From the sortwave radio audio archive, a collection of recordings of several spy numbers stations, russian, spanish, cuban audio recordings

The intention was to determine also very small SWR ratios with small power exactly. With this SWR meter, for example, the inputs of RF amplifiers with power < -20 dBm can be measured. In German

A software defined receiver located in Tuscany Italy with a Windom antenna convering HF bands

The Trainer is based on a simple modular built STEM/game platform, plus newly developed interactive software,it contains six training routines, easy to advance, and consists of various learning aids. You select them from a menu. Feedback for menu selection is given audibly and through an LED display and serial monitor.

How to build a Simplified Arduino CW Trainer, this is a version that does not need a keyboard.

A simple 3D Paddel CW Key made of plastic with a standard 3d printer

An attenuator is needed for example, to generate defined levels starting from a reference level. With this attenuator control a measuring instrument can be calibrated.

Basically, this antenna is a 23-foot wire fed through a 4:1 un-un transformer. This antenna can be easily used in portable operation, for operating all bands from 40-10 meters.

A mid-power portable/handheld SSB transceiver for 14MHz

A Rig control CAT interface schematic suitable for both the Yaesu FT-817 and FT-100 transceivers.

This type of antenna is a popular antenna design as the performance is very good across the HF bands and requires little or no tuning. It’s a dipole fed off center with a 4:1 balun at the offset feed point. The antenna shown covers 80, 40, 20 and 10 meters. The formula can also be used to adjust the overall length to cover more or fewer bands and the resulting overall length. 160-10m, 80-10m or 40-10 meters depending on your available space. Other bands will require a tuner.

Inverted L antenna, even if not completely freestanding, it only requires one line to be lauched into a tree to support the end of the horizontal wire. This project is done with a 31-foot Jackite pole for a support and uses six 15-foot radials and one 33-foot radial.

With some fantasy the circuit can be easily assembled on a small scrap of pre-perf board,and then fitted in the DB9 serial connector shell. The interface requires two NPN transistors and few more passive components.

A collection of pictures for a mobile antenna setup for T-hunting.

An omnidirectional horizontal polarization antenna for 2 meters band in Italian

Undesrtanding three band conditions indicators to undestand current and future propagation conditions, solar flux, Ap and Kp indices

An Hentenna project for the six meters band. The standard size of standard hentenna is width 1/6 wavelength x height 1/2. The antenna build in this project is a full wavelenght antenna for the 50 MHz providing a 6.8 dbi gain.

SDRangel is an Open Source Qt5 / OpenGL 3.0+ SDR and signal analyzer frontend to various hardware TX & RX Software Defined Radio. SDRangel uses sample source plugins to collect I/Q samples from a hardware device.

SPC, series parallel capacitance, tuner project. Built properly, it will match a very wide range of impedance. It also maintains good harmonic attenuation.

A small active voltage probe antenna to aid reception on the LF bands

Listen to online WebSDR located in Andorra Europe. Four receivers on 60m, 20m, 40m, and 80m, connected to a dipole antenna direction East/West

A balun is a MUST for dipoles or similar antennas when they are feed with coaxial cable. From the RF point of view, the shield can be modeled as two conductors, the internal shield (the real shield, this is, ground) and the external shield, who is really far to be ground. In this way, your dipole has 3 arms, the two from the dipole and the coaxial cable shield (external face)

HF Skeleton Slot An antenna system with a difference.

Remotely-Operated 1200 Baud AX.25 Narrowband Packet Radio and APRS on a Baofeng UV-5RA and Raspberry Pi 2

This article is designed as an introduction to some of the more popular digital modes. From HSCW to FT8 and interesting article with detailed information on popular and historical amateur radio digital modes.

BlueDV Android is DMR/DSTAR and Fusion hotspot software for Android 4.x and higher. It supports DSTAR (DEXTRA, DPLUS, DCS), FUSION (YSF, FCS), DMR ( Brandmeister, DMR+)

Soundmodem is a free software defined dual-port Packet-Radio TNC that implement a soundcard as a modem and supports AX.25 protocol. Soundmodem has been tested on Windows XP, Vista, 7, 8, 10 and has proved stable in operation. The Soundmodem may be used to build EMCOMM, APRS, BBS, Node station, for satellites

What is a QSL Card and what should be the content of each QSL card, collecting cards, electronic QSL LoTW eQSL, QSL Bureau, and QSL managers.

With Doozy for Windows you can make QSO’s via your Windows PC on DSTAR ( DPLUS, DEXTRA, DCS and XLX ). There is no need for a hotspot. Just connect your ICOM IC-705 to your Windows PC with an USB datacable and connect it to your favorite DSTAR reflector/repeater.

System Fusion is Yaesu’s implementation of Digital Amateur Radio, utilizing C4FM 4-level FSK Technology to transmit digital voice and data over the Amateur radio bands

System Fusion is a digital communications mode for voice and data, including pictures. It utilizes a customized, yet open, C4FM FDMA standard. An introduction to Yaesu System Fusion by Wireless Society of Southern Maine

This page is a detailed description of a 6CL6 and 807 valve transmitter. The page includes the complete circuit diagram to build this transmitter and several pictures

This antenna looks like an inverted L antenna, yet it is not, it could also be viewed as a 160m off-center fed dipole antenna, it looks more like an end-fed 1/4 wave 160 meter antenna.

