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How to receive JT-65 signals using a cheap RTL-SDR dongle with the 820T2 tuner chip

The latest info on the world of radio including:world,shortwave,pirate,digital,mw,lw news,links.

Technical specification by Universal Radio

Pictures and description of a SteppIr vertical antenna setup in a small backyard using DX Engineering radial plates.

Presents the construction of a 2-meter **Skeleton Slot Yagi** stack, detailing the design process and practical considerations for VHF operation. The author shares insights from building and testing this antenna, emphasizing its performance characteristics for local and extended range contacts. The project outlines the specific dimensions and materials used, providing a clear path for other radio amateurs to replicate or adapt the design for their own stations. The resource covers the unique aspects of the Skeleton Slot radiator, explaining how its geometry contributes to gain and pattern control. It includes discussions on impedance matching and feedline considerations crucial for optimizing power transfer and minimizing SWR. The article draws on real-world testing, offering practical results that validate the theoretical design. This project serves as a valuable reference for those interested in custom VHF antenna solutions.

A 200 kHz bandwidth digital transmission system for image transfer in the Amateur Service is under development, specifically targeting VHF allocations. John B. Stephensen, KD6OZH, leads this project under an FCC Special Temporary Authority (STA) valid until September 10, 2006, authorizing emissions up to 200 kHz bandwidth in the 50.3-50.8 MHz segment. Current regulations typically limit bandwidths to 20 kHz on VHF amateur bands, making this STA crucial for testing wideband digital modes. The modem, a modified **OFDM** (Orthogonal Frequency Division Multiplexed) unit, was initially tested on the 70-cm band. It splits a high-rate data stream into multiple low-rate subcarriers to mitigate multipath echoes. The system uses a DCP-1 card with a Xilinx XC3S400 FPGA and Oki Semiconductor ML67Q5003 microcontroller. The transmitter, located at 36d 46m 30s N, 119d 46m 22s W, generates 150 WPEP into an 8 dBi gain vertical antenna, while the mobile receiver uses a Ham-stick. Three data formats for 50, 100, and 200 kHz channels are being tested, with encoded data rates of 96, 192, and 384 kbps. Verilog code for the VHF OFDM modem is 95% simulated, with modifications from the UHF version including increased filter coefficient precision and a change from Ungerboeck **TCM** to BICM for improved performance over fading paths. Final tests will involve one-way over-the-air measurements of bit error rates and coverage area.

An homebrew project of a full wave delta loop antenna for the 40 meters band with dimensione, picture and assembling instructions in Indonesian

KD8KSB realization of the CJU satellite antenna that allow similar performance to the arrow antennas.

A wire antenna feeded with an unsymmetrical feed and a 1:4 balun can be tuned from 6 to 80 meters band but can be noisier than a dipole and cause RF in the shack

Pictures and description of a homemade 1.3 GHz and 2.4 GHz RF Signal Source

ik3qar Logs on line of IOTA EU131 / IIA expeditions

Windows shareware contest log program for the CQ WW DX contest. The contest log software offers a Network version capable to run over a local area network in order to allow several pc to update a single shared contest log file. Windows XP through Windows 10.

KB22UT Article on how protecting ham radio station and in particular I/O Lines such as AC power, coax cable, control circuits, telephone line.

The article presents a detailed examination of 40-meter wire antenna performance, specifically focusing on the impact of antenna height on gain and radiation patterns. It quantifies how a 40-meter dipole at 1/8 wavelength above ground exhibits a high-angle radiation pattern, while raising it to 1/2 wavelength significantly lowers the take-off angle, improving DX capabilities. The author, VE3VN, leverages _EZNEC_ simulations to illustrate these changes, providing visual representations of the antenna's lobe structure at different elevations. Comparing a single dipole to a two-element wire array, the analysis shows that a 2-element array at 1/4 wavelength height can achieve **3.7 dBd** gain, outperforming a single dipole at the same height. This gain is further enhanced to **5.7 dBd** when the 2-element array is elevated to 1/2 wavelength, demonstrating the practical benefits of optimizing both element count and height for improved signal strength and directivity on the 40-meter band. The findings offer practical insights for hams seeking to optimize their wire antenna installations.

Several HD video overlay devices are offered, including the GeoStamp HD, which overlays GPS latitude, longitude, heading, speed, altitude, date, time, and depth onto AHD, HD-TVI, and HD-CVI (720p/1080p) video sources. The VideoStamp HD allows user-defined text overlays on similar HD video inputs, while the VideoStamp Keyboard HD enables text input via a PS/2 keyboard for video overlay. For commercial applications, the PostMark HD integrates with cash registers and POS terminals to overlay transaction data onto security camera feeds. Beyond HD video solutions, the DTMF-8 DTMF Decoder provides remote control capabilities for up to eight devices or relays using touch tones from a radio or other audio source. This decoder supports four operational modes and includes password protection, storing all settings in non-volatile EEPROM memory. The product line also includes standard definition OSD, RS-232, GPS, and POS text inserters, along with various DTMF encoders and DVR solutions.

