VIGILANT AUTO ALARM

---

SPECIFICATIONS:

Type : TRF receiver
Frequency range: 500 KHz only
Modes: CW and MCW
Mains Power input - ?
Weight - ?
Dimensions - 97cm H x 35cm W x 31cm D.
Comment: This was a 500 KHz receiver to detect any ship which transmitted distress alarm  using an autokeyer. It would ring a bell upon the receipt of an emergency alarm which consisted of 12, spaced, long dashes.It was superseded by the Seaguard auto alarm. The Vigilant used a vibrating reed to feed a synchronous motor whereas the Seaguard employed a Notch Filter oscillator. Later versions of the Seaguard were entirely thermionic valve  abandoning the electro-mechanical timing system.

While the auto alarm transmission was twelve, four dashes spaced one second apart  the Vigilant only needed to receive three consecutive correctly spaced dashes before it raised the alarm by ringing bells in the R/Os cabin and on the ship's bridge. In contrast, the Seaguard required four dashes before it rang the bells. The bells were bolted to the bulkhead immediately above the R/O's bunk. It was not a nice way to wake up.

Also looking for a mnual on behalf of Roger Taylor, Contact: jerry.proc@sympatico.ca

Vigilant photo courtesy E-bay.com

---

Contributors and Credits:

1) http://www.rnmuseumradarandcommunications2006.org.uk/MERCHANT%20SHIPS%20AND%20RFA%20FITS.pdf (site now unreachable)
2) http://www.shipsnostalgia.com/archive/index.php?t-44509.html
3) Roger Taylor  <chelseacottage@btopenworld.com>
 

Feb 6/26