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This resistor calculation tool shows which combinations of two resistors, series or parallel, gives a match better than the closest standard value.

his controller uses the Yaesu GS-232 command set to control a Yaesu G-5500 Az-El rotor. The controller was designed to be compatible with the SatPC32 tracking program and should work with any tracking program that supports the Yaesu GS-232 format. This controller has been tested with the Arduino UNO and the Arduino Mega2560.

OK2ZC ex ok2bee homepage with log search and photos

A small antenna for 50 MHz made with copper cable loading coils

Make them simple then Make them work. The LAZY H antenna is a general type of antenna that is in the curtain array family. By placing two 1 wavelength dipoles in a plane that is at right angles to the direction of maximum radiation and keeping the proper in-phase current condition to each element, you can achieve a high gain bi-directional antenna.

A multimeter with standard resistance sorting function

A deep analysis of UHF connectors performance tests, including return Loss of UHF Connectors, Mismatch Loss of UHF Connectors, SWR of UHF Connectors

DXCC status monitoring tool. Maintains database of new worked countries and generate statitics

VHF-UHF receiver covers from 25 to 800 and 900 to 2000 MHz in the following modes: AM, AM-W, FM, FM-W, FM-N, USB and LSB

OL5Z - contest station from JN89AR

A Multiband Slinky Coil for the PAC-12 portable Antenna, can be used also as a dual PAC-12 dipole by James Bennett

Where abilities and disabilities become possibilities

The Tri-pole antenna, a clever modification of a standard dipole, allows for dual-band operation by integrating a third element. This design effectively shortens the overall dipole length by 10 to 20 percent, simplifying antenna rotation and offering a compact footprint. KK4OBI's article delves into the operational principles, using a 6 and 10-meter Tri-pole as a primary example, and provides comprehensive instructions for constructing any Tri-pole antenna within the 6 to 15-meter range. Key to the Tri-pole's performance is its off-center feed, necessitating a common mode choke at the feed point for optimal tuning and reduced noise. The author outlines a methodical approach to determining element dimensions, starting with a vertical element frequency calculated as 0.47 times the sum of the desired upper and lower band frequencies. This calculation, along with K-values derived from trend lines, guides the initial lengths for the horizontal arms, demonstrating how a 10m-6m Tri-pole can achieve a total horizontal length 78% shorter than a conventional 10-meter dipole. Tuning and balancing are critical, with the article detailing adjustments to arm lengths and the vertical element to achieve balanced SWR values, as validated through 4NEC2 simulations. Radiation patterns are analyzed at various elevations, showing gains around 5.7 dBi and favorable take-off angles for DX contacts. Construction details specify aluminum tubing dimensions, U-bolts, and an SO-239 connector, emphasizing the importance of a ferrite-based choke for wideband operation.

September 24th 2012 till October 5th 2012 3D2C DX Pedition

The **Luis Trenker Award** is an amateur radio operating award established by the Amateur Radio Club Ladinia to honor the director and author Luis Trenker from Val Gardena, South Tyrol, Italy. To qualify for the award, HF stations must achieve five confirmed QSOs with each of five specific Alpine countries: Italy (with specific prefixes like I1, IK1, I2, I3, IN3, IW3, IV3), France, Germany (with DOKs A, C, T, U), Switzerland or Liechtenstein, and Austria (with prefixes OE2, OE3, OE6, OE7, OE8, OE9). A single QSO with a member of the Amateur Radio Club Ladinia can substitute for the five required Italian QSOs, with members' QSL cards bearing a special rubber stamp. VHF/UHF stations have a simpler requirement, needing only one confirmed QSO with each of the five Alpine countries. SWL stations are eligible under the same conditions as transmitting stations. All contacts must be valid after April 12, 1990. Applicants must submit a list of contacts, certified by two OMs or a club, to the Amateur Radio Club Ladinia in Ortisei, South Tyrol, Italy. The award manager is IN3PGS Karlheinz, and the club official is IW3AQL Luca.

Project by N9SSA

A Primer On Mics For Ham Radio. Difference between dynamic and condenser microphones, microphone plugs and differences in kind of microphones available on the market

Issued to any licensed radio-amateur or SWL who submits proof of radio contact with stations working form fortresses

A homemade j-pole antenna for six meters band, designed to work on local repeaters, and working on the 52-53 MHz. Includes a list of needed materials and detailed description on assembling the copper tubes used to build this antenna.

This is a Solid State Amplifier Project. It uses 4 MRF150 MosFet Power Transistors. The Power Supply Voltage is 50 VDC at 21.5 Amp. The max power available is 1,075 Watts. The Efficiency is about 65% +/- and runs Class AB Solid State.

An essential kite antenna plan for the top band, Antenna has been tested at half wave and quarter wave.

