Mobile NVIS Loop Antenna - South Midlands Communications Ltd

Mobile NVIS Loop Antenna
The NEW Rugged Loop, designed with strength and durability in mind.
Traditional vertical ‘whip’ antennas fitted to vehicles for high frequency communication suffer from a ‘skip zone’, where
little or no communication is obtainable in a given area.
The SMC Mobile HF Loop Antenna, developed for NVIS (Near Vertical Incidence Skywave) communication across 3-15MHz,
overcomes these limitations by having high radiation efficiency
and no skip zone whatsoever.
Capable of automatically tuning across its frequency range in less than a 50th of a second, it is compatible with virtually
any HF transceiver including frequency hopping types without the need for a separate control.
Based on the tried and tested SMC mobile NVIS loop which is in use by organisations throughout the world, this latest
version incorporates a significant upgrade to ruggedized thick-walled
tubing for performance and durability.
Deployed
Frequency Range: 3.0 - 15.0 MHz
Unit Weight: 15kg excluding fixings
Retracted: 1.7m x .95m x .12m
Deployed: 1m height
\\ Strengthened
Tubular Structure
Specs
Information
TX Power Input Range
1.5-200 Watts PEP
Continuous TX CW/Data Power
80W
Number of operating channels
Unlimited
Non-Volatile Channel Memory Addresses
170 (165 TX, 5 RX)
Input Impedance Range
50 ohms
VSWR
Typically less than 2:1 when tuned, (3:1 max)
DC Operating Range
+10.0V to 18.5V DC, (+13.8 V DC nominal) 24V DC
nominal also available on request
DC Current
230 mA average
Initial tuning response time (initial memory
setting only)
2 - 20 sec per channel
Recurrent tuning response time (on-air use
inc. freq hopping)
Typically less than 10 ms per channel
Operational Temperature
-35° to +70°C
Coaxial Cable
RG58 5m in length
Power Cable
2 Core screened, 5m in length
In receive mode, for non-scanning/frequency hopping modes the antenna is factory-set to
automatically store its tuning settings for the last tuned transmit frequency for greater receive
efficiency. However, if pre-defined by the user upon ordering it may alternatively be factory-set for
the loop to operate ‘un-tuned’ in receive mode to allow wide-band reception for scanning modes
such as ALE (Automatic Link Establishment) reception.
Colour options. More
available on request.
The front edge of the loop is angled to deflect low
overhead obstacles such as small tree branches.
The standard loop roof bar attachment is designed for roof
bars 32mm x 22mm in cross section. However attachments
can be manufactured to suit your individual requirement.
Test Specification:
MIL-STD-810E: Method 514.4:
Vibration, Categorry 8 - Ground Mobile, to Figure 514.4-16
Minimum Integrity Test General.
Other versions are available for:
»» Vehicle roof-bar fitment with a ‘fold-down’ facility
»» Side mounting on the vehicle.
South Midlands Communications Ltd. SM House, School Close,
Chandlers Ford, Industrial Estate, Eastleigh, Hampshire, SO53 4BY ENGLAND
Tel: +44 (0)23 8024 6200 - Fax: +44 (0)23 8024 6206 - Email: sales@smc-comms.com
NVIS Loop Data Sheet Additions
Typical 3MHz
Azimuth Pattern
Representative near-field azimuth radiation
patterns, taken at a distance of 16m, from the
NVIS loop when mounted on a 4x4 vehicle.
Outer scale represents -25dBm measured
level with 10W RF fed to the loop system.
Low frequency 3D radiation pattern, shown
with loop mounted in the same plane of the
vehicle, i.e. front to back
The radiation pattern presented by the
loop at low frequencies gives maximum
radiation in an arc from the front of the
vehicle, over the vehicle (thus giving
excellent NVIS performance) and to the
rear of the vehicle. At higher frequencies, a
typically ominidirectional radiation pattern
is presented giving all-round long-distance
coverage.
Typical 15MHz
Azimuth Pattern
Fixed Station Loop Antenna
Operating both NVIS and Long Distance Sky Wave
As well as the compact mobile HF loop, two versions of fixed station
loop antennas are also available, which operate on both NVIS and
long distance sky-wave propagation modes across
3-30MHz.
ge: 3.0
n
ncy Ra
Freque
- 30.0
MHz
The two versions are a wire element loop with 3m sides, and a solid
element loop with 2.5m sides, each offering similar high efficiency.
These are ideal for use where space is limited, and rival the
performance of much larger wideband HF wire antennas.
Example of the Wire Element Loop
Example of the
Solid Element Loop
Colour options. More
available on request.
Secure locking catches
ATU
Like the mobile loop, the fixed station loop is capable of automatically tuning
across its frequency range in less than a 50th of a second, it is compatible with
virtually any HF transceiver including frequency hopping types without the need
for a separate control.
1200
Other sizes can be made upon request.
Design changes may be made at any time.
2750
2500
Specs
Information
TX Power Input Range
1.5-200 Watts PEP (3-500w PEP version also available)
Continuous TX CW/Data Power
80W (200w for 500w PEP version)
Number of operating channels
Unlimited
Non-Volatile Channel Memory Addresses
170 (165 TX, 5 RX)
Input Impedance Range
50 ohms
VSWR
Typically less than 2:1 when tuned, (3:1 max)
DC Operating Range
+10.0V to 18.5V DC, (+13.8 V DC nominal) 24V DC nominal also
available on request
DC Current
900 mA average
Initial tuning response time (initial memory
setting only)
2 - 20 sec per channel
Recurrent tuning response time (on-air use
inc. freq hopping)
Typically less than 10 ms per channel
Operational Temperature
-35° to +70°C
Control Cable
Standard 50 ohn coaxial cable plus DC feed 3m in length
In receive mode, for non-scanning/frequency hopping modes the antenna is factory-set to automatically
store its tuning settings for the last tuned transmit frequency for greater receive efficiency. However,
if pre-defined by the user upon ordering it may alternatively be factory-set for the loop to operate ‘untuned’ in receive mode to allow wide-band reception for scanning modes such as ALE (Automatic Link
Establishment) reception.
South Midlands Communications Ltd. SM House, School Close, Chandlers Ford, Industrial Estate, Eastleigh, Hampshire, SO53 4BY ENGLAND
Tel: +44 (0)23 8024 6200 - Fax: +44 (0)23 8024 6206 - Email: sales@smc-comms.com