NVIS Loop Antennas

////NVIS Loop Antennas
NVIS Loop Antennas 2017-01-11T09:31:57+00:00

SMC offer both Mobile and Fixed NVIS (Near Vertical Incidence Skywave) Antennas.

Below are some examples of the range we offer. Please contact us for a quote or for more information.

Mobile NVIS Loop Antenna

Mobile NVIS Loop Antenna

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 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.
Other versions are available for:

  • Vehicle roof-bar fitment with a ‘fold-down’ facility
  • Side mounting on the vehicle.

The standard loop roof bar attachment is designed for roof barMB8Z4693s 32mm x 22mm in cross section. However attachments can be manufactured to suit your individual requirement.

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.

Mobile HF Loop Antenna


Mechanical Specs

SpecsInformation
TX Power Input Range1.5-200 Watts PEP
Continuous TX CW/Data Power80W
Number of operating channelsUnlimited
Non-Volatile Channel Memory Addresses170 (165 TX, 5 RX)
Input Impedance Range50 ohms
VSWRTypically 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 Current230 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 CableRG58 5m in length
Power Cable2 Core screened, 5m in length

Fixed NVIS Loop Antenna

Fixed NVIS Loop Antenna

Fixed Solid Element

Fixed Wire Element

SMC have two versions of fixed station loop antennas  available, which operate on both NVIS and long distance sky-wave propagation modes across 3-30MHz:

  • A wire element loop with 3m sides
  • A solid element loop with 2.5m sides

Both offer similarly high efficiencies. These are ideal for use where space is limited, and rival the performance of much larger wideband HF wire antennas

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.

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.



Technical Spec

SpecsInformation
TX Power Input Range1.5-200 Watts PEP (3-500w PEP version also available)
Continuous TX CW/Data Power80W (200w for 500w PEP version)
Number of operating channelsUnlimited
Non-Volatile Channel Memory Addresses170 (165 TX, 5 RX)
Input Impedance Range50 ohms
VSWRTypically 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 Current900 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 CableStandard 50 ohn coaxial cable plus DC feed 3m in length

Download Spec Sheet/information PDF