call sign lookup

Transmission Lines - Whenever you choose a coax feedline, the frequency of operation is a very important consideration. Over the operating bandwidth of the coax the VSWR is low, typically 1.2:1 or better. Insertion loss is also an important parameter. It is usually specified in dB/foot and is a linear relationship.

Yagi Element Mounting Considerations - One of the most important considerations when designing and building a Yagi antenna is the method used to attach the elements to a boom. This is true because the boom influences the electrical length of the elements. In this article JH Reisert explain with drawings techniques on mounting yagi antenna elements to a boom

Antennas for 136kHz - A very long and exaustive documentation on building antennas for 136 khz. Includes links to antenna design software for longwave

VHF/UHF Yagi Antenna Design  ^{updated  pop} - Design your vhf yagi antenna online, a JavaScript enhanced web page that implements the design of an antenna in the VHF, UHF by K7MEM

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.

Contest LogChecker - Contest LogChecker is a set of contest tools for Microsoft Windows, combining advanced text editing with keyword highlighted, and the ease and flexibility of import, export, statistics and charting utilities. With LogChecker you can edit, fill in the log, check Cabrillo Format and Header, convert files from the most popular logging software to Cabrillo, print customizable files, calculate statistics and export logs to RTF, PDF or HTML for publishing. You can examine a log in many different ways by highly interactive methods. LogChecker includes a Master Callsign Database tool for managing databases, which have been generated from actual contest logs. Commercial

Italian Callbook - CallBook OnLine - this callbook includes data from over 50000 italian radio amateurs

VU2LFA ham radio in india - This site is basically for the begeners (SWL) of india. This site is supporting to digital communication for hams also.

Micro Coax Priority listing - Serving the defense, telecommunications and test measurement marketplace.

Antenna Noise and Signal Cancelling at LF - The fact that the phasing between a wanted signal and an unwanted signal can be different on different antennas is put to advantage. With this condition, the unwanted signal can be cancelled out by controlling amplitude and phase. The heart of the system is some form of phase control circuitry.

Frequency Calibration for Weak Signal Work - Accurate calibration of your receiver and sound card is necessary for good results with the weak signal modes in use at LF. Modern receivers with master oscillators that are synthesized to provide all conversion frequencies greatly simplify the process. This article describes a method of making the necessary measurements and adjustments to an ICOM R75 receiver and a sound card, using the ARGO software

Transmitter hunting, in San Francisco Priority listing - Amateur radio direction finding, transmitter hunting. triangulating a radio signal direction and plotting its bearing on a map. hunters use doppler systems for tracking hidden transmitters

ESA Portal - Calling all radio amateurs Priority listing - Radio amateurs worldwide are being asked to help collect data from the student-built SSETI Express satellite, due to be placed in orbit on 27 September. To encourage them, ESA’s Education department has organised two competitions and is supplying free downloadable software.

Space Weather Education - Special space weather course designed to teach individuals without any background how to predict space weather

WD6CNF DSP Filter - Audio Digital Filter, two bandpass filters, three notch filters, two noise filters graphical setting of filter center frequency and bandwidth Drag vertical lines on top of signal, Microphone input, speaker output Mono, 5 kHz bandwidth

Phase 3D (AO-40) Decoder - This program demodulates the telemetry data signal transmitted by the AO-40 satellite (aka Phase III-D) using the PC sound card

Konfabulator - DX Cluster Priority listing - Freeware windows XP and MacOSX konfabulator widget dedicated to Amateur radio operators, is an easy interface to DX-Summit the ham-radio DX Cluster. DX cluster spots represents live ham radio communication connections, and are an invaluable resource for amateur radio operators. Users can choose Bands or operating modes like digital emissions, QRP IOTA and more. Spots are refreshed automatically and refresh rate can be set by users, with a minimum of 100 seconds.

Online Callbook for Internet Explorer - The Online Callbook for Internet Explorer makes it easy to find QSL information from the most popular HAM-radio web sites, such as QRZ.COM, ARRL.ORG, RAC.CA, QRZ.RU, BUCK.COM and OCTAVIA.COM,

QuikPSK - Supports both PSK31 and PSK63, sends and receives color thumbnail portraits by PSK63, displays 24 PSK63 channels simultaneously, and features semi-automatic mode selection between PSK63 and PSK31. Merely left-click on a PSK63 signal to copy, or right-click on a PSK31 signal to copy.

Packet Terminal Interface - Simple Windows based TNC interface program Designed for ARES operation, simple operator interface to connect and perform communication functions, control operator programs screens before operations Both receive and transmit screens Simple Windows based TNC interface program Designed for ARES operation Simple operator interface to connect and perform communication functions Control operator programs screens before operations Both receive and transmit screens

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.

DDS VFO Controller - Control the NJQRP DDS Daughtercard from your PC. The DDS Controller has eight user programmable configurations. Each of the eight configurations have twenty memory cells for saving and recalling frequencies

HamView - A freeware program to dig out weak signals buried in noise, functionally similar to the excellent FFTDSP of AF9Y, but with the added bonus of real time audio filtering of the incoming signals. Just point and click with the mouse, and the selected signal will stand out from the QRM and noise.

QRM and noise reduction Priority listing - You will find on these pages my experiences and results on antennas and local/non-local QRM/noise reduction. Using a broadband vertical active magnetic loop and a home made / designed broadband amplifier. Two vertical magnetic Alford loops are used in an array. Analog and Digital Signal Processing and a dual phase coherent Software Defined Radio (SDR) are used. By PA0SIM

A 80/40m Direct Conversion HF Receiver with DDS VFO - Juha (OH2NLT) and Matti (OH7SV) have designed JUMA-RX1, an award winning 80/40m direct conversion HF receiver with highly accurate direct digital synthesis VFO. The receiver is very compact, because it constructed using surface mount components. No coils need to be wound to construct this receiver!