What is SWR?
The Standing Wave Ratio (SWR) is a measure of how well an antenna is matched to the transmission line and the transmitter. When an RF signal travels along a transmission line and encounters a mismatch, some of the energy is reflected back, creating a standing wave.

At points where the incident and reflected waves are in phase, their voltages add to form a maximum voltage, called the voltage antinode (Vmax). Where they are out of phase, the voltages subtract, forming a voltage node (Vmin). Other points along the line have voltages between these extremes. This resulting wave pattern is called a standing wave, and the SWR is defined as the ratio of the voltage at an antinode to that at a node:

SWR=Vmin/Vmax

In RF measurements, the SWR measured using a slotted line or other methods can be used to calculate the reflection coefficient and absorption coefficient of materials.

Why SWR Matters
For RF systems, impedance matching is crucial. A low SWR ensures that most of the transmitted power is radiated by the antenna rather than reflected back to the transmitter. In broadband systems, SWR can vary across frequency, so the goal is to achieve good impedance matching across the entire operating range.

Ideal SWR: SWR = 1 means perfect matching; all transmitted power is radiated, with no reflection.
SWR > 1: Indicates some power is reflected back, potentially heating the feedline and, at high levels, damaging the transmitter.
Common SWR Requirements and Measurement

Typical targets: Mobile communications often require SWR < 1.5, while many applications aim for SWR < 2.0.
Measurement tools: SWR meters, vector network analyzers (VNAs), or antenna analyzers are commonly used.
Adjustment methods: Antenna tuning or matching networks can improve impedance matching and reduce SWR.

Why Do Standing Waves Form?

Ideal case: If the transmitter output impedance, transmission line characteristic impedance, and antenna input impedance are all equal (typically 50Ω or 75Ω), all energy flows to the antenna with no reflection. Only a forward traveling waveexists on the feedline.
Practical case: Antenna impedance varies with frequency, environment, and installation, making perfect matching difficult.
Mismatch and reflection: When impedance is mismatched, part of the energy cannot be absorbed by the antenna and is reflected back toward the transmitter.
Formation of standing waves: The reflected wave combines with the incident wave, creating points of maximum and minimum voltage along the line — the “standing wave.”
SWR quantifies the severity of this mismatch and reflection.

How to Calculate SWR
SWR is often expressed as a ratio like 1.5:1 or 2:1 (usually we just say “SWR = 1.5”).

Formula using reflection coefficient Γ:
SWR=1+∣Γ∣/​1−∣Γ∣

where ∣Γ∣ is the voltage reflection coefficient (ratio of reflected voltage to incident voltage), determined by how much the load impedance differs from the line impedance.

Intuitive formula using impedances:
SWR=Zload/Zline or Zline/Zload,take the larger value

Example: If the feedline is 50Ω and the antenna is 100Ω, SWR = 100/50 = 2:1. If the antenna is 25Ω, SWR = 50/25 = 2:1. The further the impedance deviates from the line, the higher the SWR.

How to Improve (Lower) SWR
The key to improving SWR is improving impedance matching:

Use a properly designed antenna: Ensure it operates well within the target frequency range.
Use an antenna tuner: This device inserts a variable matching network between the transmitter and antenna, lowering the overall SWR on the feedline. Note: it does not change the antenna’s inherent SWR but protects the transmitter.
Adjust antenna dimensions: For single-frequency antennas (like dipoles), fine-tune the element length to achieve resonance at the desired frequency, minimizing SWR.
Ensure solid connections: Check connectors for tightness, oxidation, or moisture.
Consider the installation environment: Keep antennas away from metal objects and walls and ensure sufficient height, as surroundings can significantly affect impedance.
Summary
SWR is a key “health indicator” of an antenna system, showing how efficiently energy is transmitted from the transmitter to the antenna. Low SWR means high energy transfer efficiency and a safe, stable system. Measuring and monitoring SWR is fundamental for any RF system, especially for transmitters.

