LINEAR AMPLIFIERS MADE IN THE UK

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Linear Amp Gemini HF-1K 472kHz-50MHz 1kW Solid State Linear Amplifier

1kW Output
High Spectral Purity
460KHz* to 50MHz All Bands
Touch Screen Full Colour LCD Display
Full Diode Switched QSK
Fully automatic Band switching
Network and remote capability

Multiple antenna outputs
0dBm SMA predistortion output
Advanced Cooling
DUAL NXP BLF188XR LDMOS with Full Protection
100-260V 50-60Hz power input
Weight 19Kg

* With external low pass filter (not supplied)

The Gemini HF-1K is a solid-state 1kW 1.8MHz – 50MHz power amplifier with additional capability at 472kHz. It uses a PAIR of BLF188XR dual-LDMOS power devices for reliability and high spectral purity and has an internal highly reliable low-noise switching power supply, in order to reduce the overall weight. The thermal design is very conservative with a large heatsink, and OFHC heatspreader. This, assisted by several fans and a sophisticated thermal management system, allowing the channel temperature of the LDMOS device to remain within limits which should ensure extended life, even with with heavy usage and yet quiet in operaiton with fans only operating when required.

A major objective of the RF design has been to significantly exceed the spurious signal generation requirements of the international approvals standard (ETS 300 783 pts 1 and 2) for amateur radio equipment. To this end the Gemini HF-1K has more extensive filtering than is usual in HF PAs.

While LDMOS power FETs are amongst the most rugged RF power amplifier devices currently available, they are sensitive to RF overdrive. The Gemini HF-1K has both extensive monitoring to minimise the risk of damage by overdrive and a conservatively designed input circuit.

The Gemini HF kW employs full touch-screen control using a 480 x 272 pixel 108mm mm full colour TFT display. A wide range of monitoring functions can be displayed, including power output, PA drain current, VSWR and heatsink temperature.

As with other Linear Amp UK designs, there is no provision for ALC, as this is a major cause of bad signals.

Band selection is fully automatic. The presence of valid in-band signals is detected and will initiate switching automatically to that band.

A high-speed, very low distortion, solid-state switching circuit allows very fast (>50wpm) full break-in operation.

A single input and three selectable antenna output connectors are provided. The latter can be preset on a band by band basis.

A 0dBm (basis 100W output) SMA feedback output is provided to allow connection to transmitters with predistortion linearisation capabilities or for other monitoring functions.

The Gemini HF-1K has full network capability allowing remote operation and firmware upgrades. See links below for the remote software.

The amplifier is built in a very robust all aluminium case. A modular assembly approach has been adopted with non-RF and high current DC interconnects being distributed as a single bus.

Operating frequencies: 460 – 479kHz*

1.8 – 2.0MHz

3.5 – 4MHz

5.0 – 5.5MHz

7.0 – 7.3MHz

10.1 – 10.2MHz

14.0 – 14.4MHz

18.0 – 18.2MHz

21.0 - 21.5MHz

24.8 – 25.0MHz

28.0 – 29.7MHz

50.0 – 54.0MHz