In oilfield satellite communications, choosing the right VSAT hub station antenna size is not just an engineering decision—it directly determines network capacity, scalability, and operational cost. The most common comparison in gateway design is between 4.5m vs 7.3m earth station antennas, especially for VSAT hub or teleport applications supporting remote oil & gas operations.
This article breaks down the difference in a practical way and helps you decide which one fits your oilfield gateway strategy.
1. What is a VSAT Hub Station in Oilfield Networks? A VSAT hub station (or gateway teleport) is the central node of a satellite network. All remote oilfield sites (rigs, pipelines, desert stations) connect through it.
According to satellite ground segment design, the hub handles:
Uplink/downlink traffic routing Bandwidth allocation (TDMA/SCPC control) IP backbone integration Network monitoring & QoS control In oilfield VSAT networks, the hub is basically the “data brain” of the entire field communication system.
2. Why Antenna Size Matters (4.5m vs 7.3m) At the hub level, antenna size determines:
EIRP (transmit power capability) G/T (receive sensitivity) Total carrier throughput Number of remote terminals supported Rain fade margin (critical in Ku/Ka band oilfields) In simple terms:
Bigger antenna = stronger link + more capacity + more stable network
3. 4.5m VSAT Hub Station: Characteristics A 4.5m gateway antenna is often used for:
Strengths Lower CAPEX (cost-efficient) Faster deployment Suitable for small to medium oilfield networks Works well for regional hub or backup gateway Limitations Limited RF gain → lower total throughput Less margin under heavy rain fade (important in tropical oilfields) Not ideal for scaling large remote fleets Typical Use Cases Small oilfields (tens of VSAT terminals) Temporary exploration sites Backup or redundancy hub 4. 7.3m VSAT Hub Station: Characteristics A 7.3m earth station antenna is widely used in enterprise and oil & gas gateway hubs.
Industry catalogs show 7.3m class antennas as standard for full-featured hub/gateway operations
Strengths Much higher antenna gain Supports higher carrier bandwidth Better uplink power efficiency Strong rain fade resilience Supports hundreds of remote VSAT terminals Limitations Higher CAPEX and infrastructure cost Requires more robust foundation and space Longer installation and alignment process Typical Use Cases National or regional oilfield hub stations Offshore + onshore integrated networks High-throughput SCADA + voice + video systems Multi-field satellite backbone hub 5. 4.5m vs 7.3m: Technical Comparison
Feature 4.5m Hub Station 7.3m Hub Station RF Gain Medium High Throughput Capacity Low-Medium High Remote Terminal Scale Tens Hundreds Rain Fade Margin Moderate Strong CAPEX Low High Expansion Capability Limited Excellent Best Role Backup/smallhub Primary gateway
6. Oilfield Scenario-Based Selection ✔ Choose 4.5m Hub If: You operate a small oilfield cluster Network is mainly telemetry + basic voice Budget is tight You need rapid deployment or backup site ✔ Choose 7.3m Hub If: You manage multiple oilfields or national-scale operations You require SCADA + video + enterprise IP traffic You expect network expansion in 3–5 years You need high availability in harsh weather regions
7. Practical Engineering Insight (Important) In real VSAT design, hub size is not just about “bigger is better”.
Cost optimization High redundancy Flexible scaling strategy
8. Conclusion The choice between 4.5m vs 7.3m VSAT hub stations comes down to one key question:
Are you building a small communication node, or a regional oilfield communication backbone?
4.5m = economical, limited-scale hub 7.3m = industrial-grade, scalable gateway core For modern oilfield VSAT systems, the trend is clear: 👉 7.3m is becoming the default “serious hub station standard” for long-term operations.
In the selection between 4.5m and 7.3m satellite antennas, the key factors are link budget, service capacity, and operating environment, where stability and long-term reliability remain the top priorities.
Antesky focuses on the R&D and manufacturing of large-aperture satellite antennas, offering 4.5m, 7.3m, and other configurations to meet various VSAT and earth station requirements.
For product specifications, configuration guidance, or quotations, please feel free to contact us for more details.
Can geostationary satellites be seen from the earth ? The answer to this question was Yes. Use a fixed camera and a long time exposure.
Example image Geostationary satellites as seen from the earth. The horizontal streaks are the background stars slowly moving across the fixed camera view, over an exposure period of several hours.
Question now : Does anyone know of software that will show the location of geostationary satellites against a background of the visible night sky stars.
The two SSPAs have weatherproof NEMA 4X type enclosures and may mounted outdoors at the antenna hub to to reduce waveguide losses at 14 GHz between the SSPA and the transmit port of the antenna feed. These SSPAs have been designed for reliable, trouble-free service and were in good working order when last in service. The amplifiers incorporate a microprocessor-based monitor and control system.
This first image above shows a side view of the two block up converter / solid state power amplifiers. On the undersides, on the right, are the redundant cooling fans. The mounting brackets are visible.
The second image above shows the weatherproof white upper faces.
This document also provides outline measurements as well as measurments for the four mounting bracket bolt centres.
