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Military VHF/ UHF Tactical Communication Systems
NEW PRODUCT LAUNCHED!
Linwave has recently launched a new 20 Watt multi-band amplifier covering 30-512MHz. The Linwave LW10-110259 is an ultra compact combined multiband integrated transmit booster amplifier and high quality receive LNA with fast DAMA compatible Tx/ Rx switching and automatic bypass upon power failure. Designed to work seamlessly with any tactical half duplex radio or radio repeater with a minimum transmit power of 0.5 watts, the unit can be configured to work with AM, FM and all types of digital modulation. Please see our datasheet linked below for more information:
Linwave staff are highly experienced in the implementation of tactical communication systems, from large Tacsat hubs through forward tactical HQ equipment to front line systems. Linwave is rapidly becoming recognized as a specialist in this important technical area and is well positioned to provide timely, performant, rugged, reliable and economical solutions for all requirements.
By definition, tactical communication systems often have to be used in difficult operational situations, with small, low gain antennas to provide essential communications beyond the front line. The transmit powers and receive sensitivities of tactical radios are not always adequate to provide reliable communications to these low gain tactical antennas which may be situated under tree cover, or to omni-directional antennas which may be used while on the move at speed over rough terrain or on water.
Practical conditions on the ground often force the separation of radio from antenna. With a copper interconnect, valuable transmit power is rapidly lost, even with a heavy grade coaxial cable which is totally impractical in theatre. Linwave have extensive experience in the design of application specific VHF/ UHF systems for military terrestrial line of sight and tacsat applications which remove this limitation. These include fully integrated two box fibre optic antenna remoting systems and copper boosters, all designed to work with a wide range of tactical radios to implement key applications, including the latest high data rate fast DAMA protocols specified for international network wide applications. Related issues such as co-site interference are routinely addressed by the use of high isolation switches and transmit reject filters.
As a result of this work, a range of proprietary modules exists together with an in depth understanding of the system level requirements of tactical communications. This allows Linwave to combine existing module designs quickly and efficiently to provide optimised solutions. Together with extensive experience in the packaging of equipment for harsh environments, this results in products which are exceptionally rugged, reliable and fit for purpose.
For further information please contact us at enquiries(at)linwave.co.uk.
VHF/UHF Modules
- Transmit bandpass filter banks covering the frequency range 30 to 512 MHz.
Tacsat transmit reject filters must provide excellent rejection out of band. This requirement is driven by the proximity of the Tacsat receive band which stops just 20 MHz below the transmit band. As well as rejecting any stray transmit energy from the local power amplifier, the filter must reject co-site interference up to a level of 5 watts at the antenna output.
- Tacsat transmit reject filters:
Tacsat transmit bandpass filter banks are predominantly used to remove harmonics generated by non-linearities in the transmit amplifier chain after the tactical radio.
The number of filters used to cover the band 30 to 512 MHz varies with application, but is typically from three to five. Rejection requirements also vary with application, but second harmonic is typically specified as -40 dBc.
Because of the stringent requirements dictated by the proximity of the Tacsat receive band, a higher order Tacsat specific transmit bandpass filter is usually specified. In all cases, the insertion loss for each transmit bandpass filter is kept as low as practically possible to minimize energy loss and heating which can be significant.
- High power fast PIN switches to 100 watts.
This range of Tx/ Rx switches covers the band 30 to 512 MHz. Power rating is continuous. Loss is minimized to maximize power at the antenna and minimize thermal dissipation from the switch.
- Ultra low noise LNAs.
The receive signals encountered in practical Tacsat receive systems can be as low as -120 dBm. This is actually below the specified range of some tactical receivers. High gain, low noise amplification of these tiny signals is essential if communications are to be robust.
Linwave has extensive experience in the design of LNAs at all frequencies to 40 GHz. This experience has allowed them to develop extremely high performance VHF/ UHF LNAs for tactical communications applications.
LNAs are also critical in fibre optic based antenna remoting systems, where it is essential to bring the receive signal into the dynamic range of the fibre optic transceivers which form an essential part of the system.
- Power Amplifiers:
- High power narrowband, 270 to 320 MHz, Tacsat amplifiers to 100 Watts
- High power wideband, 30 to 550 MHz amplifiers to 50 Watts.
To date, power amplifiers have been implemented using LDMOS. New technologies are being evaluated for the latest designs, including Gallium Nitride and Silicon Carbide. These highly efficient technologies will allow lower power systems to be developed. This is frequently a key requirement, especially where power is limited.
- Control Systems
A key strength of Linwave is the ability to develop unique solutions which embody both advanced RF design and software based control systems. In the more complex tactical communication systems, the control systems provide real time sequencing, monitoring and, critically, the ability to implement complex power saving strategies which minimise battery drain and thermal dissipation. Standard hardware designs and a comprehensive suite of software routines allow the rapid development of application specific solutions. An added benefit is the ability of the operator to monitor the status of the equipment through standard interfaces such as web browser and snmp.