Immersion RC SpiroNET User guide

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ImmersionRC 5.8GHz SpiroNET omni directional antenna

Instruction manual

Specifications

Typical impedance at 5.8GHz > 50 Ohm
SWR > <1.35 at 5.8GHz
Gain > 0.95dBic
Polarization > Left- or Right-hand circular (LHCP, RHCP)
Radiation pattern > 360-degrees
Configuration > 4-lobe skew planar
Dimensions (LxWxH) > 108x34x34mm
Weight (Grams) > 12 grams
Connector > SMA male, or RP-SMA female

Fig 1.

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ImmersionRC 5.8GHz SpiroNET RHCP omni directional antennas.

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Overview

The ImmersionRC 5.8GHz SpiroNET omni directional antenna was developed to offer
better multi-path rejection* than conventional whip antennas. The principle behind this
hinges on the use of circular polarization rather than linear polarization. Circular
polarization has the benefit that reflections change polarization and see a natural
attenuation of up to >20dB due to the polarization mismatch. This is an effective means
of canceling the negative effects of multi-path interference*.

ImmersionRC offers the same 5.8GHz SpiroNET omni directional antenna in different
configurations, which from a specification point of view only differ from one another in
terms of Left- or Right-hand circular polarization, and the use of the mating connector,
SMA male or RP-SMA female. The different configurations however do differ in terms of
esthetics, i.e. they use different color plastic to distinguish one from another. The
different configurations are listed below:

Black radome > Red cable > SMA male connector : Right-hand circular (RHCP)
Grey radome > Red cable > RP-SMA female connector : Right-hand circular (RHCP)
White/black radome > Red cable > SMA male connector : Left-hand circular (LHCP)

Directions on use

In order to gain the most benefit from using ImmersionRC's 5.8GHz SpiroNET omni
directional antennas the antennas on the transmitter and the receiver need to be of the
same polarization i.e. either both need to Right-hand or both need to be Left-hand
polarized. Do not mix different polarization antennas as that will incur a hefty penalty in
terms of range.

Both antennas should be mounted as much vertical as possible whilst making sure that
the antennas have free 'view' all around. Make sure that the antenna is not blocked by
parts of your model, for example the battery or parts of a carbon fiber frame, etc. In
practice this means mounting the antenna high up off of the center of your model, or
from the tail or front, alternatively the antenna can be mounted pointing down, as long as
it is mounted vertically.

Considering the antenna will be converting electrical currents into electromagnetic fields
it is good practice to keep sensitive electronics away from the antenna, as any
conductive piece of material will act as an antenna and couple in the electromagnetic
field potentially causing for erratic behavior. Take note that ImmersionRC's products are
designed from the ground-up to be RF hardened and to work together, so using
ImmersionRC products all around will yield the best results.

When connecting the antennas to a transmitter and receiver make sure the connector
has the proper gender, but also the proper polarity. RP-SMA female antennas will fit on
a SMA-female connector, but there is no physical contact with the inner conductor, so
this configuration will not work! I.e. always combine SMA with SMA and RP-SMA with
RP-SMA.

Take note that it doesn't matter which antenna is fitted to the transmitter and which
antenna is fitted to the receiver, they are identical and fully interchangeable.

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