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Explains the fundamental concepts of **PSK-31** digital mode, detailing its origins from phase shift keying and how it achieves a narrow 31 Hz bandwidth. George Rothbart, KF6VSG, demonstrates the signal's behavior on an oscilloscope, illustrating the 180-degree phase shifts that define its bit stream. The resource highlights PSK-31's superior signal-to-noise ratio compared to FSK, noting its 20 dB advantage over SSB, which enables reliable cross-country contacts with QRP power levels. It also delves into the unique **vericode** character encoding, which uses variable-length bit patterns to optimize data rate by assigning shorter codes to common characters, resulting in an average of 6.5 bits per character versus 10 for ASCII. The presentation concludes with practical guidance on assembling a PSK-31 station, outlining the necessary computer hardware, sound card, stable HF transceiver, and cabling, along with methods for PTT control via a COM port.

PropNetPSK is a PSK (Phase Shift Keying) program capable of receiving multiple signals (2 - 16) at one time for the exclusive use to decode a properly formatted PropNetPSK beacon signal. If you are looking for a Keyboard to Keyboard type of program, this will not fit your bill.

The 2200-meter band (135.7-137.8 kHz) presents unique challenges for amateur radio operators due to its narrow 2.1 kHz bandwidth, low signal levels, and high noise. W1TAG explores various transmission modes suited for this demanding environment, highlighting that traditional voice modes like SSB and AM are impractical. Plain old CW serves as the baseline, demonstrating effectiveness across different modes, though signal-to-noise ratio (SNR) significantly limits practical speeds. The article notes that reducing CW speed below 5 WPM can improve copy, especially with computer-aided spectrum analysis software capable of decoding signals too weak for human ear reception. QRSS, or "CW sent slowly enough that speeds are best expressed in seconds per dot," is a key mode for LF work, with examples ranging from 3 seconds/dot to extreme 240 seconds/dot transmissions. _Argo_ by I2PHD is mentioned as a simple program for QRSS, enabling reception of signals like BRO, a Part 15 beacon, at a distance of **1100 miles**. Other modes discussed include Dual Frequency CW (DFCW), which uses frequency shifts to distinguish dots and dashes, and Binary Phase Shift Keying (BPSK), a phase modulation technique employing 0 to 180-degree phase flips. WOLF (Weak-signal Operation on Low Frequency), a specialized BPSK form by KK7KA, encodes 15-character messages into 960-bit packages, taking 96 seconds to transmit, and has demonstrated successful reception over **672 seconds** for a message from a 1-watt beacon. Further modes include PSK, FSK variations like JASON and MSK, and graphical modes such as Hellschreiber and Chirped Hell. The article concludes with a practical chart comparing the time required to send a simple message like "WD2XES FN42CH " across these diverse LF modes, offering valuable insights for operators planning contacts on the low bands.