Search results

Premium quality QSL cards, with samples, preview and on-line order

Catalogs a diverse array of Software Defined Radio (SDR) projects and realizations, systematically classified by their sampling methodologies and underlying hardware architectures. The resource delineates projects into categories such as those utilizing soundcard sampling of traditional transceiver audio outputs (Type Ia), mono soundcard sampling of intermediate frequencies (Type R1x-x-xx), stereo soundcard sampling of I/Q IFs (Type Q1x-x-xx), dedicated stereo audio ADC sampling of I/Q IFs (Type Q2x-x-xx), direct antenna RF signal sampling with off-the-shelf acquisition boards (Type R3x-x-xx), dedicated RF ADC sampling of analog IFs (Type R2x-x-xx), dedicated RF ADC sampling of direct antenna RF signals with ASIC-based processing (Type R4x-A-xx), FPGA-based processing (Type R4x-F-xx), and specialized IF chipsets combining ADC and DDC functions (Type Dxx-S-xx). Each entry provides a brief description, often including pricing, availability of source code, and specific hardware components like ADCs, DACs, DDS, and FPGAs. The compilation presents various practical applications, from PSK31 and Packet radio implementations to adaptations of the DRM standard for amateur radio bandwidths, such as Hamdream and WinDRM. It features specific hardware designs like the SoftRock-40 for the 40-meter band, the Firefly SDR for 30m and 40m, and more complex systems like the Quicksilver QS1R, which employs a 16-bit 130 Msamples/s ADC and an Altera Cyclone III FPGA. The resource also lists sample processing software, RF front-end designs, and academic/commercial SDR initiatives, offering insights into different approaches for I/Q conversion and digital signal processing in SDR systems.

QSL cards by Kamko, samples, order form.

PA3FWM's software defined radio (SDR) page documents his extensive hardware and software development efforts between 2004 and 2009. Initial experiments utilized a direct conversion receiver with 90-degree phase difference, feeding a PC soundcard at 48 kHz sample rate, covering 24 kHz of spectrum around a 7080.5 kHz local oscillator. This setup, similar to AC50G's QEX 2002 article, allowed for basic I/Q signal processing to distinguish signals above and below the LO frequency. Limitations included fixed crystal frequencies, 16-bit dynamic range, and narrow bandwidth. Subsequent hardware iterations aimed for enhanced performance, incorporating external 24-bit ADCs with 192 kHz sample rates, connected via 10 Mbit/s Ethernet. A **MC145170-based PLL** and programmable octave divider provided a 58 kHz to 30 MHz tuning range. The **Tayloe mixer** was employed, with differential outputs feeding a PCM1804 ADC. An ATmega32 microcontroller handled serial data conversion to Ethernet frames, though without CRC calculation due to processing constraints. Later designs integrated AD7760 2.5 Msamples/second ADCs and a Xilinx Spartan-3 FPGA, enabling direct reception of 0-1 MHz spectrum and eventually 2.5 MHz bandwidth across the shortwave spectrum. Software was refactored to use an initial 8192 non-windowed FFT for efficient high-bandwidth processing. The project culminated in a two-way QSO on 21 MHz using the developed hardware and software, demonstrating transmit capabilities with a D/A converter. The system exhibited a 2.5 MHz wide spectrum display and a zoomed 19 kHz display, capturing signals like ionospheric chirp sounders and RTTY contest activity. Challenges included noise leakage from digital circuitry and cooling for high-power dissipation components.

