emi filter

3 Elements on 40 Meters - The inverted "U" 3 elements on 40 meters by ik2egl

2 elements U Beam for 80 meters - An U Beam antenna for 80 meters band by ik2egl

QRP Antenna 80-40-20-15 End Fed Antenna - A long wire antenna that will load up on 80, 40, 20 & 15 meters without an antenna tuner and without balun coils

Vertical amtennas among the trees - Experiments on vertical antennas among the trees by ik2egl

Automatic SWR meter  ^updated - Automatic SWR meter and semi-automatic tuning unit by F1FRV

Shortest Vanity Callsigns  ^updated - This is a service for finding the shortest available vanity callsign in your amateur radio class. It filter through all possible callsigns and provide just the unused ones weighted by their length in morse code or their actual number of letters.

Chile Awards - More chielean awards including the Pablo Neruda Award

The Renfrew CountyAmateur Radio Club - The Renfrew County Amateur Radio Club is located in the County of Renfrew in the province of Ontario, Canada.

K5TIT - The Texas Interconnect Team - One of the premier D-Star systems in the USA

Yuma Hamfest & Electronics Expo - Yuma County Fairgrounds, Yuma AZ. On site RV/camping facilities. Seminars, Exams, Tailgating.

Accute Micro - China supplier of ceramic bandpass filters in standard resonator sizes of 2~6mm , 8mm , 10mm and 12mm with freqency from 400Mhz~4Ghz and sections 2~10

Duplexers for Ham Radio repeaters - We produce duplex filters and antennas for 2m,70 cm and 23 cm repeaters.

I6HWD Morse Key Collection - A collection of morse code keys including verticals, semi atumatic, automatic and other accessories

Sporadic-E propagation at VHF - This review of progress and future Prospects provides a practical guide for effective use of VHF sporadic-E propagation. By Emil Pocock, W3EP.

Garth RF Filters - ATV Filters, RF filters dealer

TubesWorld - Dealer for valves and semiconductors

SWL DX Cluster - Web cluster for swl's. With many features, including filters, search, SWL Database, lookups

EIS Spectrum Analyser - Freeware program for analysis and simulation of impedance spectra

Batteries and QRP - Thanks to the popularity of cell phones, laptops and other personal electronic devices, the battery industry has been market-driven to produce higher capacity batteries in lighter weights than previously possible with yesterday's chemistries.As a result, a wide variety of battery types are available to the outdoor QRP operator.

500 KHz Low Pass Filter - This article describes a shielded low pass filter with a cut off frequency of about 500 KHz. It is built with components suitable for receiving, and was designed to use in front of a low frequency receiver for LOWFER work.

1.8-54 Mhz Low pass filter - An easy to make HF low pass filter form high power by k8cu

Homebrew a CW Filter - An home-brewed morse code CW filter with a central frequency of 800hz and a variable bandwidth from 230hz to 26hz by F5RDH in french.

Interdigital bandpass filter designer - Fill out the form to design a bandpass filter as described in the January 1985 issue of Ham Radio Magazine. These filters are generally limited to frequencies above 200 MHZ because their size is slightly longer than 1/4 wavelength

VHF signal generator - a simple VHF signal generator in order to measure the characteristic of low pass filter.

A single board no tuning 23 cm transverter - This transverter uses bandpass filtering with printed hair-pin filters. By KK7B