L-band input is via an N type coax connector and output is via 14 GHz waveguide.
There is also an explanation of the part number. SPKM14100N-7 The fourth character "M" indicates the output is 14 - 14.5 GHz. The 7th to 9th characters "100" indicate 100W output power. The final character "7" indicates that it is a block up converter with an L band IF input.
Regarding output power, these SSPA have the following specification: Saturated outut power 100W P1dB output power 85W Linear power (IMD = -25 dBc with regard to the sum of both carriers) 42.5W
If you intend to operate simultaneous multiple transmit carriers note the linear power spec.
Aligning linear polarisation with only the wanted signal being observed and measured
If you are trying to align linear polarisation and only have the wanted signal being measured it is definitely not possible to align the polarisation with sufficent accuracy by adjusting for maximum signal strength, as the maximum is very wide.
One possibility is to misalign the polarisation by a considerable amount till a significantly lower level, but accurately recordable level, is observed. Record the this level accurately and also mark the angle on the feed throat. Then repeat the process on the other side of the maximum. Then carefully rotate the feed to a final position half way between the two marked positions. At this point, for a receive only antenna you are finished. If it is transmit antenna you can now contact the network operations center (NOC) and ask for permission to transmit. They will ask you to transmit a low level CW (unmodulated) carrier and they will observe what cross-pol interference you are causing. Hopefully this will be acceptably very low but they may ask for small adjustments for you to make. If they do ask you to make manual adjustments do it under phone contact with the NOC and be very patient and be prepared to wait for the NOC to make accurate measurements, which each may take several seconds to stabilise and record.
If you have a spectrum analyser and can observe multiple carriers over say 70 - 200 MHz you can try boldly rotating the feed and watching for cross polar carrier levels (typically visible inbetween your wanted polarisation carriers), which will rapidly drop to zero as you go through the sharp cross-polar null. This is not always the case if there is litle or no traffic on the opposute polarisation.
If you have a spectrum analyser and can observe the satellite beacons then prepare a note of the status of the various beacons and their frequencies. From this you can determine what polarisation you are using and also verify the satellite identily!. For example, a satellite might transmit one circular polarisation beacon on one freqnbecy and one linear polarisation beacon on another frequency.
Never transmit until you are certain of the satellite identity, your polarisation is approximately right and you are in phone contact with the NOC for permission so they can see your signal come up in the right place. If in any doubt or loss of phone link, turn off your transmit right away.
Feed systems vary. Many types comprise a linear polarisation OMT that combines two rectangular waveguides one TX, the other RX) into a single short circular or square cross-section waveguide. Between this and the feed horn is a polariser tube which contains a row of slots, pins or similar devices. This line is set at 45 deg to the linear polaristions of the OMT. Depennding on which way (+45 deg or -45 deg) the OMT to polariser junction is set make the feed operate clockwise transmit or anticlockwise transimt and the opposite on receive.
Which circular polarisation you are set to will be confusing. Not that one way will work perfectly and the other way no at all. So if you cant find the wanted signal at all then try the opposite polarisation. Confusion is common due to the polarisation changing each time the signal is reflected (once for frond fed antennas, twice for Cassegrain of Gregorian geomentries. Documentation is often not clear about the +45 or -45 deg and scales may be marked 0 - 360 or +/-180. Don't worry, just try one way is if no good try the other. Once it works document or photograph carefully so you can repeat at other sites.
My experiences of interference in satellite communiations include:
Interference to and from nearby satellites
Interference to and from nearby satellites in the geostationary orbit. To mitigate this antennas, both transmit and receive, need to have low sidelobe levels. International agreements and bilateral intersystem coordination agreements restrict off-axis eirp limits for transmit antennas.
Interference from terrestrial sources
Interference from terrestrial sources such as nearby microwave towers and radar are examples. Also much closer serious interferers can include neon signs, hand held cell phones and walkie-talkies, even clicks / spark noise bursts from air conditioning motors. Hiding a dish using site shielding is sometimes necessary.
Sun noise
Around the spring and autumn equinoxes, as the sun daily moves across the sky it will briefly go behind the satellite. During this time (up to several minutes) high noise levels occur. The sun appears a noise source at approx 8000 deg K.
Atmospheric effects
If you attempt satellite communications with satellites at low elevation angles the signals vary in level, called scintillation. It is exactly the same phenomena as the twinkling of a star near the horizon. It is caused by layers of different moisture and temperature content in the lower atmosphere or troposphere. The layers bend the radio signals rather like ripples on a water surface cause moving patterns of sunlight on the base of pool.
Rain and melting snow cause both attenuation of the signals and also increase in noise level due to the absolute temperature of the water.
Ionospheric effect
The polarisation of radio signals is rotated by the ionosphere. The problem is greater at lower frequencies like L band (~1.5 GHz) and is reason why circular polarisation is preferred at such frequencies.
It is about how to check that the rim of the antenna is accurately flat. Aim for an accuracy approaching 1/10th of the wavelength of the frequency in use.
