In short: the antenna is half of an EW
system's effectiveness. Its type decides which way and how evenly the
interference goes. Let's cover the main antenna types and when each fits.
Why the antenna matters so much
The jammer creates the signal, but the
antenna decides where it goes. The wrong antenna "dumps" power into
the ground or into empty space, and the suppression radius drops.
So antenna selection always goes hand in
hand with band
and complex selection.
Directional and omnidirectional antennas
By radiation pattern, antennas fall into
two big classes.
Omnidirectional radiate all around. They go on dome complexes to cover the space
around the carrier evenly — as in vehicle EW.
Directional concentrate power in a narrow sector. They give a larger radius in
the needed direction — the principle used by the handheld «Patelnia», which
you aim at the drone.
Polarization: linear and circular
Polarization is the orientation of the wave
in space. If the antenna's polarization doesn't match the drone's receiver,
part of the signal is lost.
Linear polarization is simple but sensitive to the aircraft's orientation.
Circular "shines" evenly
regardless of the drone's position, so for omnidirectional suppression it's
often chosen. More on this in the article on «Clover»
and «Quadrifilar» antennas.
Typical antennas in EW systems
In practice complexes use:
·
Whip — simple omnidirectional, for basic
coverage.
·
Panel — directional, for a sector with a
larger radius.
·
Helical / "clover" — with
circular polarization, for an even dome.
The choice depends on what you're building:
a dome around the car or a "beam" toward the threat.
Antenna, cable and connector — one system
Even the best antenna won't perform on a
poor path. A weak cable and connector "eat" power and overheat.
So the antenna is always chosen together
with the cable and connectors. Why joints overheat we covered
separately, in the piece on N-type
connectors.
What to choose for your task
If you need to cover the gear all around —
omnidirectional antennas with circular polarization. If you need to
"reach" a drone in a specific direction — a directional antenna.
To boost your own drone's control there are
separate solutions, e.g. the «Wizard»
antenna for Mavic. We'll help match a kit to your complex via contacts.
SWR and matching: why an antenna "underperforms"
Even a well-chosen antenna can perform
worse than expected if the path isn't matched. The key metric here is SWR
(standing wave ratio).
In plain terms, SWR shows how much of the
power actually goes on air and how much reflects back into the complex. High
SWR means loss and heat: the power warms the connectors instead of jamming the
drone.
So the antenna, cable and connectors are
chosen as one system for a specific band. Extra adapters, an unsuitable cable
or a poor connector raise SWR and "eat" range. Why this leads to
overheating we detailed in the article
on N-type connectors.
Questions & answers
How does a directional antenna differ from an
omnidirectional one?
Omnidirectional radiates all around (a dome
around the carrier); directional concentrates power in a sector (a larger
radius in the needed direction).
What is circular polarization and why is it used in EW?
It's a wave orientation where the antenna
"shines" evenly regardless of the drone's position. It's chosen for
omnidirectional suppression.
Can I put any antenna on an EW complex?
No. The antenna is matched to the band,
coverage type and path (cable, connectors). A mismatched antenna lowers
effectiveness.
Which antenna boosts my Mavic's signal?
A range-extender antenna with a booster,
for example «Wizard» on 2.4/5.2/5.8 GHz. It works with the native controller
and increases range.