filter design

Cubical Quad Antenna Design  ^pop - By N6VNG, can be used to determine the element lengths and the gamma match values for different frequencies, includes link to excel files with formulas to dimension your quad antenna.

1270Mhz Yagi Antenna - Build your own antenna for the 23cm band ( 1250Mhz - 1280Mc ) using some aluminium and this simple design.

K-Com - comprehensive line of products for rejection of Radio Frequency Interference (RFI) to telephone equipment.

Q-PAR Microwave Antennas - The company (founded in 1973) excels in the research, design, development and manufacture of microwave antenna systems & components. Our range includes horn, reflector, sinuous, spiral, LPDA, helical antennas, etc; antenna positioners, and many bespoke components.

HD Communications - Rf Connectors,RF Amplifiers,RF Filters,HF cable and accesories. Tower hardware valves and tubes

Kiwa - Filters and performance upgrades for many receivers

Broadcast microwave services - Designs and manufactures a comprehensive line of microwave communications equipment for television broadcast, video, telemetry, and electronic surveillance applications.

Valve radios - Viking SW design and produce valve (tube) receivers for the ham and SWL.

Radio Adventures - Design and manufacturing of electronic components, kits, and accessories for the amateur and commercial communications. CMOS Keyers, W1AW receivers, PC borads kits

Bird Electronic - Design and manufacture of components, instruments and systems for RF power measurement.

PolarPlot - Freeware antenna software that lets you see what the polar diagram of your rotatable beam actually looks like where it is operating. With PolarPlot you can measure the polar diagram of the antenna and check for abnormalities - compare plots taken before and after changes to the design or location - check the -3dB beamwidth - look at the front to back ratio - see the size and position of the sidelobes.

Yagi Designer  ^pop - Program that produces antenna radiation patterns and graphs for SWR, forward gain, and F/B ratios

QARTest - Italian only contest logging software, designed for the ARI 40-80 contest.

Spectran - Program designed to do spectral analysis and real-time audio filtering on reception of audio signals for EME, VLF, SETI applications. Offer support for MTHELL, QRSS, DFCW, NDB, WSJT by I2PHD

VHF-DX - VHF-DX for Win95/98 is a VHF/UHF Logging Program specifically designed for 50MHz and above operation.

Int. Morse Code program information - This program is designed to help the beginner learn to receive and send the International Morse Code.

TTYlink - TTYLink is a freeware client chat telnet application designed for packet radio and available for Windows NT 4.0 and Windows 95/98.

Amplifier Simulation Program - ASP 4.0 - Design weak signal GaAs FET or bipolar PreAmps. Automatically designs for optimum gain, NF, VSWR or all.

KM5KG network designer - Windows98 Program for RF Design

PLL2 - 2nd Order phase locked loop design for passive and active circuits. Bode plot, step response, design parameters

Satfax - Satellite weather decoding software, designed for those weather monitors who use their ICOM R7000, ICOM R7100 or AOR 3000A

Tunekit - Filter Tuning Kit for Windows is a electronic filter synthesis program and a practical filter tuning aid for actually designing and building a working filter

TVI and BCI Filters - TVI and BCI bandpass and bandstop filters in SMD technique. Schematics and images.

Lowpass filter for 5MHz - The following lowpass filter was built using the tables in the arrl manual, it is a 5 section one and seems to work ok

KI5YN QLF Filter - The QLF filter is a microprocessor based interface designed to go between a standard Morse code key and a radio transmitter