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Layman level explanations of "seemingly" mysterious LF MF and HF propagation occurrences.

Discussion groups for Shortwave Listening, Propagation, Amateur Radio, and related topics.

An unconventional antenna family, the VHF/UHF Zigzag Dipole Antennas. Design, theory and practical construction, transformation and balancing with a half wave balun.

On this page are designs for Dual Band 2M / 70cm antennas. All antennas are 50 ohm designed driver. These Yagis have a unique element called a Open Sleeve. 4 Element 5 element and 9 element Dual Band - 2M / 70cm antenna projects

The advantage of 5/8 wave antenna is that it has the lowest angle of radiation and has about 1dB more gain when compared to 1/4 and 1/2 verticals. So the 5/8 should be the favourite choice for DX.

With spectrum analysis of beacon signals, it's possible to see features relating to various propagation phenomonen.

RFI Forum at eHam.net

Sizes of wire as compared to their gauge American Wire Gauge by W8HDU

Yaesu FT817 all band, all mode handheld transceiver article.

An economical dipole for simple QRP HF homebrew rigs

A versatile hybrid synthesizer for UHF and Microwave Projects

A few thoughts on Multi Band VHF Aerials by Peter Ward VK3ZAV

This Magnetic Longwire Balun (MLB) makes it possible to efficiently use a coaxial lead-in cable with all forms of longwires, T-forms or other types of wire antennas, without the need for an antenna tuner.

Assembling installing and tuning the Butternut HF9V multiband vertical antenna

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

VHF channel usage, making a mayday call, and related informations

An 80m transceiver using just 14 parts plus crystal and earpiece

Mounting antenna close each other. Distance calculations and tips on setting up antennas by KB9VBR

Article on RTL SDR dongles to receive UHF VHF ham radio bands

This method of construction can be used on most UHF through \"low\" microwave Yagis, and is especially useful for the 33, 23 and 13 cm bands

HFpack provides an information exchange about transceivers, antennas, systems, HF packs, propagation, new developments and techniques in HF portable operation. Radio Amateurs are invited to participate in egroup and on-the-air nets around the world.

1500 watts of RF output on the 70cm band requires robust amplifier design, a challenge addressed by this project featuring the GS-23b / 4CX1600U Svetlana tube. The resource details the construction of a high-power UHF amplifier, providing insights into component selection and layout necessary for stable operation at these frequencies and power levels.

6m/2m/70cm Yagi Antenna Built from Old TV Antenna This turned out to be a great little antenna. It works the 6 meter, 2 meter and 70 centimeter bands. You can use one common feedpoint or two seperate feedpoints depending on how you would like to connect this antenna to your transceiver.

VHF an above weak siganl site

Details the construction of an **HF converter** designed by M1GEO, George Smart, specifically to extend the frequency range of the FunCube Dongle Pro (FCD) for amateur radio reception. The FCD natively covers 64 to 1,700 MHz, but this project enables reception from 0 Hz to 64 MHz by up-converting signals to the FCD's operational range. It employs a **double-balanced mixer** with a 100 MHz local oscillator (LO) to translate incoming HF signals; for instance, a 1 MHz signal appears at 101 MHz within the FCD's passband. The design incorporates a 7th-order Chebyshev low-pass filter with a 62 MHz cutoff frequency at the input to mitigate image frequencies, ensuring cleaner spectral presentation. George provides the schematic, PCB masks, and Gerber files for replication, noting that Far Circuits also offers PCBs. The resource includes test results for the low-pass filter and measurements of LO leakage, identifying -36.8 dBm at 100 MHz as a potential sensitivity concern. M1GEO discusses potential improvements, such as adjusting the mixer's LO drive, adding a balance pot, or incorporating a post-mixer high-pass filter to reduce LO breakthrough. Audio recordings from 40m and 17m demonstrate the converter's performance with WRplus SDR software.

With the bluecat interface it is possibile to connect a Yaesu FT 817 857 897 to a computer or a android smartphone without any cable or interface, using a bluetooth wireless connection

An home made FETer QRP transceiver for the 80 meters band

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.