For sale: Hughes Jupiter SMC, LHCP and Modems

We have access to the following Hughes Jupiter inventory available for immediate sale:

    Qty 6 – Hughes Jupiter SMC (240 msybl)
    Qty 49 – Hughes Jupiter Modem HT2010
    Qty 87 – Hughes Jupiter Modem HT2300
    Qty 91 – Hughes Jupiter 2 LHCP 2.8 W Ka-Band Tx/Rx Outdoor Radios

Sales, Satcom Solutions Inc.
Cell: 732-810-9919
Skype: satcomsolutionsinc
Web:  https://satcomsolutions.org/

For sale: iDirect Evolution HUB equipment

We currently have iDirect Evolution HUB equipment available, including XLC-11 and XLC-M line cards, as well as 15000-series HUB hardware, suitable for network expansion, redundancy, or spares.

Sales, Satcom Solutions Inc.
Cell: 732-810-9919
Skype: satcomsolutionsinc
Web:  https://satcomsolutions.org/

Wanted: 0.74m Antennas by Skyware Global and resold by Hughes. Qty=100

All antennas are manufactured by Skyware Global and resold by Hughes, with the following part numbers of interest:

    .74 m Ku-Band – P/N 1500439-0016
    .90 m Ku-Band – Antenna P/N 1506560-0031
        Reflector: 1506560-0046
        Az/El Mount: 1506561-0041
    .98 m Ku-Band – P/Ns 1504178-0031 and 0800-3281

Satcom Solutions Inc.
Cell: 732-810-9919
Skype: satcomsolutionsinc
Web:  https://satcomsolutions.org/

I wish you all a Happy New Year

I have worked today to update the list of satellites used in all the dish pointing calculators etc.

First I downloaded an up-to-date list of the 2 line elements for the geosats. Then converted then to orbit positions. Then updated all the relevant files on my server PC.

List of satellites updated

Legacy list of 2-line elements updated

2-line elements calculation updated

Print out a list of all your visible satellites with az-el angles

Please test these links. I hope they all work.

Any problems, please email me at eric@satsig.net

Best regards..

I have added one of my antenna transmit pattern cuts below.


This image shows the recorded transmit antenna elevation pattern as the elevation angle of the dish was increased and the beam moved upwards across the satellite. The antenna was approx 7.5m diameter, transmit frequency approx 6.1 GHz.

The recording starts on the left 1 deg below the beam centre and stops on the right 1 deg above beam centre.  I have annotated the vertical scale to 1.5 dB per division  to make it easy to identify the -3 dB level, shown as bold black line.

The side to side, full -3 dB beamwidth is 0.4 deg.

For interest, the first sidelobe (on the left of the display and thus this one is above the main beam) is about -13.5 dB down. The other sidelobe is -15.1 dB down. This plot was one of many pattern cuts. Not perfect sidelobe balance in the vertical plane yet, but fixable with several more steps by tilting the top of the subreflector by 1mm, either in or out, depending on whether it is a cassegrain or gregorian subreflector.

A hint for anyone doing anything like this: Always record patterns with the antenna elevation going upwards or from left to right in azimuth (as viewed from behind the antenna) . You will than avoid confusion later when studying the plots. When you walk round to the front of the dish it is important to visualise where the high point of the first sidelobe ring is located.  Read more here:  https://www.satsig.net/sub-reflector-alignment.htm

Antenna beamwidth calculator

Here is a link to an antenna beamwidth calculator:
https://www.satsig.net/pointing/antenna-beamwidth-calculator.htm
Note that your results depend on the way the feed (and sub-reflector) distributes power across the dish surface.

An evenly illuminated dish will give a narrow main beam but will have high (poor) sidelobe spill-over levels. The spill over increases noise from the ground.

A tapered illumination with low levels at dish edge will have a wider main beam but low sidelobes and low noise from other satellites and the ground.

Achieving required gain, noise temperature and simultaneous low sidelobes is a tricky compromise!.

Antenna Pointing Accuracy – Definition, Measurement, and Calculation
In the technical specifications of satellite communication antennas, the parameter antenna pointing accuracy is almost always specified. Typically, it is expressed as: Antenna Pointing Accuracy ≤ 1/10 of the Half-Power Beamwidth (HPBW)
What Is Antenna Pointing Accuracy?
Basic Concepts
Before discussing pointing accuracy, it is necessary to understand several related fundamental concepts.
• Beamwidth
Beamwidth usually refers to the Half-Power Beamwidth (HPBW) of an antenna.
It is defined as the angular separation between the two directions on either side of the main beam where the antenna gain drops by 3 dB from its maximum value (i.e., where the radiated or received power is reduced to half of the peak).

