Search results
Query: LF
Links: 622 | Categories: 7
-
This PDF document, authored by KT4QW in October 2004, details the construction and modeling of a dual-band, horizontally polarized hanging rectangular loop antenna for **10 and 17 meters**. The design, adapted from *The ARRL Handbook*, utilizes _NEC4WIN95_ software for scaling and optimization, targeting a 50 ohm feedpoint impedance. The resource includes a bill of materials, step-by-step construction instructions, and a discussion of the antenna's radiation characteristics. It presents NEC-generated elevation and azimuth patterns, comparing the loop's performance to a half-wave horizontal dipole at the same height and frequency. The 17-meter element is centered at 18.140 MHz for low SWR across the phone band, while the 10-meter element is centered at 28.500 MHz. Construction involves 14-gauge stranded copper wire and Schedule 40 PVC spreaders, with the total wire length calculated by the formula: Length in feet = 1005/MHz. The feedpoint impedance can be adjusted by modifying the rectangular aspect ratio. The document specifies hoisting the antenna to at least a half-wave above ground for testing. It notes that a balun was tested and found to have no measurable effect on SWR or radiation characteristics. A 2-meter scale model is presented to illustrate the physical design, and a "rotator" string is incorporated for directional adjustment up to 90 degrees. -
This antenna is very useful for receiving or scanning purposes, but you can use it for transmitting, too. It is 2,94m long and has a pi-configuration (Collins-Filter) for the matching. -
-
Amateur radio towers by Wade Antenna ltd. Wallmounts,masts and accessories, tripods, dmx self spporting towers, telescoping masts -
The ultimate satellite Omni Antenna by Howard Sodja, W6SHP. The Lindenblad antenna consists of four half wave folded dipoles slanted 30 degrees to the horizon, oriented 90 degrees to each other in azimuth, spaced 0.3 wavelength apart -
One of the best antenna values on the market is the LightningBolt Quad. At about half the cost of a tri-band yagi, you get five band coverage with a single coax feedline and excellent performance from a light, low wind load antenna. -
Soundflower is a Mac OS X (10.2 and later) system extension that allows applications to pass audio to other applications. Soundflower is easy to use, it simply presents itself as an audio device, allowing any audio application to send and receive audio with no other support needed. Soundflower is free. -
This is a resonant, half-wave, vertical antenna. It takes up little space in the back yard, was designed for operation on a single frequency 80 meter PSK net, and is reasonably inexpensive to construct by Chuck Hines, K6QKL -
A 5-band (20m-10m) HF antenna - Just 7ft square and great for a small garden. Build it yourself for around 60 GBP. -
An Easy way to Monitor RF, AC or DC current with one instrument by W5JGV -
KN4LF article about a 1/4 wave fan inverted L antenna for 80 and 160 meters band -
Presents _DirLog_, a freeware logging application specifically developed for the 11-meter CB band, catering exclusively to members of the _Alfa Tango Group_. The software facilitates the recording and management of contacts, providing a dedicated tool for CB operators to maintain their station logs. Its development spans from 1997 to 2025, indicating a long-term commitment to its maintenance and evolution by its author, 1AT069 Enio. This specialized logbook offers features tailored for CB operations, allowing users to track their contacts within the 27 MHz band. While primarily focused on CB logging, its structure and functionality could be compared to amateur radio logging software in terms of data entry and retrieval. The exclusivity to Alfa Tango members suggests a community-specific utility, fostering organized record-keeping among its users. -
The octoloop antenna is a length of 25 pair telephone wire inside an octagonal loop shield of 3/4 hard copper pipe -
If you are looking for an easy antenna for your favorite band, you can't go wrong with an halfwavelenght dipole, all you need is 3 insulators and some wire -
-
-
The K8ZT website provides a curated collection of amateur radio resources, encompassing software tools, informational articles, and external links relevant to various aspects of the hobby. It features utilities for _log analysis_, insights into QRP operations, and guidance on obtaining vanity callsigns. The site also includes sections dedicated to shack design principles and general ham radio information, reflecting a broad interest in practical station setup and operational enhancements. Specific software offerings are presented alongside discussions on their application, such as tools for analyzing contest logs to identify operational efficiencies or areas for improvement. The content often integrates personal experience with technical explanations, providing a practical perspective on topics like antenna selection for low-power operations or optimizing station workflow. The resource distinguishes itself by combining software recommendations with contextual information, aiding operators in making informed decisions about their station's technical and operational aspects. -
-
Installing these filters is a big improvement in the quality of the rig of the Yaesu FT-897D -
6m to 40m EndFed Half Wave Antenna project produces an inexpensive, multiband, end fed HF antenna matchbox that is quick and easy to setup and use. -
