In the mid 80's elements of
the ADGE Data Link Buffer System (ADLBS) were installed at Saxa Vord. Some of
the work included the erection of three tall towers. The tallest tower carried
an antenna for a communications system known as IJMS (Interim JTIDS Message Specification, where JTIDS stands for Joint
Tactical Information Distribution System). Another acronym which confuses
things still further is used for the antenna on this tower, which is known as
the UKAEGIS antenna (United Kingdom Air Environment Ground Information
Segment). Two more tall Towers were
erected to carry Link 11 Antenna.
Separately,
a system called SSSB (Ship Shore Ship Buffer), designed by the defence
contractor Rockwell Collins, was also installed. The photo below shows the 2 Link 11 Towers,
the UKAEGIS Tower in the distance between them and the site of the SSSB :
The tallest structure was
the UKAEGIS Tower:
As far as I am aware it was actually mainly
used in AWACS operations. The next picture gives a slightly closer view of the
UKAEGIS Antenna:
The other two, slightly
smaller, towers, carried antenna used to transmit and receive data and voice
using Link 11 communications.
Each of these antenna was
9m long and weighed more than 500 Kg.
Link 11 communications normally
employed UHF frequencies to communicate with airborne platforms like
AEW/AWACS or, HF frequencies with
surface vessels. ADLBS handled the UHF
Link 11 communications using the antennas on the towers. The longer range HF Link 11 communications
were routed via a number of much lower antenna which were part of the SSSB; some
of the SSSB installation can be seen below :
Another view of the SSSB
masts, but from Zoom Earth:
In 1984 two concrete bases were
constructed for the ADLBS shelters, these were known as the Link 11 shelter and
the UKAEGIS shelter. The small building behind the UKAEGIS shelter
hard-standing in the photo below used to carry the old Type 13 height finder,
which was operational from Sep '57 until it was decommissioned in the middle of
1979. The base of the Link 11 Tower A can just be seen behind the Type 13
plinth.
The Link 11 comms were processed by Thorn EMI Electronics equipment in
the Link 11 shelter; the IJMS comms were handled by NATO equipment located in
the UKAEGIS shelter but were then fed through to the Link 11 shelter to be
processed - hence the references to Link 11 and UKAEGIS on the sticker shown:
The processed output was then
routed to the Thorn EMI Electronics console for display:
There were considerable problems
erecting a stable radome for the Type 93 radar but, before it was completed,
the UKAEGIS and Link 11 Shelters were moved inside its plinth (probably
in the early 90's, certainly before the autumn of 1993 when the Type 93 arrived
on site).
Before the Type 93 was installed Unst
suffered one of the worst storms in living memory, (New Year 1991/92). Devastation occurred over much of Shetland
and at the exposed Saxa Vord Top Site in particular. This next picture is from
the Saxa Voice, the Station magazine, some years later. The Link 11,
like much of the equipment on the Station, was off the air for some time. The
remains of Tower A can be seen to the left of the Type 13 plinth in the
following photo:
The extent of the damage is apparent in the next picture, of
the 4 Saxa Domes (SATCOM, HF 200, S 649 & T 93), only the SATCOM Dome was
left standing:
ADLBS was
installed at RAF Buchan,
RAF Saxa Vord, RAF Boulmer, RAF Neatishead and RDAF Faroes – originally the
sites were all stand-alone. In a subsequent upgrade, however, the five
sites were networked together so that information could be shared between
them. Then, in an effort to reduce manpower required at Saxa Vord, the
operator control functionality was re-located, so that Saxa Vord could be
operated remotely from the mainland.
The last radar was removed
from Saxa late in 2005 and the station closed in April 2006. Components
of ADLBS have since been removed from the site. However, the empty
shelters are quite possibly still within the Type 93 plinth (although its
associated radome was demolished in
2014).
I am grateful to Cyde
Walker (Thorn EMI, Racal, Thomson-Racal and Thales) and Pete Brindley, RAF for
their assistance. Nevertheless, I accept full responsibility for any mistakes.
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