SmallDV is an embedded FreeDV for Raspberry Pi from Matt KK5JY

HFN (Hands Free Nanokeyer) is a 3D Printer made morse keyer. In this project the athor shares the STL printer model files for the 3 versions build.

The SW-3B is a Three-band CW QRP transceiver, Weight 180g, output power 5W at 12v, 2W at 9v, works on 40 30 and 20 meters band

FreeDV uses an audio codec as a software based modem to decode and encode the voice and text data from your computer. The data is encoded and then is transmitted over the HF radio using AF signals that can then in turn be decoded by the receiving station.

Ionospheric Propagation of Radio Waves in Action, How Do Ionized Layers Form to Enable Ionospheric Propagation of Radio Waves, the foundamental role of F layer, and the role of the other ionized layers

The Union of non-governmental organizations “The Ukrainian Amateur Radio League” (UNGO “UARL”) was founded in December of 2015. Currently, there are about 1500 members in the League, representing most regions and cities of Ukraine.

This article help on explaining what you need to start with amateur radio. By using a local ham radio club station to purchasing second hand radio equipment and how to get help on installing antennas.

This is a CW 1W transceiver with only three transistor. The author has been able to make QSO by this little transceiver with Saga, Asahikawa (domestic far distance city),and Indonesia and Taiwan.

Isotron antennas are antennas of reduced size, without tuning. On 40 and 80m band, it is made of two plates into v whose angles are connected by a coil. In this article the description of a home made realization for the 40m band.

A PDF File of a Maria Maluca multiband HF antenna with schematic diagram, dimension and plan

Some useful information for tuning mobile antennas gained the hard way. A collection of useful tips and hints on adjusting and matching a mobile antenna and methods of feeding a mobile antenna

A website with a large collection of world flags pictures in GIF format divided per continent. Includes flags of US and Canada states

A collection of some electronics hobby projects by KC6QHP that includes microwave transverters for several radio frequencies such as 79 GHz, 47 GHz 24 GHz and 10 GHz. All projects includes detailed pictures of components, like voltage regulator boards, RF Decks, sequencer and protector board and receiver details.

Notes on installing the miniVNA PRO software, making a calibration standard, a trap tuning loop.

Author found a ratio between the lengths of the sides of the Delta Loop that give reasonably low SWR into a 50 ohm coaxial cable almost independent of the high above ground and other surroundings. This ratio also gives good results no matter orientation. Includes an online delta loop antenna calculator.

It is possible to add a very small Bluetooth transmitter to the 3.5mm headphone jack and then use a pair of Bluetooth headphones around the shack. In this article Author provides some tips on choosing the proper Bluetooth interface.

Description and online calculator for Log Periodic Dipole Arrays LPDA are directional antennas featuring a relatively constant characteristics across a wide frequency range.

The Quarter-wave stub can be used for many purposes. If it is left with an open end it can be used as a notch filter to attenuate certain frequencies. A quarter wave length of a transmission line can also be used as an impedance transformer, to know more about the Quarter-wave impedance transformer

World-Wide 50MHz Beacons database maintanied by G0LGS provide a fully sortable table available also in a google map format

We use the term air core coil to describe an inductor that does not depend upon a ferromagnetic material to achieve its specified inductance. This covers the cases where there really is just air inside as well as windings upon a different insulator such as bakelite, glass or PTFE etc. Do you need an air coil?

Online log for 3D2RRR dx pedition to Rotuma

Article from 73 Amateur Radio Today about experimenting on ferrite loops transmitting loop antennas for 80 and 160 meters bands.

A project about reversible unidirectional Beverage antennas plus a remote switching system conveniently controlled by the operator

This is a very small vertical 160m antenna that fits in the loft of even my small house. It was built as a way of getting a signal out on 160m for local AM contacts, but the local noise level was far too high to allow it to be used at night for this purpose. However, on WSPR it did a pretty good job with WSPR spots from a very long way across Europe being received when running 2.5W out.

Aircraft scatter is easily seen on the spectrogram window of digital communication apps, when you know what to look for. Examples of real aircraft scatter usage on six meters band

The Raspberry PI 3+4 has proven itself as an amateur radio computer. Both at home as the main computer in the shack but also on the road. It is small, inexpensive and incredibly versatile. The operating system and the most important programs are available for free.

If you want to have a closer look at the weather, you can download software and visually display data.

A two element beam antenna for ten meters band. This home-brew two-element beam is the perfect introduction to rolling your own gain antenna

An homemade 50 Ohm 140 W dummy load based on an idea and project by ON5DB Renaud.

The (tr)uSDX is a 5-Band / Mulitmode QRP Transceiver in Pocket Format (90x60x30mm – 140g). It features a highly efficient Class E PA and Supports CW/LSB/USB and AM/FM. Right now it covers 80/60/40/30/20m and in Future there will be support for 17/15/12/10m

A home made CW keywer based on the W5UHX board.

Spectrum and oscillo with tuner TV 40 MHz to 860 MHzh ome made project. This projects foreseen a multi function device providing a spectrum analyzer, scope and a voltmeter.

How to enable a full TX coverage on the Yaesu FTDX101D the european version.

Remote Control Panel for ICOM IC-M710

The Interlock Monitor (IM) program allows you to control and monitor the Interlock device from any computer in your network. The Interlock is an equipment designed to be used by contesters where they need to check, supervise and limit, how many radios are in transmission at any given time