Maximum availability and minimum costs

The revolutionary liquid-cooled high-power HF transmitters provide maximum availability with minimum operational costs

Off to new shores

The new reality for ship to shore communications

High frequency (HF) beyond line of sight (BLOS) communications are enjoying a renaissance, being one of the few technologies that can reliably provide connectivity between any two points on the planet. Here, ship to shore communications are designed to help naval vessels maintain reliable connectivity while offshore, enabling them to access real-time data and voice communications when out of range from costal systems.

Redefining the future of HF wideband communications with liquid cooling technology by Rohde & Schwarz

The revolutionary R&S®SK4105 and R&S®SK4110 HF high-power transmitters with 5 kW and 10 kW output power and HF wideband capability from Rohde & Schwarz meet the requirements for advanced long-range BLOS communications with very high data rates and maximum reliability. An innovative cooling concept minimizes operating costs and makes the transmitter a future-proof investment.

HF high power transmitter application video
Introducing the new liquid-cooled HF high-power transmitter

Features and benefits


The R&S®SK4105 and R&S®SK4110 HF high-power transmitters feature longer service life and lower failure rates by minimizing thermal load on all transmitter components, thanks to self-sufficient liquid cooling. There is no single point of failure, as each transmitter has its own self-sufficient cooling system and the internal electronics are prevented from being exposed to harsh environmental conditions, e.g. damp, salty air.

The transmitters feature a sustainable carbon-footprint. R&S®SK4105 and R&S®SK4110 feature critical module redundancy, i.e. uninterruptable transmission and operation in case of power supply failure or HF output stage failure. Replacements are schedulable at regular maintenance.

Further features include remote monitoring and configuration alongside initial error analysis and optional Uninterruptible Power Supply (UPS) for minimum downtime, i.e. the transmitter will not shut off even after power failure of entire station or excessive voltage fluctuations.

Rohde & Schwarz has proven the reliability of liquid cooling in TV broadcasting operations for 25 years.

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Total cost of ownership

The R&S®SK4105 and R&S®SK4110 HF high-power transmitters feature reduced capital expenditures (CAPEX) and operational expenses (OPEX).

Thanks to the usage of liquid cooling, instead of forced air cooling, internal electronics are not exposed to harsh environmental conditions, and the heat loss from the transmitter is contained in the liquid and can be reused. These benefits result in reduced OPEX.

Additionally, there are no replacement transmitters required to be run in standby mode, due to increased reliability, which results in reduced CAPEX. In comparison to forced air cooling in general, there is less maintenance and there are fewer mechanical components as well as fewer expendable parts, e.g. no filter for drying and desalination and the ambient air, which results in reduced OPEX, too.

Further reduced CAPEX benefits include the fact that selected replacement modules can be used in both systems; and there is no additional system procurement required to generate compressed, dried and desalinated air. Further reduced OPEX benefits include no additional maintenance and electricity consumption.

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Future proof investment

The R&S®SK4105 and R&S®SK4110 HF high-power transmitters are a future proof investment, as their components are software defined, i.e. new functions or waveforms can be retrofit easily; they support HF wideband up to 48 kHz (MIL-STD-188-110D and MIL-STD-188-141D) and Link22 (in line with MIL-STD-188-203-1A) and BRE1TA (BRE2TA ready); and are designed for bandwidths of up to 200 kHz, with the exception of the current exciter.

Furthermore, the R&S®Series4100 radio, which is part of the transmitter, is modular, i.e. HW modules can be retrofit, if necessary.

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Compact, silent and individually adaptable

The R&S®SK4105 and R&S®SK4110 HF high-power transmitters are compact, silent and individually adaptable. They feature a small footprint at just 1x19inch, a reduced noise level and a flexible liquid cooling system and customizable, self-cleaning liquid heat exchanger.

The further feature automatically adjustable speed of VANs according to the situation (speed and thus power consumption reduceable). Rohde & Schwarz has proven the reliability of liquid cooling in TV broadcasting operations for 25 years.

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Tech Talks with Robert Träger

Dive deeper into the technical details of our new HF high power transmitter with the HF communications expert Robert Träger. In each Tech Talk a specific topic will be covered and discussed.

Your challenges:

The establishment of secure beyond line of sight (BLOS) communications for shore stations at anytime, anywhere, with uncompromising reliability, maximum data throughput and minimal operational costs.

Consideration of an alternative to satellite communications (SATCOM), with similar intercontinental ranges, but without needing complex and expensive SATCOM infrastructure and the cost of leasing bandwidth. The need of a back-up for when SATCOM are not available, e.g. polar regions and regions that are “terrain-challenged.”:

  • Complement to SATCOM: reduction of running SATCOM costs (operating expenses - OPEX)
  • Alternative to SATCOM: no high investment for SATCOM infrastructure, meaning massive reduction of capital expenditures (CAPEX)
  • Robustness and security of HF leads to being less susceptible to JAMMING, SPOOFING and no danger of space-debris
  • Complete coverage of the earth's surface – reaching vessels anytime and anywhere at sea

A future-proof investment in reliable products and technologies due to the need of:

  • "Renewal" of the HF backbone infrastructure; or
  • "Renewal" of the SSSB infrastructure, or
  • Upgrade from BRASS to BRE1TA, already preparing for BRE2TA

Our solution:

HF wideband capable and state-of-the-art HF high-power transmitter with innovative liquid cooling technology implemented in the amplifier unit in order to absorb any heat generated directly at the source and to conduct it out of the rack. Decades of experience with liquid cooling in the broadcast and media market and the integration of the long-established Series4100 HF radio give way for this innovation and revolution in HF communications for shore stations.

The wideband capability and unprecedented performance in the range of 5-10 kW enables high performance HF data rates (in line with MIL-STD-188-110D) from:

  • up to 120 kbps when using groundwave under real conditions
  • up to 75 kbps when using skywave under real conditions
  • as well as robust and secure data transmission by using countless standardized and interoperable waveforms (TRANSEC, COMSEC)

The high-power liquid-cooled HF transmitter has been designed and developed with a constant focus on minimizing total cost of ownership for our customers and maximizing system availability:

  • No single point of failure in transmitter stations, due to its own closed liquid-based cooling system
  • Error rate minimization and thus transmitter downtime through an optimized cooling concept with no effect of "harsh" environments
  • Reduction of maintenance effort (effect of "harsh" environments only on heat exchanger designed for this purpose)
  • Reusability of waste heat, e.g. to heat offices in the building reducing the carbon-footprint
  • Simplification of installation of cooling system with 20mm hose instead of large customized air ducts
  • Innovative integrated redundancy concept - for continued operation in the event of faults

Liquid cooling

Learn more about the liquid cooling technology of the HF high-power transmitters for Ship-to-Shore communications from Rohde & Schwarz.

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HF communications

Learn more about why HF systems are seen as a reliable alternative to SATCOM, the national HF backbone, and Ship-Shore-Ship Buffer (SSSB).

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Learn more about the unmatched reliability of the HF high-power transmitters for Ship-to-Shore communications from Rohde & Schwarz.

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Total cost of ownership

Learn more about total cost of ownership of the HF high-power transmitters for Ship-to-Shore communications from Rohde & Schwarz.

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