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Design guidelines for Op Amp audio preamplifier circuits by Mike Martell N1HFX

An engineering oriented organization specializing in the design and manufacture of high performance parabolic antennas, 3dB high power RF couplers, Antenna power splitters, directional RF couplers and more items for RF transmission from HF through Microwave frequencies.

Grahams Goldcoast Australia Radio Scanner Frequencies

This is an interactive design package for designing analogue (i.e. hardware) filters made of inductors and capacitors (Ls and Cs).

The document is a technical guide on designing RF filters for radio frequency applications. It covers topics such as interference suppression, band-pass filters, and low pass filters, with a focus on filter design and circuit filters.

A page dedicated to antenna coil home brewing and coil design by VE6WZ

DIY a Wi-FI Helical Antenna for better performances, a project by PA0HOO i Dutch end English

Ebook by Akira Matsuzawa Tokyo Institute of Technology, Building blocks in RF system and basic performances, Device characteristics in RF application , Low noise amplifier design, Mixer design and Oscillator design

A danish only scale diagrams designer, usefull to draw front panels and dial scale knobs, windows freeware.

Interesting article on how build your own field day antenna

The design and feeding of driven elements for VHF/UHF Yagi antennas , modeling, observations and some case studies by Graham Daubney F/G8MBI

The information in this article has come from many amateur sources, the most notable was from WA6TEY (sk 1985) Ray Frost, who was a pioneer of VHF Quad designs and one of the best Southern California Transmitter Hunters. Ray built hundreds two meter quads in single and paired configurations as well as his famous mobile radio direction finding quad.

manufacture and sell unique, high quality, amateur radio products like HF and VHF antenna mounts

Fill out the form to design a bandpass filter as described in the January 1985 issue of Ham Radio Magazine. These filters are generally limited to frequencies above 200 MHZ because their size is slightly longer than 1/4 wavelength

Antenna designs that K5TR have collected from various sources.

ATV 432 MHz AM transmitter schematic

Windows Magnetic Loop antenna design software by DG0KW in Detusch

Stub sketch notes. Attenuation coax stub schematics

This is an interactive filter design package, for designing digital filters

Examining the _Angle of Radiation_ and its impact on amateur radio operations, the resource provides insights into optimizing antenna performance for DX and local contacts. It features a design for SPOTTO, a direct conversion high-performance universal DSB transceiver, detailing its construction and operational characteristics for homebrew enthusiasts. Additionally, the site presents a 7-element VHF high-gain antenna design, offering practical schematics and expected performance metrics for those seeking enhanced gain on VHF bands. The resource also covers the development and popularity of the _FT8_ digital mode, highlighting its effectiveness in weak-signal conditions and its role in special event operations like the FT8DMC anniversary. It includes information on Hamfest India 2023 and the Lamakaan Amateur Radio Convention, providing dates and organizational details for significant Indian amateur radio gatherings. Technical articles on Direct Digital Synthesizers (DDS) VFOs and low-cost multifunctional frequency counters offer practical project ideas for radio amateurs.

Amateur radio setups for portable and emergency situations.

Design of a 40 meter Vertical antenna

Sunstone.com PCB123 PCB download software. Review Sunstone quality pcb design software. Free PCB software download for all of your business needs.

How to design narrowband bandpass filters

Online calculator, Butterworth Bandstop (Notch) Filter Designer

Around 200 electronic circuits in pdf format or images, There are also over 1000 links to useful electronics, freeware, open source websites. There are some 100 useful documents, software and pcbs too. Mainly industrial electronics, instrumentation. Covers Various aspects of electronics and basics of circuit design.

Taking the Raspberry Pi 2 for a Test Drive with GNU Radio. Installing GNU Radio and receiving aircraft radar with a USB TV tuner

This video will provide a foundation for understanding how power amplifier circuits work. If you are new to High Frequency Power Amplifier Circuit Design, this is the place to start.

Desgining crystal filters and find out crystal data by measuring it.

Online high pass filter design page with introduction to high-pass filters by K7MEM

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.

Design Guidelines for JFET Audio Preamplifier Circuits By Mike Martell N1HFX

This site is dedicated to design and analysis of micro- and millimeter wave filters from 0.5 to above 100 GHz.

This code practice oscillator project uses a 555 timer IC. Includes a Schematic Diagram of the morse code oscillator

Javascript filter design page with introduction to low pass filters by k7mem

The 160-meter amateur radio band, spanning 1.8 to 2 MHz, was historically the lowest frequency amateur allocation until the introduction of the 630-meter and 2200-meter bands. ITU Region 1 allocates 1.81–2 MHz, while other regions use 1.8–2 MHz. This band, often called "Top Band" or "Gentleman's Band," was established by the International Radiotelegraph Conference in Washington, D.C., on October 4, 1927, with an initial allocation of 1.715–2 MHz. Effective operation on 160 meters presents significant challenges due to the large antenna sizes required; a quarter-wavelength monopole is over 130 feet, and horizontal dipoles need similar heights. Propagation is typically local during the day, but long-distance contacts are common at night, especially around sunrise and sunset, and during solar minimums. The band experienced a resurgence after the LORAN-A system was phased out in North America in December 1980, leading to the removal of power restrictions.

Resources for custom battery chargers and power supplies from powerstream

Design for a quarter wave vertical antenna, for the top band in use at V31YN

If you want to design vertical antennas you can find all theory and formulas used to model a vertical aerial calculating capacitance, reactance, building the inductor and calculating resistances. Includes an excel spreadsheet to calculate efficiency.

Build you own RF probe, measure the level of RF voltage present at a particular point.

DesignSpark PCB is the world's most accessible electronics design software, specially designed for Rapid Prototyping and turning your circuit ideas into testable boards faster. Easy to learn and easy to use, DesignSpark PCB is free and can you can download DesignSpark from this site.

Demonstrates the complete design and development process for a **Low Noise Microwave Amplifier** (LNA), beginning with conceptual design and progressing through prototyping. The tutorial series covers the initial stages of a single-ended first gain stage, focusing on critical parameters such as noise figure, gain, and stability. It systematically details the theoretical underpinnings and practical considerations for achieving optimal performance in microwave frequency applications. This resource provides a structured approach to LNA construction, enabling radio amateurs and RF engineers to understand the iterative steps involved in realizing high-performance receive-side amplification. It offers insights into component selection, impedance matching networks, and the measurement techniques required to validate design specifications, particularly for **microwave** band operation where noise performance is paramount.

Redesigning CDE rotator control meter scale for north-centered operation

Antenna design for Horn Antennas

Both Watts and Volt-Amperes are units of measurement for electrical power. Learn what is the difference

Online Constant - k Lowpass Filter calculator

The collinear antenna, or Marconi-Franklin antenna, is an omnidirectional, high-gain antenna composed of in-phase half-wave dipoles aligned vertically. By using quarter-wave transmission line segments, it maximizes gain at a low horizon angle, outperforming a half-wave dipole. Adding segments increases gain but narrows bandwidth. A popular DIY version, the CoCo antenna, uses half-wave coaxial cable segments connected by non-radiating transmission lines. Built with stable velocity factor cables, a matching quarter-wave sleeve balun, and ferrite rings for attenuation, the antenna achieves performance comparable to commercial models.

KE7X Elecraft K3 operating manual

EDC is an amateur radio dealer for Heil Sound, Elecraft, Vibroplex and Force 12 antennas in Japan

Couplings Designer for iPhone. Modern advanced filter synthesis using coupling matrix techniques. There's a free LITE version limited to 4th order filters.