Page Comparison

Antenna system design

Installing / offering advice on installing on-vessel antenna systems to increase UHF coverage is a specialist field.

You have three main options:

1. Passive antenna system - suitable for smaller vessels with one or two blackspots

2. Repeater(s) with traditional antenna(s) - suitable for medium size vessels that cannot be covered by a passive antenna system

3. Repeater(s) with radiating cable(s) - suitable for larger vessels that cannot be covered by a traditional antenna system

As you might expect cost & complexity increases with each system. Radiating cables have another advantage in as much as it may be possible to also use them to provide WiFi coverage throughout the vessel.

Some experience in installing such systems is invaluable.

Option 1 requires manual testing of coverage of the completed, and fully loaded, vessel (so is not ideal for new builds). Entel can supply passive antenna components with a basic guide for your engineers to complete. Entel are not however able to assist in its testing or installation.

Options 2 & 3 may be able to be modelled in software to give you a good idea of their feasibility / design prior to installation (better suited to new builds). Entel may be able to recommend a specialist antenna system company to assist you.

For options 2 & 3 how many repeaters will I need?

Assuming a single antenna system you will need:

• 1 repeater per Analogue channel

• 1 repeater per two DMR Digital channels

You may of course have simplex channels in your UHF radios (for short range communications) these do not count towards the repeater channels.

If your vessel has multiple, separate, antenna systems please provide full details and we will advise.

Antenna systems compared:

Passive antenna systems

Linked Gateways (P1 / SIP)

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Advantages:

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Disadvantages:

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UHF

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·         Will only work where there is no overlap of coverage e.g. just between Bridge and Engine room.

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·         No limitation on distance between Gateways

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·         Requires Server so overall cost compared to a repeater system to be considered

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·         No limitation on the number of Gateways (as long as no overlap of coverage)

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·         Will require separate channel to one used in other areas and needs portable radio operator to manually change channel.

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·         Connects to existing WiFi or Ethernet networks (low installation complexity / cost)

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·         Cannot be installed in intrinsically safe areas

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·         Provides a single channel per Gateway set

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UHF Repeaters

 WiFi Radios