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A group for the purpose of buying-selling-trading SW receivers and scanners only. Free and mainly for individuals.

The RadioFrequency Program is a professional Software dedicated to all HAM, SWL and Radio Listeners. Freeware. Included is a Text-CSV dBase Converter. Connection to the ICOM R8500 Receiver. Special Scanning Feature. Special Search Feature x large dBase.

80 metre superhet SSB receiver project

A simple free running oscillator oscillating at the receiver\'s IF (intermediate frequency) beats with the incoming signals in either CW or SSB and the resultant audio frequency goes to the AF amplifier.

Optimizing weak signal reception on the HF bands, particularly in the presence of strong local QRM, often necessitates specialized receiving antenna systems. This resource details the _HI-Z Antennas_ product line, focusing on phased vertical arrays designed for superior noise rejection and directivity. It covers components such as the 4-Square and 8-Element array controllers, which allow for rapid switching of receive patterns, and dedicated low-noise preamplifiers to improve system sensitivity. The site also presents various bandpass filters, crucial for mitigating out-of-band interference and enhancing the dynamic range of the receiver. The HI-Z systems are engineered to provide significant front-to-back and side rejection, often yielding **20-30 dB** of attenuation to unwanted signals, which is critical for DXing and contesting. Users can achieve a notable reduction in local noise, allowing for the discernment of signals that would otherwise be buried. The array controllers facilitate quick pattern changes, enabling operators to null out interference or peak weak signals from distant stations, effectively extending the reach of their receive capabilities by improving the signal-to-noise ratio.

A project with schematic to build a receiver for 80 meters band by VK1PK

TenTec Receiver RX 320 D Review by DF9CY

Collection of several Crystal Radio receiver circuits with schematics diagrams and pictures

The 80 metre fox-or/test transmitter is a small low power transmitter which is designed to be used as an alignment aid for running up 80 metre foxhunt or ARDF receivers. It is also usable as a micro transmitter for fox-or-ing events.

The idea makes use of a very simple direct conversion receiver on the band of interest.

A full superhetrodyne SSB fox hunting receiver kit

How to run an SDR Receiver on the Android Google Nexus 7 using SDR Touch App and an RTL-SDR dongle, review and costs by IW5EDI

An illustrated modification for the Icom IC-R20 receiver to locate and use the unfiltered audio.

Kenwood TS-2000 Transmit / Receiver eSSB Modifications by N3GX

80 metre ceramix VXO with schematic and assembly instructions

A nice tutorial and the basics of the software defined radio, SDR, and links of software defined radios to JTRS, and general SDR receiver technology.

Software defined radio products. Maker of AFEDRI SDR a direct sampling Software Defined Receiver by 4Z5LV

This converter uses the popular NE602 mixer/oscillator chip and allows reception of signals below 500 kHz on a 3.5 – 4 MHz HF receiver

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

Bonito, butel wavecom and bogger products dealer. Accessories to decode encode and process radio communication transmissions for Radio Receivers, Transceivers and Scanners

A simple direct conversion receiver for 80m. The receiver covers 3.51 MHz - 3.60 MHz and 3.64MHz - 3.71 MHZ - CW and Phone portions by M0DGQ

Friis-It NF is the first iPhone OS based application that allows you to calculate noise figure, system sensitivity, and cascaded gain for an RF Receiver system

Build and run your own ADS-B receiver for 100 USD with a Raspberry Pi

Article on a QRSS receiver for 30 meters band

A searchable database of online websdr receivers, lists OpenWebRX, KiWi SDR and WebSDR from all over the world, providing a web interface to search and filter links to websdr

Commsaudit uk, i/q quadrature , hf receivers, rf, multicoupler, multicouplers, switch matrix, antenna matrices, masthead amplifier,, vhf receiver, uhf,

This windows software includes an easy to read display with features designed to give you accurate and enhanced control of your ICOM IC-R20 Communication Receiver. Commercial 35 USD.

Receiver performance test of the Icom IC-7610 transceiver done by Rob Sherwood

Christoph Petermann DF9CY DRM demonstration receiver project including Circuit Diagram and component list

IK2PII describe here a simple direct conversion receiver, thinked for QRSS and DFCW communications, as companion of ARGO or SPECTRAN programs.

A page dedicated to the Heathkit GR-81 Regenerative Receiver

This project is a Software Defined Radio Receiver. It has a frequency range of 24MHz 1.2GHz. It can demodulate AM, FM, USB, LSB with selectable bandwidths of 600, 2400, 2800, 3200 and 6400Hz. Using a simple RTL-SDR Dongle and Raspberry Pi 3 computer using GNU RADIO

This walkie is sold without the wide band receiver enabled, this is, only 144 and 432 MHz band

An interesting article on grounding and receiver noise

TYT Electronics boasts of 15-year experience in two-way radio manufacture. Produce DMR transceivers, handhelds, receivers and mobile radios, analog amateur radio and commercial VHF transceivers

Receiver performance review of the Kenwood TS-890S HF,50MHz,70MHz amateur radio transceiver by Sherwood Engineering

This page describes how to make the inexpensive Ten-Tec model 297 noise blanker work with the Drake R-4C receiver.