RSCW demonstrates a Linux/Unix command-line utility engineered for **Morse code** decoding via a computer's sound card. It specifically targets the extraction of weak CW signals from noise, operating on 8-bit, 8000 samples/second audio input, typically from `/dev/dsp`. The program outputs decoded characters to `stdout`, supporting user-specified speeds in words per minute (WPM) and carrier frequencies. While effective for machine-sent signals, it exhibits a 2-second decoding lag and requires manual speed input, making it less suitable for general-purpose, real-time contest operation. The resource details the program's components, including `rscw` (the main decoder), `rscwx` (an X11 graphical auxiliary for spectrum and internal signal visualization), `rs12tlmdec` (a specialized decoder for RS-12 amateur radio satellite telemetry), and `noisycw` (a utility for generating noisy Morse signals for testing). Installation instructions involve downloading a `.tgz` file, compiling with `Make`, and requiring the FFTW library (and GTK 2.0 for `rscwx`). Performance is illustrated with a .wav file example of a 12 WPM, 800 Hz CW signal at 12 dB Eb/N0, showcasing RSCW's near-error-free decoding of a test message. The site provides command-line examples utilizing `sox` for audio conversion and `noisycw` for signal generation, inviting comparisons with other decoding software and human operators, particularly for weak signal conditions.

ON6MU optimized 6/9 element vhf yagui antenna with antenna schematic plan and pictures of homebrewed samples.

Sound samples of the transmission modes recorded at 11025 samples per second, mono and the message in all of the samples is the same: "the quick brown fox jumps over the lazy dog 1234567890".

About numbers stations, and their criptic transmissions, where to listen to them and some audio recording samples by fascinating shortwaves

QSL print service online from poland with lots of printed card samples

10GHz Rainscatter audio files

Information and digital audio samples of various modem modulation types

About different baluns types. Samples and schematics for several ratios baluns in french

Description, frequencies and sound samples of most popular amateur radio digital modes by DG8FBV

Some sound samples of received signals mainly on VHF-band

Ham radio, Mir contact samples in Real audio, packet and some links

G0KYA MMANA-GAL presentation and samples

A very informative review of the Icom IC-7300 direct RF sampling transceiver, including audio samples, recordings and a comparison vs the Elecraft KX3

This page has a collection of audio samples from unusual HF propagation phenomena, from round-the-world propagation to moonbounced signals , and to ducted transmission.

Operating the UoSAT-2 (OSCAR-11) satellite, launched in 1984, presents unique challenges due to its age and current eclipse schedule. This resource provides a historical archive of news, telemetry data, and specialized software for decoding its 145.826 MHz FM beacon. It includes tools like _CTERM_ for terminal emulation and capture, and U2TM for processing ASCII telemetry, enabling hams to analyze the satellite's health and performance. The site also offers audio samples of the beacon and S-band signals, along with details on hardware and software decoders. Reception reports are actively solicited for the satellite's intermittent transmissions, which occur for less than an orbit every 21 days during its eclipse period. The site details how to process raw telemetry data, including instructions for skipping initial frames to improve decoding accuracy with U2TM. It also provides software like SATILL for predicting solar eclipses and tools for determining the satellite's spin period from magnetometer or solar array telemetry, offering insights into its operational status despite its advanced age.

Definition and samples of Twin Lead Cables at wikipedia

Samples and documentation on RDF setups

All about RTTY, including audio samples, rtty software, video exaples and rtty related links

This page contains links to a variety of data signals that have been specially recorded. Each file contains a standard test message (the quick brown fox jumped over the lazy dog) repeated twice. The files can help you learn the characteristic sound of various data modes but they can also be used to make sure your decoder is working.

A large collection of morse keys classified by country with samples from all over the world

Examining the demographic shifts within amateur radio, particularly concerning **radiosport** participation, this resource analyzes survey data from the National Contest Journal (NCJ) and two regional ARRL surveys. It focuses on the relationship between age and engagement in contesting, presenting findings that suggest older amateur radio operators tend to participate in more contests annually. The author, a spatial demographer, details the methodology, including data consolidation, georeferencing, and statistical analysis performed in collaboration with Dr. Scott Wright K0MD, covering ARRL November Sweepstakes participants from 2000 to 2020. The analysis also addresses the limitations inherent in using voluntary response samples rather than random samples, which may influence the generalizability of the results. Furthermore, the resource investigates the preferred sources of contest information among different age groups, noting that older contesters frequently rely on traditional publications like the NCJ, while younger participants show a preference for online platforms. This demographic review provides insights into the evolving landscape of **amateur radio contesting** and the generational differences in information consumption.