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Maritime communication in Zaanstad

New digital VHF radio system for waterway monitoring in Zaanstad

Abiom designed and installed a fully digital marine VHF radio network for analogue communication on the Nauernasche Vaart and the Zaan in and around the municipality of Zaanstad. Abiom now monitors the network 24/7 and provides services when needed.

The cultural heritage and beautiful Dutch tradition of collecting bridge fees with a wooden clog on a fishing rod, is history. In 2022, 24/7 control centres with a regional role are the standard in marine radio communication. And that is exactly what the municipality of Zaanstad now has in place. In this region, the communication system around the bridges and lock on the Nauernasche Vaart and the Zaan was very outdated. ‘The communication structure we found there did not meet the current needs and requirements that are appropriate for such an environment. Due to the increased traffic on the waterways, the radio planning for the VHF channels was in need of an update,’ explains Jan de Groot, who designed the new system as a concept designer at system integrator Abiom. ‘The same frequency was being used in different parts of the area, which caused confusion. The coverage was also not optimal everywhere.’

Smart organisation

Abiom won the tender for the design, installation, monitoring and maintenance of the new marine VHF system. It is a project that requires not only advanced technology, but also smart organisation and reorganisation of the necessary channels. On behalf of the municipality of Zaanstad, Abiom created an RF planning and implemented the final allocation of channels in collaboration with Radiocommunications Agency Netherlands. Abiom divided the area — which runs from Krommenie to the North Sea Canal — into four segments. In consultation with Radiocommunications Agency Netherlands, each segment was then given its own channel.

Abiom supplied various shore stations, the marine radio systems along the waterways. For the VHF transmitter and receiver, Abiom selected the digital Kairos radios made by the Italian company Radio Activity, part of the renowned JVCKENWOOD Group. The radios have their own IP address, so they can be connected directly to the municipality of Zaanstad’s fibre-optic network. The digital radios are linked to the Mimer software provided by LSE, a Swedish company which Abiom has worked with for many years. De Groot: ‘We made a test setup at our office in Houten first, to ensure a good connection between the hardware and software. Then we headed to the area itself to start installing the transmitters/receivers, the antennas and the necessary software in the Port Office of the municipality of Zaanstad.’

‘There is a wealth of knowledge at Abiom.’

Albin Glaser, department head of Ports & Waterways in Zaanstad

Optimal range

Achieving a good range for waterway monitoring on a river and a canal takes a great deal of craftsmanship and calculations. In terms of coverage area, a transmitter must simultaneously transmit signals on a narrow bandwidth and across a long distance. This requires special directional antennas. The winding Zaan river posed an added challenge. A good VHF radio network also requires tuned reception sensitivity and outgoing transmission power for the transmitters and receivers, which very specifically cover certain parts of the Nauernasche Vaart and the Zaan.

Additional shore stations and antennas were installed to improve the range. De Groot: ‘We installed most of the antennas and shore stations near the objects with cameras, since that’s where infrastructure such as a fibre-optic connection is available. This enabled us to create a reliable connection.’ The connected radios are equipped with GPS for time synchronisation, so the transport over IP can take place with accurate timing. This increases the reliability of the communication and the transmission logs.

Thanks to maritime relaying, the harbour master can control radio communications around a specific bridge or lock in the area. When a ship requests passage, the harbour master responds via the semi-duplex shore station at the bridge or lock. As a result, all VHF radio users within the service area receive these radio transmissions, which provides added safety.

Five workstations

Abiom also supplied the graphical user interface (GUI/operating software) for the five workstations in the Port Office at the Julianasluis lock in Zaandam. This is the epicentre of all VHF radio communications in the area: all incoming and outgoing communication is transmitted via the radio server there. All shore stations are connected to this server via the IP network. Using Mimer voicelogging software, all conversations are also recorded on this server, so that they can be retrieved for reconstruction or analysis. In addition, the server uses a VPN connection to connect with Abiom’s Network Operations Centre (NOC) in Houten, where all alarms are monitored 24/7 and immediately forwarded to the service organisation if necessary.

Staff used to work with analogue controls in the control room, but now they have a fully digital control system. For the marine VHF radio controls, each operator has a touch screen with a clear GUI, a tabletop microphone and a foot pedal at their disposal. Operators at all workstations can communicate throughout the four segments, although in practice each operator tends to cover a specific area during a shift. During the transition from the old to the new control room system, there was also a great deal of consultation with the users, of course. De Groot: ‘This means the software is perfectly tailored to the working methods in the control room.’


The system is future-proof. De Groot: ‘Not only will it last for many years, it can also be expanded with additional functionalities. Examples include telephony, intercom/broadcasting services for the bridges and the lock and possible expansion to multiple channels.’

The project in Zaanstad is a good fit for Abiom. De Groot: ‘We don’t like to just deliver something and then walk out the door. We prefer to establish a long-term relationship with our clients in which we ensure that the technology matches the working methods, and vice-versa. For us, customised solutions are the norm. That’s how we ensure that clients can rely on us 24/7.’

Client testimonial

Albin Glaser is department head of Ports & Waterways in Zaanstad.

‘The system we were using until last year was very outdated. We also did a lot on channels 20 and 18, which are used in Amsterdam as well, and that caused static.

In short, we needed a stable, modern and reliable system. During the tendering process, we focused on quality, and that’s how we ended up choosing Abiom. They have a wealth of knowledge, and we saw this during the installation and implementation as well. Abiom also handled the new RF planning with Radiocommunications Agency Netherlands, which took a lot of work off our hands.

My team had to get used to the new VHF radio system in the beginning, of course, but now they really like it. The operators have a touch screen that helps them do their work effectively. And if there is ever a problem, I can call Abiom, and they’ll take care of it.’

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