Beamwidth is the most important reference when evaluating pointing accuracy.
The narrower the beamwidth, the higher the requirement for antenna pointing accuracy.
• Beam Center
The beam center is the direction in which the antenna radiates or receives maximum power, corresponding to the maximum antenna gain.
All pointing errors are measured relative to this direction.
• Pointing Error
Pointing error is the angular difference, at any given moment, between the antenna’s actual pointing direction and the desired target direction.
• Pointing Accuracy
Pointing accuracy describes the deviation between the actual pointing direction of the antenna main beam and the desired pointing direction (the target satellite).
Pointing accuracy is not an instantaneous value, but a statistical quantity evaluated over a specified time period. It is commonly expressed as a root mean square (RMS) error.
In essence, pointing accuracy measures how accurately an antenna can point toward a theoretically calculated direction (in this case, the satellite’s theoretical azimuth and elevation angles) under open-loop conditions.
In one sentence: pointing accuracy indicates how precisely the antenna can be aimed at the target.
The main factors affecting pointing accuracy include:
Antenna installation accuracy (base leveling, azimuth reference)
Calibration accuracy
Resolution of encoders or sensors
Structural deformation under gravity and steady wind load
• Tracking Accuracy
Tracking accuracy refers to the performance of the antenna’s automatic servo control system in maintaining alignment with a moving target (such as a satellite) during operation. It measures the error between the actual beam center and the satellite’s real-time position during closed-loop tracking.
Factors affecting tracking accuracy include:
Servo system response speed
Control algorithms
Beacon receiver sensitivity
System latency
Dynamic wind loads (gust-induced vibration)
Mechanical backlash in the drive system
Why Is Pointing Accuracy Important?
• Maximizing Antenna Gain and Ensuring Link Quality
Using the most common parabolic antenna in satellite communications as an example:
A parabolic reflector achieves high gain by concentrating electromagnetic energy into the main beam.
If the beam center is not precisely aligned with the satellite, the transmitted or received signal deviates from the region of maximum gain, resulting in reduced signal strength (carrier-to-noise ratio, C/N) and degraded communication quality, potentially even causing link outages.
For example:
For an antenna with an HPBW of 1°, a pointing error of 0.5° may result in a gain loss exceeding 3 dB.
• Avoiding Adjacent Satellite Interference
Geostationary orbit (GEO) orbital resources are extremely limited. The angular separation between adjacent satellites is typically only 1° to 3°.
If a ground antenna is inaccurately pointed, its sidelobes may illuminate neighboring satellites, causing uplink interference.
Uplink interference degrades the performance of adjacent satellite systems
It may also lead to serious international coordination issues or frequency disputes
Therefore, ITU-R Recommendation S.734-1 explicitly states:
For systems operating above 10 GHz, antenna pointing accuracy should be better than one-tenth of the half-power beamwidth.
This requirement is widely adopted across the industry.
Sources of Antenna Pointing Errors
The causes of antenna pointing errors can be classified into three categories:
1. Static Errors
Caused by antenna structure, installation, and environmental conditions, including:
Gravitational deformation: changes in reflector shape and feed position under gravity at different elevation angles
Installation misalignment: deviation between antenna azimuth/elevation reference zero points and true north or the horizontal plane
Thermal deformation: uneven solar heating causing differential thermal expansion
2. Dynamic Errors
Mainly caused by external dynamic loads:
Wind load: the dominant source of dynamic pointing error, inducing structural deflection and oscillation
Mechanical vibration and transient disturbances during rotation
3. Other Error Sources
Atmospheric refraction: bending of electromagnetic wave paths through the atmosphere
Satellite position error: inaccuracies in ephemeris data leading to satellite position prediction errors
Measurement and Calculation of Pointing Accuracy
For satellite communication ground stations, the most commonly used and practical method is the satellite beacon method.
Measurement Procedure
1. Satellite Selection
Select a stable in-orbit geostationary communication satellite transmitting a continuous-wave (CW), unmodulated beacon signal. The satellite’s orbital longitude is precisely known.
2. Calculation of Theoretical Pointing Angles
Based on:
Satellite orbital longitude
Ground antenna location (latitude and longitude obtained via GPS)
Calculate the theoretical azimuth (Az₀) and elevation (El₀) angles of the antenna.
3. Initial Antenna Pointing via the Servo System
Based on the antenna’s GPS-determined location, the servo control system drives the antenna to the calculated target angles. The positioning accuracy of the control system has a direct impact on the initial pointing accuracy.
4. Scanning
Perform a small-area scan around the target direction using:
Cross-scan
Conical scan
5. Signal Recording
Record the received beacon signal power during the scan.
6. Peak Detection
Identify the azimuth (Azmax) and elevation (Elmax) corresponding to the maximum received beacon power. This point represents the antenna’s actual electrical pointing direction.
7. Deviation Calculation
Compute the difference between the measured peak point (Azmax, Elmax) and the theoretical values (Az₀, El₀).

