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Ah - the Seaguard.

Something nobody else has mentioned:

The scuffed knuckles when spinning the knurled knob to get the wretched motor to turn.

The knob had to be pushed in to engage the mechanism and spun at the same time.

Why, oh, why, did they locate it so close to the chrome-plated escutcheon surround that one's knuckles would catch on the edge of it?

Happy memories of 55 years ago!!

Incidentally, distress communications were not specified to be sent at 12wpm.
My PMG handbooks dating from the 20's all state:

"The speed of transmission in cases of distress, urgency and safety shall not in general exceed sixteen words per minute."
 

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I think the autokeyer sent 4 dashes, any 3 of which would activate the autoalarm. The 1960's Marconi autoalarm was an electromechanical wonder, whereas the AEI one, the Q29, was all valves and relays. The sequence had to be learnt off for the PMG exam. "S1 closes, energising SA....." and so on!
The system worked great especially in winter in the Med, when you'd frequently get woken up at night by distresses in the North Sea - quite unnecessarily re-broadcast by PCH, the very powerful Dutch station.
Yes, I stand corrected, it sent 12 dashes, a consecutive 4 of which would activate the alarm.
 

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Twelve 4 seconds and 1 second spacing I was referring to the akd. Of course the auto alarm worked on any four consecutive 4 second dashes and one second spacing should operate the auto alarm.
Another point is that the auto alarm would not reject a dashes and spaces that was not exactly correct, in case the operator on the vessel in distress was sending it by hand. In fact the radio room clock is segmented to facilitate this.
It is amazing that a Seaguard is in garage in Western Australia.
 

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From those pics you can clearly see how the starting knob was ideally placed to cause skinned knuckles!
 

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I think that must be the luck of the draw. No one aimed to recruit R/Os with clumsy knuckles.
 

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Don't recollect ever skinning my knuckles when starting the A/A. I used the fingertips of my thumb and middle finger to spin the knob on the front panel; my knuckles were never in contact with the knob or the panel. Am I missing something (other than the scarring)?
 

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Just back from a spot of holiday and checked an old text-book that it is verbatim from the GTZM manual...
The Type M Vigilant AA bell circuit is latched on the third dash.
Why I thought it was four may have come from later model free-lance AA's.
Begs the question.
Was it also the same for Seaguard which I never laid eyes or knuckles on?
 

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It always seem to have been four dashes with the 'digital' auto alarms as per the attached image of a Lifeguard 3.

You can see the four LEDs that would light up when dashes were received and the line down to the Alarm lamp from the fourth LED.

Always a source of great fun in high static areas when you could watch the led's light up consecutively and then (hopefully) reset before reaching number four. (Amazing what counts as fun when you're on a 45 day trip from Brazil to Japan rolling like a b*tch with a cargo of iron ore!)

Same with the Redifon and IMR versions as I recall.

Marconi Lifeguard.jpg
 

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It always seem to have been four dashes with the 'digital' auto alarms as per the attached image of a Lifeguard N.

You can see the four LEDs that would light up when dashes were received and the line down to the Alarm lamp from the fourth LED.

Always a source of great fun in high static areas when you could watch the led's light up consecutively and then (hopefully) reset before reaching number four. (Amazing what counts as fun when you're on a 45 day trip from Brazil to Japan rolling like a b*tch with a cargo of iron ore!)

Same with the Redifon and IMR versions as I recall.

View attachment 682656
The Lifeguard 3 was a step backwards from the Lifeguard N - the N had a BFO, so you could use it as a 500 watch rx...
 

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Just back from a spot of holiday and checked an old text-book that it is verbatim from the GTZM manual...
The Type M Vigilant AA bell circuit is latched on the third dash.
Why I thought it was four may have come from later model free-lance AA's.
Begs the question.
Was it also the same for Seaguard which I never laid eyes or knuckles on?
That was certainly my recollection from studying for the PMG in the early 60s and having to be able to draw the selector circuit for the exams. In my mind, there would have to have been a change to the type approval regulations to make activation dependent on four correctly timed dashes rather than three. However, I haven’t been able to find out when the change took place - does anyone know? It’s clear from some of the replies and photos that later AAs did indeed need four dashes to trigger the alarm. Perhaps a need to reduce false alarms triggered by static?
Happy days,
gwzm
 

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Just found this drawing by Roger Bentley of the Marconi AA selector in a previous thread on SN. Shows the three relays that were latched by the selector pawls.
Happy days,
gwzm
Type700 selector A39.jpg
 

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Perhaps I can clear up the confusion a bit.

