See also Wavemeters and Cystals [XTALS].
Frequency standards provided the accuracy and the
stability for modern communications and led to synthesisers and
unattended W/T equipment.
Apart from internal standards in receivers such as
the CJK in the COMIST fit of the early 1960 period [which could also
supply other equipment which needed a standard but didn't have one built
in], the Type 633 SSB transceiver, and more modern equipment like the
FTA, which used either an external standard or its own built in
standard, the vast majority of equipments in the surface Fleet used an
external standard. In the submarine world, the old equipments of the
transmitters 623/619 [or TCS] and of receivers CDW/CDY [B40D/B41] were
replaced in the first place by a Dutch Van der Heem system which was
called SSA. Outfit SSA was a transceiver [the transmitter part was
called an exciter] and this unit had its own internal 1MHz frequency
standard. Later on, submarines were fitted with ICS [and RATT outfit
RWC] an had a traditional ICS frequency standard fitted as shown below.
The first standard to be fitted was the FSB and it
provided the standard for the transmitter Type 640 [and the CJK] in the
COMIST fit [see Transmitter page]. By comparison to all the others, the
FSB was a tiny piece of equipment and used the 1MHz output for
transmission and the 100kHz output for reception only.
With the introduction of the Integrated
Communication System [ICS] [see Transmitter page] came the FSA Series of
standards which continued to use the 1MHz output [although less so than
for COMIST], the 100kHz output [but now for both transmitters and
receivers] and the 5MHz and 1kHz outputs, the former used for the FTA
[recently mentioned above] and the latter for the Control System KMM.
When first introduced and installed in the Fleet,
various procedures were laid down as to their routine maintenance and
accuracy checking procedures which were to become W/T operators
functions. However, as time went by, it became obvious to all that these
machines were so ultra efficient that few if any procedures were
necessary over and above those carried out by the Weapons Electrical
Branch on a quarterly basis. For operators, complacency set in,
which turned out to be justified, and the daily/weekly checks were
abandoned. FSA outfits were generally fitted in a compartment free
from of 'turmoil' or excessive use, and the 5MHz Crystal [which was the
standard] was routed to the Communications Control Room [CCR] where it
was divided into the various outputs mentioned above.
The Table below gives descriptions and pictures of
This is where each of the FSA's were fitted.
||ICS 1 SHIPS
||ICS1 MIXED FIT SHIPS
||ICS2 MIXED FIT SHIPS
||SMALL MIXED FIT VESSELS