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A–2
1.2
Transmitter (TX)
The transmitter frequency scheme follows the receiver design. In addition, the transmitter is capable of
transmitting two sidebands independently (ISB-operation). For example, one can transmit an SSTV
signal on LSB and a voice (phone) comment on USB for example. The transmit power is 100 or even
600 Watts with enhanced filtering:
1. The PT-8000 transmitter stage starts with a Class-A 10 W driver amplifier operating from 1.8 to
150 MHz. IMD3 is less than –50 dB at 2.5 W.
2. The 100 W power amplifier utilizes a 50 V HF-MOSFET which is actually a "Gemini" package
hence comprising two HF-MOSFETs working push-pull (SD2932). This HF-MOSFET is capable
to dissipate 500 Watts and delivering up to 300 Watts output power. The PA of the PT-8000A is
limited to 100 Watts hence presenting a signal with outstanding IMD characteristics.
3. The 600 W final amplifier includes a pair of high-efficiency (70%) SD3933 HF-MOSFETs — a
breakthrough in transmitter design.
4. The PT-8000 assures clean output thanks to innovating filtering, including the use of additional
three 70.7 MHz roofing filters in the transmitter stages.
5. A diplexer-filter guarantees optimum performance of the finals. An automatic antenna tuner
(ATU) is an integral part of the output design. In terms of power handling capability of these
components there is no difference between the 100/600 W models.
6. For VHF operation (144 MHz to148 MHz) a 13,8 V VHF-MOSFET (RD70HVF1) is used,
designed to deliver 25 watts output.
1.3
Power Supplies And Growth Potential
The HN-8000 consists of switching power supplies with full power factor correction (PFC) as demanded
by many energy suppliers. It is capable of delivering up to 1,000 W 13.8/50 V DC-power for the PT-
8000 A. The HN-8000 designed for the PT-8000 B is capable of delivering up to 2,000 watts DC power
at 13,8/100 V supply voltage. Both power supplies are rugged in design and deliver ample power for the
PT-8000 series. The DC-input power can easily monitored with the large front panel power meter.
As your operating horizons expand and new demands occur, your PT-8000 will respond:
1. The PT-8000 is the ideal platform for exploring the world above 50 MHz. Not only does it offer
outstanding 6 and 2 meter transceiver performance, the PT-8000 is designed with UHF and
microwave transverters in mind. It offers 1 Hz frequency resolution and the ability to connect
transverters to both receivers simultaneously.
2. The PT-8000 provides output taps at the first and second IFs for analysis, monitoring and
experimentation.
3. The PT-8000 firmware is easily upgraded – as described in Part D of this manual.
Part A Introduction
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