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Understanding current in loading coils

How to make an effective RF Choke. The coiled coax choke is the easiest to make but also the least effective. This article includes some general guidelines for winding coax chokes on a 10cm PVC pipe using RG-58 or RG-213 coax cable.

Tips on winding wire coils used as inductive loads, traps, band-pass filters, are implemented in a number of amateur radio projects especially antenna projects

Skin effect and proximity effect on making coils with stranded wire. An interesting comparison on making coils.

Communication Coil, Inc. designs and produces custom, high reliability Filter Networks, RF Coils, Chokes, Inductors, Baluns, Toroids and Power Magnetics for communications

winding coils for construction project

Maker of filters, oscillators, cristals Coils, Toroidal Inductions, Solenoids, Bifilar wound Solenoids, Trifilar Solenoids and Transformers Located in Kansas City, Missouri

A vertical antenna project for the 7MHz made with some spare parts. Based on a broken 20 foot fishing pole, it is based on a good ground system made with radials and a capacitive hat done to increase the global radiation resistance of the antenna. A custom loading coil is also included in this project to perfectly tune the antenna to the CW portion of the 40 meters band.

Amateur Radio 40m 20m 15m Half Wave Fan dipole antenna project with part list, pictures and drawing. Includes the option to expand the antenna to cover the 80 meters band

Originally eveloped by I1FLC, uses seven plug in coils covering 3.0 to 30Mhz in a Colpitts oscillator circuit.

The Vertical Buddi Beam on 20m using no Coils. n this article I am going to describe a totally new way to construct and use a very old design the two element Yagi antenna. Unlike the traditional Yagi this design does not require a Tower or a boom, it is 100 percent portable and most important high- performance and easy to assemble using standard Buddipole components.

How can the current "flowing" out of the top of a mobile loading coil be greater than the current "flowing" into the bottom of the coil?

Coil winding on 4 inch PVC tubing with home-made tooling.

This unit uses four capacitors, only two of which are variables, and a single tapped coil. It is built in a die-cast box, and has been tested up to 80W input power on 70MHz by G4CJZ

Comment on W5DXP 2011 coil measurement experiment

Manufacturer of transformers, inductors coils and chokes. Custom winding, EMI / RFI Filters, Antenna Windings on ferrite rod, Antenna Winding on phenolic. Any antenna coil designs.

Coil Q Measurements - With a special focus on wet coils.

While intended mainly for antenna loading coils, this article also applies to other resonant systems, such as amplifier tank circuits.

A very popular method of making a short dipoles resonate at a given frequency. This type of antenna is suitable for single band, narrow bandwidth use.

The program can be used to calculate inductors (coils) and their number of turns on ferrite cores, ferrite shells and air coils. These can be used for baluns, Ununs, bandpass filters, low pass filters, resonant circuits, and more. The technical specifications of the cores are already integrated in the program. Application is free and runs on Windows 32 bit versions only. To make it run on Windows 10 64 bit need to be unzipped in a single folder.

Article describes a circuit that accelerates the coil of DC relays by momentarily doubling their voltage.

Online calculator for Input coil data, LC Resonant Frequency and L match

About experiments and measurements on loading coils using net standing wave current

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.

The alabama historical radio society - come visit our website and museum where we have a large collection of antique radios. our club does coil winding, has a large library, and a wealth of knowledge in our members.

There is a specific procedure which must be followed if proper adjustment of a shunt matching coil is to be achieved.

The webpage discusses metal fatigue in antenna elements for radio amateurs, offering construction tips and techniques. It covers theory, tricks, and the use of baluns and coils.

Select the toroid by material type and dimension of the toroid, the desired inductance and you will get the numbers of turns

Experimenting a 20 40 meter short coil loaded dipole antenna with the goal to keep the total length under 40 feet so that the dipole can be mounted on two 20 foot fiberglass pole to make a 20/40 meter rotatable dipole.

Rewinding solenoid coils and how to article

A dual band dipole antenna for 40 and 80 meters band. Total lenght of 26 meters, foreseen two coils at aprox 11 meters distance from center feed.

This online calculator will give as output the Inductance L of a coil, including the total lenght of the wire needed to wound the coil. As input, requires the Diameter, number of turns, wire diameter and turn spacing

This calculator ask as input diameter, lenght turn and frequencu and will return L and Q

You can shorten a vertical antenna by using a loading coil. This online calculator tells you how the amout of inductance your loading coil will need to have.

How to configure the ICOM IC 7100 to correctly work with FLDIGI on Windows 7 64 Bit. How install USB drivers and how to properly set COM ports and how to configure CI-V

Noble Enterprises, Heli-coil Helicoil, Helicoil Insert, Helicoil Inserts, Inserts, Cutting Tools, Thread Cutting Tap, Thread Cutting Tools, Machine Tap,

This article dives into a budget-friendly, DIY antenna option - the multiband half wave end-fed antenna (HWEF). Forget expensive radials; this design uses just wire and a transformer. While the 2012 approach might be dated, it provides a solid foundation for understanding HWEF concepts. Explore how different coil setups can target specific bands (40m, 20m, 10m) for optimal radio communication.

Free ham radio utilities written in LabVIEW includes Open Wire Calculator, Dipole Peak/Null Angle Calculator, a Coil-Shortened Antenna Calculator ad interesting Round Coil Inductance Calculator and a Skyloop Antenna Calculator

The antenna handles 250 watts and covers 40 through 10 meters, with an optional add on coil for 80 and 60 meters. The author in this pages includes an interesting video in which describes the antenna setup, and the importance of the shunting coil on lower bands like 40 and 80 meters. SWR curves diagrams are also included and demonstrate the influence on resonating frequency of the shunting coil.

An interesting article on end fed half-wave wire antennas with a couple of original experiments. Author illustrate the role of the QRP matchbox, and a 40/20 meter antenna with a center stub making it a large bandwidth antenna for 40 and 20. Includes also an 80/40 end fed with the typical coil to make it available on 80 merts band.

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

Calculate inductance online, with the cylindrical Coil Inductor Design Equations Formulas Calculator

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

Repairing a Cushcraft R7000 antenna featuring several problems, mostly concerning coils and the insulating parts of the antenna.

Calculates inductance and Q for single-layer coils made of solid or Litz wire. Uses U.S. or metric dimensions. Can automatically maximize Q. Includes accuracy data. Runs in Windows.

Electronic Products Design Inc based in North Carolina, offers you custom design of transformers, coils, and telemetry control systems.

How many times have you heard the advice to coil a few turns of coax at the antenna end to form a choke. How to find out if your common mode current choke really works

The collinear J-Pole, often known as the Super-J, does improve the behavior over a regular J-Pole. there is an advantage when vertically combining 1/2 radiating sections to have a bit of separation between the half-wave end points. Get 0.8 dB more gain out of the trusty Super-J by replacing the traditional phasing stub with a long coil.

With this antenna the coverage is 80,40,20,15 and 10 meter band without any antenna tuner and the average SWR is below 1.2 on phone bands. The total antenna lenght is about 23 meters , with one 20.4 meters long segment from the 1:49 transformer to the 110uh coil and about 2.2 meters long segment from the coil to the insulator.

This antenna just requires about 24m of free space instead of 41m that a normal half wave 80m antenna needs to hang up. The so called loaded dipole uses a coil in every dipole arm to electrically lengthen the mechanical too short dipole arms. Every coil has an inductivity of 120 microHenry.