The free pdf book is a compilation of articles congenial to QRP published on 2003- 2005 years at free e- magazine AntenTop. 17 Mb pdf file. -
The Super J Pole antenna is a co-linear vertical consisting of a number of half wave length vertical elements separated with half-wave length stubs (Tuning stub) feed with a folded matching stub by vk6ysf -
HF QSO/QSL/Award managment, ADIF Import/Export, full version free to everybody. Requires Access 97 or Access 2000 (with JPEG and TIFF filter installed), screen resolution 800x600/1024x768 -
How to create a simple but effective half wave dipole, illustrated instrucions on how to build wire antennas -
Electronic circuit and components layout fot this VHF Preamp -
-
A 40m through 20m QRO End Fed Half Wave Antenna Coupler by Steve Yates - AA5TB -
EI7BA describes a nice selfmade Hexbeam project for a single band version. -
Determine the K-Factor used as a multiplier when constructing half-wave antennas. -
The Double Bazooka Dipole is a half wave dipole with an attempt at compensation of the reactance change that occurs around resonance for a half wave dipole. -
21 mhz half wave ant -very low radiation angle - full size and light weight- all coax matching system - decoupling care to prevent low angle radiation degrade -
There are lots of good designs for matching transformers for receiving antennas. Make it yourself it's cheap and easy, and very high performance. This is the design used in the TRX-9 transformers. -
HeyWhatsThat Path Profiler is an online useful tool to do a Line of Sight calculation between yourself and the another station -
1/2wave vertical antenna for the 6-meterband and a 5/8 ground plane antenna for 50 Mhz -
G8ODE schema to reduce a half-size G5RV to 70 ft. -
Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site. -
A 46ft multi-band antenna for small gardens that works on 80m. An excellent DX performer and is an ideal replacement for your half size G5RV by G7FEK -
The webring that contains lots of links relateed to pirate radio -
G4URH calculations to design your own antennas, ground plane, half wave antennas, Quad Antennas and 5/8 verticals -
A compact Beam Antenna That Can Be Built At Home. Made with lightweight wooden "X" frame with two folded and linear loaded wire elements. The two elements are approximately a half-wave each. -
-
Design your owm HF shiortened dipole. Includes a diagram of a lumped-constant loaded dipole antenna that is intended to fit in available space, rather than requiring a full 1/2 wavelength, at a specified frequency -
This doubet antenna is a half wave dipole antenna easy to build, in french -
-
Dire Wolf is a software soundcard modem and APRS encoder/decoder. It can be used stand-alone to receive APRS messages, as a digipeater, APRStt gateway, or Internet Gateway (IGate). It can also be used as a virtual TNC for other applications such as APRSIS32, UI-View32, Xastir, APRS-TW, YAAC, UISS, Linux AX25, and many others. -
A vertical half-moxon for the 7 Mhz by F6IRF -
Build yourself a postage stamp 40 meter wire dipole antenna that fits in a space a little over 20 wide and works reasonably well at low heights -
The W1TAG LF Receiving Loop is a specialized antenna project for LF reception, designed to mitigate local noise and enhance weak signal pickup on the lower frequencies. This square loop, measuring 6 feet per side, utilizes 14 turns of #12 THHN wire wound on a PVC frame, offering a robust mechanical structure. The design incorporates a series-tuned circuit with a coupling transformer, allowing for tuning from over 400 kHz down to _45 kHz_ using a switched capacitor bank. Construction details include the use of 1.5-inch PVC pipe for the frame, with specific measurements for spreaders and drilled holes for wire threading. The two 7-turn sections of wire are connected at the center, providing an option for a center tap. The loop rotates on a 1-inch steel pipe, enabling directional nulling of noise sources. The tuning unit, housed in a box clamped to the PVC, employs a 1:2 step-up transformer wound on an _FT-82-77 core_ and uses relays to switch capacitance values from 50 pF to 6400 pF, providing precise frequency adjustment. The current setup connects to the shack via 100 feet of RG-58, feeding into a W1VD-designed preamp, with plans for a balanced, shielded twisted pair cable upgrade. -
Communication Concepts, Inc. specializes in providing RF components for both amateur radio operators building their own gear and professionals prototyping circuit designs. The inventory includes a range of products such as HF and VHF amplifiers, splitter combiners, and various filters, catering to diverse applications from QRP to high-power systems. The site details specific components like _Freescale_ and _Motorola_ RF transistors, along with custom semi-rigid coaxial cable options. The offerings extend to parts for ATV, packet radio, and general electronic components, emphasizing quality and service since 1979. Customers can find items like low-pass filters for RFI/TVI mitigation and specialized transformers for RF power systems, covering frequencies from 2-30 MHz Type "H" to 1-80 MHz high-power applications. The resource highlights its role as a supplier for those constructing custom radio equipment, offering components that facilitate projects from basic radio kits to advanced amplifier designs, with a focus on enabling self-construction and cost-effective prototyping.