Pointing Accuracy Calculation
Practical Data Processing Steps
Data Acquisition
During the scan, record a set of data pointsi:
Azᵢ, Elᵢ: actual azimuth and elevation angles (read from axis encoders)
Pᵢ: received beacon signal power at (Azᵢ, Elᵢ)
Electrical Axis Determination
Perform surface fitting (e.g., two-dimensional Gaussian fitting) on the collected (Az, El, P) data
The peak of the fitted power surface corresponds to the antenna’s electrical axis pointing direction (Az_peak, El_peak)
Error Calculation
Azimuth error: ΔAz = Az_peak − Az₀
Elevation error: ΔEl = El_peak − El₀
Az₀ and El₀ represent the theoretical azimuth and elevation angles derived from the ground antenna location and the accurate orbital coordinates of the beacon satellite.
Pointing Accuracy Calculation
The total pointing accuracy is commonly calculated as:F_Total = sqrt( (ΔAz * cos(El))² + ΔEl² )

Satellite communication system terminals can be classified by installation type into fixed, vehicle-mounted, maritime, airborne, and Flyaway stations. Among them, Flyaway satellite communication earth stations have gained wide application in disaster relief, exploration, field investigation, and emergency response due to their convenience, rapid deployment, flexibility, simple structure, compact size, and lightweight design. Compared with handheld satellite terminals, Flyaway stations also offer significantly stronger communication capabilities.

Characteristics of Flyaway Antenna Systems
Unaffected by geographical constraints or limited deployment space
Small size and lightweight, easy to carry in a backpack or flight case
Low power consumption with advanced power-management design for harsh field environments
Rapid deployment and fast communication link setup
Supports integrated voice, data, and IP services, enabling critical communication for disaster relief and emergency operations
Typical Use Cases
Disaster Relief:
When disasters strike and terrestrial communication infrastructure is severely damaged, rescue teams rely on Flyawaystations to reach the site, report real-time conditions to the command center, and receive instructions and intelligence.
Exploration and Field Surveys:
Mobile teams often operate in remote areas with no fixed communication points. Flyawaystations enable continuous connectivity, allowing users to receive weather, geological data, and transmit local information.
Emergency Response:
Flyawaystations support rapid deployment of temporary satellite networks for beyond-line-of-sight communications during unexpected incidents.
Flyaway stations are ideal for temporary communication needs or regularly changing deployment locations where terrestrial networks are unavailable. User requirements drive the design of Flyaway solutions, including service types, data rates, operating environments, and carrying formats.

Carrying Methods:

Backpack type: weight should be within 20 kg for single-person carry

Case type: weight per case should be within 40 kg

Development Trends of Flyaway Satellite Communication Earth Stations
As users demand lighter equipment, higher data rates, lower cost, and easier operation, the development of domestic Flyaway satellite-communication terminals is moving toward miniaturization, multi-band capability, and modularization.

1. Miniaturization
With increasing component integration and enhanced processing power, the size and weight of RF modules and terminals will continue to decrease.

