Digital Modes - PSK
PSK - Phase Shift Keying
Phase Shift Keying is a digital modulation scheme that conveys data by
changing, or modulating, the phase of a reference signal (the carrier wave).
The simplest PSK technique is called binary phase-shift keying (BPSK).
It uses two opposite signal phases (0 and 180 degrees).
Amateur-radio operators use a special form of BPSK or QPSK known as
PSK31. In this mode, the data transmission rate is 31.25 baud (state changes
per second), and the signal bandwidth is approximately 31 Hz. The main
advantage of PSK31 is its excellent signal-to-noise ratio (S/N or SNR),
which allows communication under adverse conditions such as severe fading,
noise, or interference where other communications modes fail.
There are thousands of Amateur Radio enthusiasts using PSK all over the
world. The European PSK Club,
or EPC for short, is an informal club of amateur radio operators dedicated
to maintaining high levels of amateur radio communications on PSK modes.
| Northwest ARC is a member of the EPC. As well as
learning about and using PSK, our members can now participate in award programmes
using club equipment. |
EPC#7377 |
PSK31 was developed by English amateur radio operator Peter Martinez
(G3PLX) who introduced it to the amateur radio community in December 1998.
This new mode of transmission was enthusiastically received, and has
since quickly spread into worldwide use. Due to the efficiency of the
mode, it has become especially popular with operators whose circumstances
do not permit the erection of large antenna systems and/or the use of high
power.
PSK31 is one of
the most common and easy-to-use digital modes as a PSK31 station needs
only to consist of an SSB transceiver, an antenna, a soundcard
equipped PC and suitable software.
Because the mode is seen as such an effective means to communication
via PC, its audience has grown like wildfire in the years since its
release and lent a new tone to the on-air conduct of digital
communications.
A basic PSK31 station should consist of the following components:
HF SSB Transceiver
Soundcard-equipped PC
Antenna
PSK31 Software
(optional) Soundcard Interface
Software for PSK31 is abundant, so the choice of software packages
depends largely on personal preference, as will PC system requirements.
Some of the more popular ones are DigiPan or DM780 which is found as part
of Ham Radio Deluxe.
Frequencies used for PSK
1.838
3.580
7.035 for region 1 and 3 - 7.080 for region 2
10.142
14.070
18.100
21.080 (although most activity can be found 10 kHz lower)
24.920
28.120
If you want to know more about PSK31, further information can be found
at the following external links:
Official
PSK31 website
Technical
details - wikipedia
European PSK Club
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