Amateur radio products,wire and yagi antennas, SDR Receivers, upconverters, pre-amplifiers, towers and RTL funcube dongles by CT1FFU

SPX Communication Technologies, operating under the TCI International brand, presents a range of radio frequency (RF) solutions primarily for government, defense, and commercial sectors. The offerings include advanced systems for spectrum monitoring, communications intelligence (COMINT), and high-frequency (HF) and medium-frequency (MF) broadcasting and communication antenna systems. Specific product lines encompass _Blackbird_ COMINT systems, _Scout_ spectrum monitoring receivers, and various antenna arrays designed for robust performance in challenging RF environments. The resource details the capabilities of these systems, such as wideband signal detection, direction finding (DF), and signal analysis, crucial for intelligence gathering and regulatory compliance. It also highlights the engineering behind their antenna designs, which are optimized for specific frequency ranges and operational requirements, including high-power broadcast applications and secure military communications. The information presented emphasizes the integration of hardware and software for comprehensive RF situational awareness. The company's focus on empowering partners to "Command the Spectrum" underscores its commitment to delivering critical tools for signal interception, analysis, and management across diverse operational landscapes.

Mobile RFI, often manifesting as persistent noise in the receiver even with the antenna disconnected, frequently originates from the vehicle's power supply system. This guide details systematic troubleshooting steps, beginning with isolating the radio from the car's 12-volt supply to confirm the power system as the noise source. It emphasizes the critical importance of drawing power directly from the battery using **heavy gauge wire**, bypassing the fuse block to leverage the battery's natural capacitance for RFI suppression and ensuring a solid RF ground. Proper routing of power lines through the firewall is also covered, advocating for dedicated grommeted holes to prevent inductive coupling from other wiring harnesses. The article stresses the necessity of fusing both positive and negative leads from the battery, a crucial safety measure to prevent damage to the rig and mitigate high-current risks should the battery's engine block ground become compromised during service. Addressing **alternator whine**, a common high-pitched noise that varies with engine speed, the resource suggests checking battery connections and the alternator-to-battery harness for looseness or corrosion. It also mentions the utility of adding an external RF noise suppression capacitor in parallel with the alternator's internal capacitor for enhanced filtering, and the effectiveness of commercially available in-line power supply filters.

Crystal receivers, construction projects and plans, old-time crystal sets, hints, crystal receiver store.

A Progressve Communications Receiver by W7ZOI and K5IRK. First published in the November 1981 QST

Featuring Eddystone, Classic British receivers (a history from 1898 - 1973) and Hubble-Bubble a personal web page

How to receive automatically NOAA wather satellite images with a Raspberry Pi and a RTL SDR. This project requires a Raspberry Pi 3 Model B a common NooElec SDR Dongle and a QFH Antenna in the attic. Article explains how to setup and configure software but no instructions on antenna.

The WB5RVZ Genesis Radio G40 build log documents the construction of a 5W QRP 40m SDR transceiver kit, detailing each phase of assembly from power supply to RF filtering. It provides specific component lists, parts placement diagrams, and testing procedures for stages like the local oscillator, Tayloe detector, and RX op-amps. The resource highlights discrepancies between documentation versions and offers practical advice for builders, including a "virtual build" approach to preemptively address potential ambiguities in component identification and placement. It also addresses a specific "VK6IC Fix" for early board revisions, involving trace cuts and jumper wires for improved performance. The build log presents measured voltages and expected current consumption for various stages, such as the 4.9-5.0 Vdc on the 5V rail and under 100mA for RX current. It outlines critical adjustments like image rejection tuning, a common procedure for direct conversion receivers. The resource also includes practical tips for handling components like the 2N3866 transistor and its heatsink, emphasizing pre-assembly. It details the winding of two 1.45 uH toroidal inductors on T50-6 cores with 17 turns of #20 AWG wire, crucial for the RF path.

Suburban amateur radio repeater is a wider coverage machine with six receiver sites in the chicago metropolitan area.

Rack Mounts for ham radio transceivers and receivers

Receiver dynamic range is the ability of a receiver to receive a weak signal without loss of readability while a strong signal is present.

Makers of QRP HF General Coverage Transceivers you can build. The Home of BITX transceivers, uBITX General Coverage Receiver-Transmitter. A general coverage, 10 watts HF SSB/CW transceiver kit with features you NEED for operating ease, convenience and versatility. It works from 3 MHz to 30 MHz, with up to 10 watts on SSB and CW, with a very sensitive receiver.

These pages document some of the experiments with KB9YIG\'s Soft Rock 40 receiver