low pass filter 144mhz

Constructing a LowFER Antenna - This article describes the antenna for Low Frequency Beacon. It originally appeared in the "Lowdown" for Oct. 1999.

80M Vertical antenna with capacitance hat  ^pop - Simple wire antenna cheap to make, using readily available materials, Low angle radiation, with rejection of high angle signals Wide bandwidth, with resonance at the 80M DX window (3.790-3.800 MHz); and Maximum height is 40 feet

Antenna Height Theory - Antenna mounting height, the higher the better? Learn how radiation pattern change, and decide if you need an higher or a lower angle for your dx needs.

New HF antenna HB9ABX  ^{updated  pop} - A new, revolutionary design allows the construction of small HF antennas, which provide the same efficiency as large antennas. This antenna can be built for all HF bands, from 10 to 80 m.

K5ZD contest audio recordings - Have you ever wanted to listen in on a serious SO2R DX contest effort? hear what the low bands sound like from New England? enjoy a contest without having access to a radio? This is your chance!

DCI Digital Communications Inc. - Filters, Duplexers, Combiners Bi-Directional Amps

SoftRock-40 - The SoftRock-40 is a small, low-cost, good-performing "software defined radio" receiver that plugs into a computer USB port and delivers I-Q audio signals to the computer's sound card. It was designed by Tony Parks, KB9YIG and Bill Tracey, KD5TFD as an "SDR sampler project" for hams everywhere to easily try out software defined radio.

Telewave - Telewave's innovative engineering produces the industry's toughest antenna systems. Yagi, Fiberglass Collinear, and Dipole models are available from 66-2500 MHz. Wattmeters, test equipment,rf power meters, duplexers, filters and cavities, transmitters combiners

How Radio Works - Excellent slides explaining radio and radiowaves generation basics

Great Circles & QRA Locator Online - Interactive great circles and QRA Locator map

Really Low Frequency Operating - The world below 500 kHz (The wavelength is 1500 meters or just about a mile) has a number of interesting listening and communications opportunities with possibly more to come.

KØBG's ham radio mobile operator web site - This site is dedicated to mobile amateur radio operators, old and new alike. Whether you are into HF, or VHF operation, I trust the information presented will increase your enjoyment of our great hobby. With safety as a byword, there are articles on amplifiers, antennas, bonding, impedance matching, installing hardware, mobile equipment, noise and RFI abatement, wiring, and much more. I do my best to keep these articles up to date, and easy to follow.

ON7YD ARDF pages - Includes some interesting projects for low power ARDF transmitters

A low power 3.5MHz ARDF transmitter - This low power transmitter is developed for ARDF exercising purposes but of course can be used as super QRP transmitter either. With 1 or 2 meter wire as antenna and a ARDF receiver with ferrite-rod antenna the range is about 100m but with better antennas and a 'real' receiver the range is probably much larger.

HF Antennas for restricted space - Arrl document about invisible antennas and indoor systems. It is important to consider that few compromise antennas are capable of delivering the performance one can expect from the full-size variety. But the patient and skillful operator can often do as well as some fellows who are equipped with high power and full-size antennas. The "cliff-dweller" may not be able to "bore a hole" in the band as often, and as easily, but DX can be worked successfully when band conditions are suitable.

Isotron antenna manulas - From this page you can download the following manuals, in Adobe Acrobat format .pdf, 40 Meter Isotron, 80 Meter Isotron

APRS-Beacon - The purpose of the APRS-Beacon is to provide simple APRS-compatible position beacons for up to three Objects. It is designed to 'stand alone' and does not monitor other traffic on the frequency. It can use a single-port TNC (in 'native' mode), a single- or dual-port TNC in Kiss mode or the AGW Packet Engine in order to transmit on up to four radio ports.(When running with AGWPE, APRS-Beacon will also work with Windows 2000)

HamCalc v1.3  ^pop - By G4VWL, HamCalc is collection of calculators for radio amateurs: Antenna ERP calculations. Attenuators. Audio Filter design.Coil Winding. Decibels. Great Circles map and calculator HF Filters HF Traps Metric conversions OP Amps QRA Locator to Latitude/Longitude (and back) Radio Horizon calculator Resonance Satellite orbit calculator Timer calculations (555 timer)Zener Diode calculations

SmartSmith - A smarter version of the Smith Chart program. It allows you to dynamically generate impedance point plots as you configure each design element of an impedance matching network. Has an extensive Help file with a Wizard that tells you what steps to take in designing a matching network for a given load impedance. Complete Windows installation kit by w9dmk

UALOG, YVLOG, SQ, AutoCQ - UALOG, russian logbook, YVLOG log program for icon 756 radios, SQ echo repeater and DSP Filter for your radio

MorseGen v1.2 - MorseGen converts text into a WAVE file of Morse code. The Tone and Speed are adjustable and the WAVE file can be repeated at a pre-set interval allowing it to be used as a CW Ident for amateur radio applications which require it.

Morse Maker - MorseMaker is an up-to-date replacement for the Morse Machine shown further down this page. It has been re-written using a different programming language and is now entirely 'stand-alone' requiring no run-time support files. This version also works with Windows XP and can use the soundcard but please note that, unlike its predecessor, it does not split the alphabet into smaller 'learning' blocks and does not incorporate the Morse reader.

Shortwave Log (SWLog) - Shortwave Log, SWLog is a comprehensive logging and radio control program. While designed for shortwave and mediumwave listening, the program is quite adept when listening to longwave, utility, or amateur radio. Support Icom Drake TenTec Yaesu JRC and lowe receivers.

GNU Radio - GNU FSF Project - GNU Radio is a collection of software that when combined with minimal hardware, allows the construction of radios where the actual waveforms transmitted and received are defined by software

GnuRadio: Universal Software Radio Peripheral - The UniversalSoftwareRadioPeripheral (USRP) is a low-cost, high speed implementation of GnuRadioHardware, developed by a team led by MattEttus