filter design

2 Meter 10 Element Quagi Antenna - This antenna was designed by N6JSX Kuby for Transmitter hiding. Fitting the requirements of directionality, high gain, and portability. This antenna was derived from the ARRL Handbook information on Quagi's and Yagi's; in the absence of two meter Quagi information, UHF Quagi dimensions were scaled into 146 MHz use.

Quagi and Yagi on 2 Meters - Designing quagi and yagi antennas on 2 Meters, some preliminary notes by Cebik, W4RNL

Six Meter Wavelength Band Antennas - Why 6 meter hams design the best antennas

Choke balun  ^pop - Essentially, a choke balun is designed to 'divorce' your antenna from the feed line. if your feed line is coaxial cable then you don't want it to be part of your antenna. you want to be able to deliver all your power to the radiator itself, i.e. 'the antenna'. a choke balun does this admirably

The J-pole Antenna Revisited Yet Again - The dynamics of antenna design

Loop Antenna Design - Full-wave loops are very popular antennas. They are especially useful on 80 and 40 meters where they perform well at modest heights

HF Mobile Antenna HB9ABX - Most efficient hf mobile antenna, This mobile antenna is designed for all HF bands from 10 to 80 meters an proved to be very efficient in my travels in South America on 15 and 20m for contacts to Europe and within South America.

An automatically tuned 7-30MHz mobile antenna - This is a base-loaded vertical antenna that mounts on the car's roof. The loading coil is designed as a variable inductor, with a three-legged chariot that travels up and down inside the coil, with grooved brass wheels running on the coil turns, and driven by a slotted rotor tube.

Quagi Designer - Quagi antenna design, this little windows application let you calculate dimensions of elements and spacing of a quagi antenna. Freeware by VE3SQB

2m Quagi Antenna plan  ^updated - A design of a 2 m quagi antenna by TA2IB

K5OE, 70 cm Quagi Antenna - An AO-10 antenna by K5OE, this design is optimized for 436.8 mHz with a 50 Ohm feed

CSVHFS Antenna Gain Measurements - The Central States VHF Society has conducted Antenna Gain Measurements since its inception in 1967. Comparisons between commercial and homebrew antennas, between different homebrew designs, and between different commercial designs. Mostly VHF UHF and up antennas.

Crank-up Tilt-over Tower  ^pop - A home made tower, with project design and pictures

Coaxial Traps for multiband antennas - A new perspective on the analysis and design of this popular antenna element. By Karl-Otto Müller, DG1MFT

2.4GHz Cubic Quad Antenna  ^pop - The Cubic Quad antenna is a commonly homemade antenna in the range of about 150 odd MHz. Our little project was to design one of these for use in the 2.4GHz range for 802.11 wireless LANs.

eham DX Spots - DX Spots web cluster interface with filtering features available to eham subscribers

Tennamast - Tennamast design and manufacture a wide range of fabricated metal goods, Antenna masts, Wind-sock masts, and masts for holding such systems as CCTV, Loudspeakers, Lighting units

Heinz Bolli AG - Antenna tuners, components, filters and baluns manufacturer based in germany

Tarheel Antennas - Our motorized antennas and stainless steel mounts are designed with the most avid HAM radio operator in mind, as well as commercial applications. They are made with the best materials and top of the line workmanship. Antenna mounts

Communication Concepts, Inc. - Provide components to the amateur who wants to construct their own gear and to the professional who wants to save money and time in prototyping their circuit design, Filters, HF Amplifiers, Splitter Combiners, VHF Amplifiers, ATV

International Crystal Manufacturing Company - International crystal manufacturing provides quartz crystals, oscillators, precision crystals, filters, tcxos / vctcxos, qcm crystals, and other frequency control products. read details about our crystals and frequency control products and services.

microHAM - Supply high quality accessories for your ham shack, including Band Decoders, various types of Antenna Switches, Antenna Stacking devices, special devices designed for the SO2R operator, USB Interfaces, Digital Mode Interfaces, Keyers and many others

F5VLB amateur radio astronomy station Priority listing - F5VLB and EA4EOZ have designed a small but powerful system using satfinder and standard LNB to make radioastronomy. A step by step descritpion for the novice about radioastronomy, VLB and listening to echo of meteorite.

Technical resources for design engineers using batteries and power supplies. - Resources for custom battery chargers and power supplies from powerstream

Avoid pitfalls when recharging batteries to ensure long life - Portable design - avoid pitfalls when recharging batteries to ensure long life - secondary batteries can be simple devices, but improper charging can be devastating to the user experience.