes (ITU regs!). If no signals were heard within a 5 minute period (which would never happen at night) then one would enter:


Thus, what ever we heard would be typed directly into the log.

At a right angle to the log typewriter was a second typewriter which was used to copy traffic from ships to NMO: OBS, AMVERS 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.

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 During my off hours I rebuilt an older wooden sailboat that doubled as my home; that enabled me to collect money from the CG for off-base housing... What a life, huh?

No one on my shift had any particular love for the 500 position (``what fools!'' I thought), so, even though we were supposed to rotate positions every 3 hours, I volunteered to remain at the 500 position for the full 12 hours shift (especially during the night watches); I loved it! It was at 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 whom I was working a distress with - how he stayed at his key while his ship broke up in heavy seas - how his transmitter emitted a scream at the moment the ocean flooded his radio room shorting the batteries and radios...