A no ground antenna solution for backpackers, balconies or plastic car bodies, like RV or other portables uses where is difficult to find a good counterpoise by PD7MAA

Android app by VE3VN that show view of night, day and terminator around the globe. This gives a strong hint of which bands and compass directions to focus on for best results.

Log Search for 9M0L Log online

Homebrewing dummy load by M0XPD

Special logging program, optimized for mobile, portable, and field operations. This software exports data in the ADIF which then may be imported into your general logging software, or online services. Currently available for Android.

Setting up a new antenna Mast for dipoles at VE3VN

Demonstrating the construction of a short dipole antenna tailored for the 60 meter band, this resource provides detailed instructions for radio enthusiasts with limited space. The design incorporates inductive loading using two inductors (L1/L2) made from PVC tubes, allowing for effective operation on 5 MHz. The antenna consists of 12 meters of wire, divided into four sections, with specific dimensions and materials outlined for optimal performance. Results from users indicate that this antenna can significantly enhance DXing capabilities on the 60 meter band. Feedback from operators suggests that while the design is effective, adjustments may be necessary based on individual setups, such as coil diameter and wire gauge. Many users report successful construction and operation, with some experimenting with variations to improve resonance. The practical application of this antenna design has led to successful contacts and improved signal quality, making it a popular choice among 60 meter band operators.

Review of Logikey K-5 Keyer

VK9MT Online Log Search - Mellish Reef 2014

An interesting article about planning and testing beverage antennas for 80 and 160 meters in a rural location

Testing log wire antennas and a unun by G0KYA

An home made end fed half wave antenna with a tuner box by NG0R

Cutting out the noise using a simple coax filter to improve the poor front end filtering

A complete restoration of a Heathkit SB-200 HF power amplifier

Photos and description of an EAC R-390A

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

LinLogBook is an logbook for hamradio and it is based on an sql database. It can be widely configured by the user.

A simple UHF Crystal Radio wired up to check for reception of VHF/UHF signals in the vicinity of the shack.

FO8RZ Tahiti island OC046 by F5PHW from 2009 to 2011.

NVIS antennas, also known as Near Incident Vertical Skywave antennas have a high angle of radiation. Something on the order of 60 degrees, to straight up to 90 degrees. A portable, easy to setup and cheap nvis antenna project.

How to connect and key Power Amplifiers to Kenwood TS 590 or TS 990. How to home made custom Remote cable to key power amplifiers by JG1VGX

An economical dipole for simple QRP HF homebrew rigs

A custom modification RC-D710 GPS-INSIDE mod.

Modoification for the Yaesu FT-8800 144/430 MHz dual band FM transceiver

A homebrew four elements log periodic antenna for HF bands

Homebrew Tubes/LDMOS amplifiers, Antenna, accessories, adventures in 9Q, DX, UN missions, Contests, and more.

Attenuating output power to Yaesu FT-817 and interesting article for really QRP operations by PA1B

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.

Cushcraft A3S performances with the A743 kit to add 30 and 40 meters

Examine the function and operation of a common mode choke and the way it reduces unwanted interference. Common Mode Choke vs. Single Choke

The 9W2VVH blog documents the amateur radio journey of Hussairy, focusing on his station setup and operational experiences from Malaysia. Content includes details about his _Yaesu FT-857D_ transceiver, which serves as the primary rig for HF, VHF, and UHF operations, often paired with a _G5RV_ antenna for HF bands. The site also features discussions on various aspects of ham radio, such as antenna experimentation and QSL card exchanges, reflecting a hands-on approach to the hobby. Operational updates frequently cover DX contacts and local ragchews, providing insights into propagation conditions and operating techniques from Southeast Asia. The blog serves as a personal log and sharing platform, showcasing the practical application of amateur radio equipment and fostering connections within the global ham community.

Log Online ZK2C 2012

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

Developing a protection plan against lightning

The Icom AH-4 autotuner operates efficiently across multiple HF bands, providing seamless automatic tuning for antennas from 3.5 MHz to 54 MHz. Its robust design allows for outdoor installation, making it suitable for field operations and fixed stations. The unit interfaces with Icom transceivers via a control cable, enabling automatic band switching and tuning. The AH-4 is capable of handling up to 120 watts of RF power, ensuring compatibility with most amateur radio setups. Its weather-resistant casing and compact form factor make it a versatile choice for operators requiring reliable performance in diverse environments. Field tests demonstrate the AH-4's ability to maintain low SWR across its operational range, enhancing signal quality and transmission efficiency. Compared to manual tuners, the AH-4 offers significant time savings and ease of use, particularly in rapidly changing band conditions. Its integration with Icom radios simplifies operation, eliminating the need for manual adjustments. The autotuner's performance is consistent with other high-end models, providing a cost-effective solution for amateur operators seeking dependable tuning capabilities without sacrificing performance.