An article on origin and usage of the Decibel, that has always been a logarithmically based representation of a power ratio

Maual of the Ameritron ALS-600 power amplifier

28 Dec 05 - 4 Jan 06 Grand Cayman IOTA: NA 016 GL: EK99, Jamaica IOTA: NA097 GL: FK17

Antennas for the 1296 MHz based on the construction plans of some Yagis 35 elements by DL6WU, F9FT, DJ9YW. These antennas features a boom of about 3 m and gives a gain of about 17.8 dBd

The ICOM IC 7600 transceiver as successor of the IC 756 Pro3, resource page with many links and resources to the Icom top line HF transceiver

Exaustive review of the self-contained, top-performance HF/6m transceiver Icom IC-7700

This antenna is a classical antenna working on 7,10,14,18,50 MHz is implemented with three traps for 30, 17 and 6 meters

While there are quite a few standalone Morse Code or CW decoders out there, I wanted to tackle the problem myself and end up with both a great Arduino learning project and a decent portable decoder for when I'm out in the field operating QRP

Online antenna calculator for homemade double biquad antenna for UMTS 3G 4G WiMAX WiFi frequencies. Article includes also a simple biquad antenna for 4g

Fix VHF TVI problems usign a quarter wave stub filter

Design a parallel square stock balanced transmission line with this calculator.

Introduction to homebrewing antenna, for AM FM band reception

The Award is given for two-way QSO or SWL-report with Belarussian places who having old castles and palaces.

High Speed Multimedia (HSMM) radio, as introduced by John Champa, K8OCL, represents a significant advancement in amateur radio's digital capabilities, moving beyond traditional keyboard modes like packet radio. This initiative, driven by ARRL's Technology Task Force, focuses on developing high-speed digital radio networks capable of up to 20 megabits per second. HSMM primarily facilitates digital voice (DV) and digital video (ADV), enabling real-time video transmission from emergency scenes to an EOC without expensive ATV gear, often requiring only a laptop, a PCMCIA card, a digital camera, and a small antenna. The working group's initial efforts concentrate on cultivating microwave skills within the amateur community to build and support portable and fixed high-speed radio-based local networking, or **RLANs**. These networks prove invaluable for RACES and ARES organizations, as well as homeland security and other emergency communications. Field Day exercises and simulated emergency tests (SETs) are encouraged to hone skills in rapid site surveys and deploying broadband HSMM microwave radio networks, with examples like linking Field Day logging stations or antenna test results at the Midwest VHF-UHF Society Picnic 2003. Getting started with HSMM often involves adapting off-the-shelf **IEEE 802.11** (WiFi) equipment to comply with amateur radio regulations, typically operating in the 2.4 GHz ISM bands. While consumer WiFi gear has range limitations under Part 15 rules, proper setup under amateur regulations can extend coverage significantly, with test networks like the Hinternet achieving 5-15 mile ranges at 54 M bit/s using small mast-mounted dish antennas. Careful selection of equipment with external antenna ports, high transmit power, and low receive sensitivity is crucial, along with using low-loss coaxial cable like LMR-400 for optimal performance at these frequencies.

Antenna Analyzer plus 500 is a multifunctional measuring instrument, very useful for amateur radio activity. Its size allows you to easily take it for relocation as well. Frequency range: 100KHz - 500MHz. Access directly via WiFi. Includes a dual-channel signal generator

28.222mhz transmitting with 2 watts of power

What happens in impedance space when the various popular matching networks (antenna tuners) are adjusted

Modifications for Retevis RT3 / Tytera MD-380 includes Hardware Modifications, Codeplugs, Software / Firmware Modifications.

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.

Common mode currents are those currents that flow in the same direction on a wire bundle, as opposed to the currents that flow

This article is about replacing the LCD display in a Icom IC-756 classic. The displays in these radios have not been supported by Icom in several years.

Bird 4314 RF Power Meter Battery Replacement

The XV4-10 is a linear transverter for the 4m band to be used with a 10m transceiver. Input frequency 29-30 MHz, output frequency 69.5-70.5 MHz

These were some of the steps I took to setup my Allstar link node/server and some of the modifications that I did to it.

For every radio amateur who loves to travel by car, a mobile installation soon becomes a necessity. While in inhabited areas there is usually some coverage of VHF repeaters, in many other places VHF radios are useless. In these very places, HF can provide reliable contacts, and a lot of fun, from anywhere.

LA3ZA Unofficial Guide to Elecraft K2 Modifications

issued by the members of YO2KJI

The Vacuum Tube Page with a lot of stuff about tubes

DF0WD/DL4YHF's Longwave Overview details amateur radio operations on the 135.7 to 137.8 kHz segment in Germany. The author outlines the "inofficial" European band plan, specifying segments for QRSS, TX tests, beacons, conventional CW, and data modes. Early LF activities at DF0WD began with a 20-watt CW transmitter, later upgraded to a homemade linear transverter capable of 100 watts, driven by an Icom IC706 on 10.137 MHz. The station's antenna system includes a 200-meter wire, approximately 10 meters above ground, supported by football field light-masts. Despite its length, the antenna's efficiency is noted as very low due to the immense wavelength of about 2.2 km. The author's experience highlights the significant challenge of achieving effective radiated power (EIRP) on LF, estimating DF0WD's EIRP at around 80 milliwatts based on field strength measurements from PA0SE. DF0WD/DL4YHF has successfully worked numerous countries on 136 kHz CW, including DL, F, G, GI, GM, GU, GW, HB9, HB0, LX, OE, OH, OK, OM, ON, OZ, PA, and SM. The author also mentions ongoing efforts to log contacts with CT, EI, LA/LG, and to complete a two-way QSO with Italy, demonstrating persistent activity on this challenging band.