When to buy a new antenna?
What is the life cycle for an antenna?
The life cycle for a VSAT antenna typically spans up to 10/15 years. As for any other piece of equipment the older it gets the higher probability it will have to fail. When a particular antenna model reaches its end-of-life, repairs become increasingly difficult and expensive. Also, by the time an antenna gets to its end-of-life, there will be new models released onto the market which will most likely perform better and have enhanced functionalities.
Regular health checks and preventive maintenances will help extending the lifetime of your system keeping it in good conditions.
When to buy a new antenna?
We see various possible scenarios:
- When the antenna is old or end-of-life. When an antenna is end-of-life, there will be less and less spare parts available, no software updates and the manufacturer might also stop supporting these systems. When this happens, then it´s usually time to consider changing the antenna.
- If the bandwidth needs of the boat increase. I.e. during the pandemic the demand for upstream has grown considerably mainly due to the increase of teleconferencing both for work and educational purposes. For this reason, many of our customers considered upgrading their hardware with bigger antennas and / or Block Up Converters (BUCs)
- If the boat changes its scope of work including a wider cruising area. For example, a Med based Yacht might consider an antenna upgrade before leaving for a trip in South America or Antarctica, then a bigger antenna would be advisable.
- Upgrading to the latest antenna versions supporting multi-band frequencies (e.g., Ku, Ka, C) for future proofing, or in case the boat needs to sail to areas covered only by a specific band.
- Upgrading to dual antenna system, very often one antenna might have big blockage angles as part of the sky is obstructed by the mast or funnel. In this situation, a second antenna will increase service availability.
- A mention about Low Earth Ordit (LEO): new antennas that are future proof, but note that there are many uncertainties still about how LEO services will be operated.
When to upgrade an existing antenna?
Did you know you can change the Block Up Converter (BUC) without changing the antenna?
A BUC can be replaced if broken using the same model but also upgraded with a more powerful one usually using an adapting kit.
Please be aware that not all BUCs can be installed on all antennas or used for any service. Before purchasing a new BUC always ask the manufacturer or supplier for the compatibility list or call your VSAT provider for advice; we will be happy to assist you with this.
A powerful BUC gives you the potential to reach more upstream bandwidth, but this is not automatic, you will still need to purchase the extra capacity. In other words, a bigger BUC will not automatically increase your upstream, but will make the system more reliable and resilient to bad weather, increasing the overall stability.
In summary, a bigger BUC means increased availability and potentially better speed.
Which BUC should I choose for my antenna?
This is not an easy question as it depends on the dish size, location and required bandwidth. As a guideline we can say that for a typical 1mt antenna in Mediterranean and Caribbean 8-16W are usually enough for most applications.
Moving outside of these areas a larger BUC would be recommended.
Where to place an antenna
Reducing blockage
Antenna positioning is crucial. There are many components that play a part. You can find the positioning requirements in the VSAT manual. Here is a summary of our recommendations:
- Safety. Safe access for technicians and also avoid positioning the antenna too close to crew and guest areas due to electromagnetic radiation.
- Out of radar beams. The antenna has to fall outside of any radar beams to avoid interference/ signal loss or possible damage to the antenna.
- Position the antenna as high as possible and as far as possible from the structures that might create blockage, there by minimizing the blockage angles.
- Yacht aesthetics. In yachting, aesthetics is everything and also to be considered when positioning the antenna.
- Minimize cable length. We all know that cables introduce signal loss, therefore the shorter the cable length the lower the attenuation.
- Positioning of dual antennas is very important, the positioning should be symmetrical with regards to the blocking structure. The same concept applies to a dual TRVO system. In addition, if a dual TVRO and dual VSAT system co-exist, we recommend that the they are installed crossed and symmetrical. For example, VSAT 1 AFT port side, VSAT 2 FORE starboard side, TVRO 1 at FORE port side and TVRO 2 at AFT starboard
Dual antenna is better than single for many reasons
Anything higher than the antenna such as masts, funnels, TV reception only (TVRO), cranes and other antennas can block the VSAT signal to the satellite causing service interruptions.
Although desirable, it isn’t always practical to mount the satellite antenna at the highest position. Sometimes usually, the only solution to avoid blockages is to install a second VSAT antenna.
This simple dual antenna configuration ensures your vessel has a satellite connection even when there are obstructions in the way. Having a dual antenna setup has another advantage: you have a backup antenna in case of total failure of one of them. This can be of special interest in remote regions or future proofing your vessel in preparation for Low Earth Orbit (LEO) satellite connectivity.
Finally: if a dual antenna setup is not possible, a full spare parts kit is highly recommendable.
Index of terminology
VSAT (Very Small Aperture Terminal)
These are small Rx/Tx terminals that can be installed in scattered sites connected to a central hub thanks to a satellite. In the maritime industry, antenna dishes vary from a size of 0.6 to 2.4 meters, and are usually protected by a dome. The dishes are also constantly moving, so that they get “stabilised” with respect to the satellite being tracked.
BUC (Block Up Converter)
A BUC is part of the VSAT terminal, and specifically the main transmission component. It converts the radio signals from the lower frequency, provided by the modem, to the higher frequency needed by the satellite. Note on the importance of power: it is important to have enough power on the BUC, and the more powerful the BUC is, the more upstream speeds you will be able to reach. However, there are physical limits to how much power can be installed, as well as the need for cooling when very big BUCs are in use.
LNB (Low Noise Block)
LNB is the main reception component, which receives high frequencies from the satellite and is responsible for down converting it for the modem. Today’s LNBs are compatible with multiple frequencies (multiband, quadband etc..). This is important for compatibility with any footprints.
Co-Pol or X-pol
There are 2 main polarisations in Ku-band VSAT. Most antennas sold today offer both, and it is important to note that there is usually a mix of both in any service provider’s footprints. Older antennas are often just X-Pol, and this can be limiting.
Dish Size (Low Noise Block)
When dimensioning a VSAT system it is important to understand that the gain of an antenna is proportional to the area of the dish (both Tx and Rx), so the bigger the dish the higher the gain. To give you an idea: compared to a typical 1m dish, an 80cm antenna only has 64% of the area while a 120cm dish has 143% of the area of a 1m dish:
On the receiving path a higher gain will help capture the signal coming from the satellite resulting in a more robust and efficient service.
On the transmitting path a higher gain will help focus the power coming from the BUC towards the satellite resulting in a more stable and bandwidth capable service.
In other words: Bigger is Better!
For more information please contact your account manager or send us an email: sales@omniaccess.com