2. Integrated Design
Antenna, RF, and terminal equipment are increasingly designed as unified systems. Small terminals can be integrated at the antenna base, and low-power RF modules can be directly mounted on the antenna.

3. Multi-Band Capability
As satellite applications expand and lower-frequency resources become saturated, systems are shifting toward higher-frequency bands. Flyaway stations with multi-band operation better accommodate user needs. For example, the Harris 1.3 m Seeker terminal supports X-, Ku-, and Ka-band communications.

4. Modularization
With better integration, equipment can be designed as modular units—for example, RF modules with different power levels or frequency bands, and modems supporting various data rates and waveforms.

5. Easy Assembly and Disassembly
Higher integration simplifies installation. Complex subsystems—such as feed networks and RF components—can be preassembled as a single unit, reducing deployment time and technical difficulty.

6. Simplified Operation
Advancements in space technology, components, and computing have improved system performance while simplifying user operation. Flyaway stations often require only a few basic parameters to join the network, with the rest configured automatically by the satellite hub. The system becomes more complex internally so that user operation becomes easier.

7. Modular Service Access
Terminals can be equipped with modular service-access units based on user needs, reducing terminal size. Flyaway stations mainly support IP data services while also accommodating voice and video.

Flyaway equipment continues to evolve toward modular, lightweight designs, enabling easier transport and faster deployment. The expansion of available frequency bands provides users with more satellite-resource options, making satellite communication increasingly accessible. With growing communication demands—especially in temporary and emergency scenarios—Flyaway stations offer high data rates, low cost, and multi-service transmission advantages. They are expected to enjoy strong market prospects.

With continuous advances in satellite-communication technology, Flyaway stations are becoming more capable and convenient, making them a key direction of future application development.

Antesky’s Innovations
At Antesky, we continue optimizing our Flyaway-station products based on customer requirements. For example, we offer multi-band Flyaway antenna systems, designed with a simplified and user-friendly feed architecture. Users can easily replace feeds—typically with just two or four screws—making band switching faster and more efficient.

For detailed information, please refer to the instructions below for our 2.4 m Flyaway antenna with multi-feed support.

Antesky can customize replacable feed according your requirements, and bellow is C circular pol feed , C linear pol feed, X circular pol feed and Ku linear pol feed for example:

C1 C2 X Ku Feed

Antesky 2.4m Automatic Flyaway Antenna is packed in 7 boxes：

2.4m Automatic Flyaway Antenna Packing Details

Antesky 2.4m Automatic Flyaway Antenna installtation steps：

2.4m Automatic Flyaway Antenna installtation steps


If you are interested in Flyaway Antennas, welcome to contact us directly at sales@antesky.com once you are looking for such type of flyaway antenna. 0.75meter to 2.4meter are available in stock and can ship out soon.

For sale: 4.5M Receive-Only antennas
Type: SSE
Quantity: 4
Dismantled and stored in warehouse in New Jersey.

If interested please contact Phil Thomas on 1-321 327-3560

Also:

Vertex 7.3m KU-Band, fully motorized in shipping container (Florida)
If interested please contact Phil Thomas on 1-321 327-3560

1. Characteristics and Communication Requirements of LEO Satellites
Low Earth Orbit (LEO) satellites operate at altitudes of 300–1500 km. Their key characteristics include:

Short orbital period: approximately 1.5 hours per orbit;
Limited coverage: each satellite covers a small area;
High relative speed: approximately 7.8 km/s.
These characteristics present the following challenges for ground station communications with LEO satellites:

Short visibility window: a single LEO satellite is visible to a ground station for only about 10 minutes (e.g., a 500 km altitude satellite has a sub-satellite track covering ~3000 km), requiring rapid acquisition and tracking;
Signal attenuation: although the distance to the ground is short (300–1500 km), a high-gain directional antenna is still required to ensure sufficient signal strength;
High dynamic pointing requirements: the satellite’s high speed necessitates real-time beam adjustments to maintain alignment with the satellite.
2. Definition and Function of XY-Axis Satellite Antennas
An XY-axis satellite antenna (also called a dual-axis antenna) adjusts the beam direction via azimuth (X-axis) and elevation (Y-axis) rotation. Its core function is dynamic satellite tracking, ensuring the beam always points to the target satellite, maintaining communication stability in high-dynamic scenarios.

