Hilberling PT-8000, Operating Manual

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A–1
Part A Introduction
1 PT-8000 S
E R I E S
O
F
T
R A N S C E I V E R S
- C
H A R A C T E R I S T I C S
Hans Hilberling, DK7LG, the founder of Hilberling GmbH and a veteran Amateur Radio operator and RF
engineer specified the design requirements of his “dream-transceiver”:
1. It must include a single high-quality transmitter with two independent receivers covering the
entire HF and VHF spectrum.
2. VHF operation must be an integral part of the design, not an afterthought. VHF performance
must match HF.
3. Its operational frequency range must be easily expandable through the use of transverters.
4. It must include independent sideband (ISB) capability.
5. The design must incorporate both analogue and digital signal processing, using the best of both
technologies.
6. It must provide high output power on HF through the use of modern, efficient HF-MOSFETs at
50 V (PT-8000A) and 100 V (PT-8000B) drain voltage .
The result is the PT-8000 series of HF/VHF-Transceivers featuring cutting-edge design!
1.1 Receiver (RX)
Each of the two identical receivers are double super-heterodyne Rx with 70.7 MHz 1
st
intermediate
frequency (IF) and 10.7 MHz 2
nd
IF. The PT-8000 incorporates high quality, state-of-the-art receiver
design, including:
1. An automatically tuned preselector which is a series tuned circuit from 1.8 to 30 MHz. The main
inductance is based on a T-200 toroid. Research has shown that the IMD characteristics
correlate with the mass of the material and the transformation ratio used. The IP3 of this
preselector is outst50dBm. The series circuit is tuned through software by 5 inductor
taps (5 bit) and an 8-bit capacitor set. A noise generator is used to tune and store all settings in a
table. In order to enhance the filter characteristics the circuit is operating at approximately 3
ohms – there are down and up transformers at the input and output.
2. Precision-matched first and second mixers with third intercept points at +40 dBm. The mixers are
designed specifically for Hilberling by Synergy Microwave, a respected name in the industry.
3. Three 6-pole roofing filters at 2.7 kHz, 6 kHz and 12 kHz for outstanding inband IMD and BDR
performance.
4. Six hybrid amplifiers from LF to VHF with third intercept points at +50 dBm
5. The first local oscillator is designed with quadruple microwave VCOs which offer excellent phase
noise characteristics: -130 dBc/Hz at 10 kHz and –145 dBc/Hz at 50 kHz. The first local oscillator
design features microwave VCOs designed specifically for Hilberling. It includes a 0.05 ppm
reference oscillator with organic DDS. Phase noise suppression is enhanced by means of 300 Hz
crystal filtering.
6. The PT-8000 uses ultra-sharp 10.7 MHz IF filtering. The key to the receiver’s performance is its
seven 16-pole ladder filters working in combination with DSP filters in the 10.7 MHz second IFs
of each receiver. The filter shape factor is an excellent 1.3 at 2.4 kHz. The same high-quality
filters are used in the transmitter stages as well. 17 of these filters are used in the PT-8000.