The Marconi Marine VIGILANT aka TYPE M manual is dated 1953.
The selector description has a table which indicates that after three correct dashes with two correct spaces between them the actuator is poised.
But if another dash arrives after an incorrect too short a space it will reset.
However if the third space reaches 1.6 secs the bells will ring.

I think the SEAGUARD was a horizontal version of the VIGILANT.

So - THREE DASHES!

The Marconi Marine LIFEGUARD manual of 1965 states:
"The alarm signal is actuated after registration of three consecutive correctly timed dashes and spaces, followed by a fourth dash of 3.5 sec or greater duration" (my underlining)
The meter on the front panel also indicates the number of 4-second dashes registered: 1st, 2nd, 3rd, 4th.

It complies with TSC.71 of the Ministry of Transport, reflecting SOLAS London 1960.

Mechanically and electrically interchangeable with the SEAGUARD 2.

So - FOUR DASHES

The Redifon AA1 manual of 1973 states that the selector can be internally preset to respond to three or four dashes.

So - THREE or FOUR DASHES

There you have it!!

Another related change was to the AKD sequence.

The Marconi Marine AUTOKEY manual dated 1953 states that after the distress signal it sends a 30 second long dash for DF purposes.
An addendum dated 1963 revised that to two long dashes of 11.5 seconds separated by a space of 1 second for DF purposes.

So, there you have it - again!!

E&OE!
 

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The Type M, Vigilant and Seaguard auto alarm equipment had different receivers but shared the same selector mechanisms, with only minor changes. In the Type M Vigilant the synchronous motor was controlled by pulses derived via contacts on a vibrating metal reed. On the Seaguard the motor was controlled by pulses from an electronic oscillator.
 

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Quite right Ron.

I have just found the SEAGUARD manual, dated 1958.

The selector mechanism must differ to that in the VIGILANT of 1953.

It requires FOUR DASHES.

From all this I hope we can deduce that the change from 3 to 4 dashes occurred by about 1956.

So, there you have it - again and again and again!!!!!!

Incidentally Ron, that short-lived Marconi Marine flag in your avatar - I actually have one! Rather tattered.
 

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It's a long time ago now (1969?) but from my experiences with the type approval testing of the Lifeguard N the thing that I found most interesting/impressive was the calculation and implementation of the receiver's complex AGC characteristics. Had to take out simultaneous tropical QRN and powerful QRM from nearby stations to allow the selector opportunity to detect not just the 4-second dashes but the briefest of spaces between dashes.
The type approval involved continuous monitoring of the equipment lasting one month whilst installed at a Post Office site at At Margaret's Bay, in the Dover Strait. No shortage of strong QRM there!
 
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In a heavy sea the Vigilant vibrating reed thingy could stop vibrating when the vibrations synchronized with the shuddering of the ship as it went up one side of a big wave. I sat, strapped in my radio room chair, and actually saw & heard this happen !! The mate on the 4 to 8 went bonkers with the bl++dy great bell clanging on the bridge.
Unbelievable !
We had a huge box of the vibrators in cans with valve bases in the spares cupboard. I think the regs went over the top when they specified how many spares one had to carry. [No unsavory comments required please.]
 

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Tried to make a semi-automatic key from one of those valve based vibrators for the dot side but couldn't get the beggar to go slow enough.
Hope you don't mind me clarify but this vibrator pack was for the GTZM receiver PSU's and nothing to do with the Vigilant Type M vibrating reed selector motor drive..
I must've been lucky in GTZB as I never had any trouble with the Vigilant except one with a case badly pitted from rust as it was close to the radio room port-hole !!
 
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