SCS PTC-IIex, Manual

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16 History
Chapter 16
16 History
Two German hams DF4KV and DL6MAA initiated the PACTOR project. As early as
1986, experiments with modified AMTOR protocols began. In tedious tests, the noise
conditions on the HF-Bands were investigated, and the best transmission parameters were
determined. Additionally, a lot of mathematical calculations were performed, the
PACTOR protocol deduced from these results.
The first PTC's were wire-wrapped on bread-boards. DL6MAA built his PTC based on a
SMD Z80 single-chip processor, while DF4KV wire-wrapped his PTC in conventional
Z80 technology.
The third station that got on the air in PACTOR was DL2FAK. His PTC was based on
DL6MAA's SMD Z80 version. DL2FAK and DL6MAA ran a lot of tests that resulted in
considerable improvements to PACTOR. In the fall of 1989 he developed a PT-link
system that facilitated access to Packet-Radio nets from PACTOR.
Since the SMD based PTC of DL6MAA was too difficult for home construction (SMD),
and DF4KV's version contained too many parts, it was decided to develop a completely
new hardware design.
DL3FCJ developed the digital section of this hardware, DL6MAA developing the
modem, and carried out software adjustments. The software was rounded out with
inclusion of an RTTY and AMTOR routine from DK4FV. DL1ZAM revised the circuit
diagram and produced the printed-circuit-board layout, and so the well known
SCS
-PTC
came about, and quickly covered the globe.
In 1993 the production of the Z80-STI peripherial chip, used in the Z80 PTC, ended. This
was then the opportunity to develop the PTCplus. Based on an MC68000 processor, the
PTCplus is the springboard to a totally new dimension in modern HF communications.
Together with the PTCplus, the development of the PTC-II was also undertaken. The
PTC-IIex project required a thorough knowledge of signal processing technology and it´s
associated programming. Much research work was necessary to develop the present
PACTOR-II modulation process. Despite all this, it was possible to astonish visitors to
the 1994 HAM-Radio convention with the first prototype PTC-II.
This manual is built up from a collection of articles by DL1ZAM, DL6MAA and
DK5FH. DL3FCJ collected the various parts together, improved and completed them, and
made them suitable for use as a manual. The manual is written using Microsoft Word and
printed on an HP Printer.
In summer of 1999 the “small brother” of the PTC-II, the PTC-IIex was ready for sale.
Being less expensive at excellent performance and the increasing need of email via HF
made the PTC-IIex to be THE standard modem for HF-email within a short time.
Summer 2001 is the time of the PTC-IIpro. Being the successor of the PTC-II, the first
PACTOR-II modem, the PTC-IIpro now establishes the new top of
SCS
’s goal to
provide the best modem-technology for data transmission via HF at all.
At the first of May 2002
SCS
introduced the new developed high speed data mode
PACTOR-III. PACTOR-III is a third generation HF protocol building on latest
developments in 2-dimensional orthogonal pulse shaping, advanced error control coding,
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