Excellent article and guide to choose the best RF power amplifier that fit your needs by ON4SKY

This project describes the construction of a real CW QRP keyer with a small microcontrolle

FTB2070 is a memory management program for the VX-120 and VX-170 FM handhelds

Eme meteorscatter Aurora Fai Tropo Tep and more about VHF

Setting up HF10 a solution for those having limited locations and wanting a low visual impact aerial by G4LDS

Operating as a local amateur radio club, the Wireless Association of South Hills (WASH) provides a community hub for hams in the Pittsburgh, PA area, identified by the N3SH callsign. The club engages in a range of activities including the Annual Field Day, the PA QSO Party, and a 2 Meter Contest, fostering participation in various aspects of the hobby. WASH also supports local ARES/RACES efforts, highlighting the critical role of amateur radio in emergency communications during disasters, and facilitates ARRL/VEC exam sessions for new licensees. Beyond contests and emergency preparedness, WASH hosts club picnics and an annual hamfest, promoting social interaction among members. The club maintains VHF/UHF repeaters, which are essential for local communication and extending range for members. Regular activities include a Monday evening WASH NET at 8:00 PM, providing a consistent on-air gathering point. The club's focus on both recreational and public service aspects of amateur radio, from making new friends to providing vital disaster communications, underscores its comprehensive approach to the hobby.

Report on tests done on VHF Radios to understand which are best suited for 144 MHz operation in large signal environments like VHF contests

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.

About Coax Traps, NC4FB examine the operation of coax traps through modeling.

A list mantained by I5WBE of all beacons based in italy

The **TransWorld Antennas TW2010 Traveler HF Portable Vertical Antenna** assembly video provides a visual walkthrough for deploying this popular portable HF antenna. It details the step-by-step process, from unpacking components to final setup, which is crucial for operators preparing for field day operations or DXpeditions. The video focuses on practical aspects, showing how to connect the various elements and secure the antenna for optimal performance. Operators often seek clear assembly instructions for portable antennas like the TW2010 to ensure quick and correct deployment in diverse environments. This visual aid helps clarify potential ambiguities found in written manuals, illustrating the proper handling of the antenna's radial system and telescopic elements. The video serves as a valuable resource for those aiming to achieve efficient operation with the **TW2010 Traveler** in a portable setting. Understanding the assembly sequence can significantly reduce setup time and prevent common errors encountered during initial deployments.

This project is based around the recent HF1 QRP transceiver by Ashhar Farhan, VU2ESE. The transceiver is an interesting SSB design with wide tuning range from 0-30MHz and should cover several amateur bands. The schematic for the transceiver can be found on the Minima mail list in this post with a PDF attachment

These charts show the New Zealand bandplan

A RF Probe circuit for the RADIO frequency experimenter to check the presence of a RF signal and also to measure its strength

Vhf and UHF homebrewers of hardware and antennas. Find help, idea, or someone with just the same interest as you.

NOAA HRPT - High Rate Picture Transmission, the main source of high quality data from polar orbiting meteorological satellites

Presents the VHFDX.EU web cluster, a specialized resource for VHF, UHF, and microwave DX spotting. It details the cluster's functionality, including real-time spot aggregation and a DXCluster Map interface for visualizing activity. The resource highlights its integration with the MMMonVHF backbone, ensuring a robust data flow for monitoring band openings and propagation events across higher frequencies. It also references reviews of the ON4KST and N0UK chat systems, which are frequently used in conjunction with VHF DX operations. The platform offers a mobile-optimized view for on-the-go access to DX spots, catering to portable and mobile operators. It further provides daily ES (Sporadic E) spot summaries, a critical feature for VHF operators tracking this specific propagation mode. The cluster serves as a central point for operators to share and receive information on rare grid squares, contest activity, and general band conditions above 50 MHz.

Article on evaluating HF Power amplifiers and review of popular PA by K0BG

Make and automatic antenna tuner based on Arduino and using economic card. This ATU Project can be installed outdoors and controlled remotely by an rs485 link

Performance of an unloaded ground mounted vertical as a multi-band HF antenna.

VHF UHF Microwave EME Standings, a Who's Who on top in USA

Have you ever thought of setting up a portable HF station for an activity ?