Compared with traditional single-axis antennas, XY-axis antennas offer:

Higher pointing accuracy: independent azimuth and elevation adjustment to track satellite movement in the XY plane;
Faster tracking speed: dual-axis linkage responds quickly to satellite position changes, meeting the needs of high-speed LEO satellites;
Wider coverage: covers the entire satellite visibility window, avoiding blind spots of single-axis antennas.
3. Synergy Between LEO Satellites and XY-Axis Satellite Antennas
XY-axis satellite antennas are key ground terminal devices for LEO satellite communication systems, designed specifically around LEO characteristics:

Dynamic tracking: adjusts the azimuth (X-axis) for east-west direction and elevation (Y-axis) for north-south direction. Ground stations can calculate future azimuth and elevation sequences based on satellite ephemerides (e.g., TLE data) to drive the antenna along a pre-defined trajectory, ensuring the beam always points to the satellite.
High-precision pointing: although LEO satellites are close, high-gain directional antennas are still required. XY-axis antennas use high-precision angle encoding (resolver precision ≤5”) and system error correction (e.g., gravity deformation, non-level base) to control pointing error within 10”, meeting Ka-band narrow beamwidth requirements and preventing signal degradation.
Multi-satellite switching: LEO constellations (e.g., Starlink, OneWeb) require multiple satellites to provide continuous coverage. XY-axis antennas can quickly switch to the next satellite to ensure uninterrupted communication.
Adaptation to LEO terminal requirements: user terminals require compactness and easy installation. XY-axis antennas can be integrated into vehicle-mounted, airborne, or fixed terminals. For example, OneWeb terminals adopt XY-axis phased array antennas that integrate satellite modem, LTE/3G, and Wi-Fi, providing convenient Internet access for users.
4. Key Technologies of XY-Axis Satellite Antennas
To meet LEO satellites communication requirements, XY-axis antennas incorporate:

High-precision angle encoding: resolver + RDC converter for pointing accuracy within 10”;
System error correction: calibration of encoder zero position, gravity deformation, and non-orthogonality of azimuth/elevation axes;
Composite control: PID algorithm + feedforward compensation to enhance dynamic tracking performance;
Rapid acquisition and continuous tracking: “prediction + correction” closed-loop process for fast satellite signal acquisition and continuous tracking.
5. Optimization of Antesky 1.8 m / 2.4 m XY-Axis Parabolic Antenna Terminals
Antesky 1.8 m and 2.4 m XY-axis parabolic antennas (fixed or transportable) are specially optimized in structure, control accuracy, and integration, fully meeting LEO terminal requirements:

High-gain parabolic structure
Lightweight, high-rigidity reflector with precision machining to ensure surface accuracy. Excellent beam performance across multiple bands (S, X, Ku, Ka) ensures high SNR and low BER during fast satellite passes.
XY dual-axis drive system
Azimuth (X-axis) + elevation (Y-axis) structure with high-speed servo motors and high-resolution resolvers, covering ±180° azimuth and 0–90° elevation, enabling blind-spot-free tracking.
Modular and lightweight design
Servo control units, RF front-end, and reflector modules are modular and combinable. Carbon-fiber reflectors + aluminum alloy support reduce overall weight by ~30% compared to traditional antennas, facilitating mobile terminals and field deployment.
Intelligent control and remote operation
High-performance ACU supports automatic acquisition, closed-loop tracking, and ephemeris-based predictive control. Multiple interfaces (Ethernet, serial, CAN) enable system integration, remote monitoring, status reporting, and self-diagnosis.
Seamless multi-satellite switching
Built-in satellite task management module calculates and switches to the next satellite before current signal fades, ensuring uninterrupted links and enhanced LEO satellites constellation service continuity.




Contact Us
Thank you for your interest in our XY-axis parabolic satellite antennas,which is mainly used for tracking LEO satellites. For more information on products, technical specifications, or customized solutions, please contact:
email: sales@antesky.com