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SWISS-PTC-2A
HF-Radio Modem

Swiss PTC-2A
Send e-mail and data over inexpensive HF-Radio links.

Highlights
  • Extremely reliable data transfer over HF-radio
  • Works with a large variety of HF radios
  • State-of-the-art DSP design
  • Adaptive modulation, interleaving, convolutional coding
  • Fast data transfer (outperforms most other HF-Modems under typical HF propagation conditions)
Description
  • The SWISS PTC-2A is the enhanced follow-on model for the very successful SWISS PTC-II. It is a state-of-the-art DSP based HF-modem designed for professional applications. The SWISS PTC-2A connects to PC-compatible laptop or desktop computers. The modem uses advanced modulation and coding methods resulting in extremely reliable data transfer even during poor HF-propagation conditions. Experience of our customers has shown, that the SWISS PTC-2A outperforms most other HF-modems under typical HF-propagation conditions. The SWISS PTC-2A modem is still transferring error-free data when other modems give up.
  • Due to the advanced frequency tracking capabilities, the SWISS PTC-2A can be connected to a large variety of HF-radios.
  • The proprietary, customer dedicated Non-Public code protects you not only against eaves-dropping but prevents unwanted pactor stations from linking up to stations of your own network.
  • The SWISS PTC-2A is the choice for efficient and reliable transmission of e-mail and data over HF-Radio links.
  • The SWISS PTC-2A modem uses extremely robust modulation methods, convolutional coding and interleaving. This allows data communications even over HF-channels with very poor propagation conditions.
  • The SWISS PTC-2A modem can be connected to a large variety of HF radios.
  • The SWISS PTC-2A modem is available in the narrow-bandwidth (450Hz) Level-2 version, as well as in the “voice-channel-bandwidth” (2.2kHz) Level-3 version. Level-2 versions can be upgraded in the field by simply entering the required L-3 license code, obtainable from your supplier.
Available messaging software
  • WaveMail E-mail software for Swiss-PTC, Packet Radio, Inmarsat phones, Thuraya, Iridium and standard telephone modems

Specifications
Data throughput Level-2 mode:
589 bit/s net usable data rate ( ~1000 bit/s with compression for typical plain text).

Level-3-mode:
Up to 2400 bit/s net usable data rate ( ~4000 bit/s with compression for typical plain text).

Data throughput depends on propagation conditions.
Under typical HF propagation conditions, experience has shown, that the SWISS- PTC II is very often faster than so called '9600 bits/sec modems'
Required S/N ratio Maintains reliable communication down to a S/N ratio of -18dB (@ B = 4kHz).
Required bandwidth Level-2 mode: 450 Hz (at -50dB)
Level-3 mode: 2200 Hz (at -40dB)
Modulation Adaptive 2 to 18 tones with adaptive DBPSK/DQPSK. Crest factor (1.9 to 5.7) optimised for the applicable modulation mode.
Channel coding Convolutional code (k-7) combined with full frame interleaving, Viterbi decoding with soft decision. Code rate adapted to applicable mode, between 1/2 and 8/9.
Compression Huffman or Pseudo-Markow plus run-length encoding, selfadaptive (optimizing)
Protocol and adaptivity Advanced half-duplex hybrid ARQ with memory. The modem parameters (code rate, number of DPSK levels etc.) continuously adapt to the varying link conditions
Frequency tracking Initial offset: up to +/- 80Hz Drift: up to 10Hz/min
Compatibility Fully compatible to SWISS-PTC-plus and SWISS-PTC-II systems with automatic switching - Public/Non- Public same as PTC-plus and PTC-II
Selective call 3 to 8-digits alphanumeric addressing
Front panel displays Alpha-numeric display, Tuning LED-bar, Connect, Sending, Error, Request LEDs
Rear panel connectors Radio port, Data port, Control port & Power switch
RX audio input RX audio input, 10mVpp to 2Vpp (balanced 600Ohm / unbalanced 47kOhm)
TX audio level Software adjustable between +5dBm and -35dBm (balanced/unbalanced)
Radio port Sub-D-15M providing balanced and unbalanced TX and RX audio, PTT (open collector), Scan-Stop, GND, +DC supply input and 3 spare pins
Serial interface (data port) Sub-D-9F connector, 2400 - 115'200 bit/s
Supply power +9VDC to 20VDC (current at 13,5VDC = 225 mA)
Dimensions Aluminium extrusion cabinet 210 * 160 * 35mm / 600g