astro

astro

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• 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.
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• SWR: Maximum allowable VSWR - VSWR (voltage-standing-wave-ratio) represents the degree with which an antenna is "matched" to the system impedance. Most modern antennas do not require any tuning for optimum performance. VSWR is one of the easiest parameters to measure and VSWR meters are becoming very popular antenna installation tools
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• G5RV multi-band antenna - Multi-band centre-fed antenna capable of very efficient operation on all HF bands, specifically designed with dimensions which allow it to be installed in gardens and other open spaces which accommodate a reasonably-straight run of 31.1m (102 ft) for the flat-top standard model.
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• G5RV multi-band antenna construction guide  ^pop - Excellent guide to build your own G5RV antenna by Lombry
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• 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
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• Wellbrook ALA 1530 active magnetic loop review - Interesting review about active magnetic loop antenna Wellbrook ALA 1530 and 330S by ON4SKY
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• Antenna Selection Made Easy - This page will help you answer important questions about antenna selection before you talk to a supplier. After reading this paper, you should be able to better determine the most important parameters you need to know for your antenna selection criteria.
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• QSL and green stamps by ON4SKY - What become our QSL once sent ? QSL routes, IRC and green stamps, the best and worst practices.
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• All about Lightning protection - Thierry LOMBRY, ON4SKY, gives advice to amateurs about lightning protection of an hamshack, including pictures and links.
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• How to become an amateur radio - How to become an amateur radio ? by ON4SKY Review of general conditions to get licensed, examinations, regulation, CW, foreign calls, and more
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• Amatorska Radioastronomia - Amateur Radioastronomy in Poland
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• Clusters and Packet Radio - Introduction to the use of clusters and Packet Radio, hardware, settings and commands by ON4SKY
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• Meteor and Colorgramme - FREE specialized software in the detection and registration of echoes radio products by meteors shower, falling star, at the time of their gone in atmospheric. They are destined to all possessors of a radio and a computer, interested parties by this simple technique of radioastronomy.
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• Home Planet Release 3.1 - Comprehensive astronomy / space / satellite-tracking package for Microsoft Windows 95/98/Me and Windows NT 4.0/2000/XP
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• Satbuster - SATBUSTER for Windows is especially designed for satellite visual observers and trackers. Its users, mainly amateur astronomers and radio amateurs, appreciate both the accuracy and the simple to use graphical interface.The software is aimed to hobbysts. However a growing number of plain folks are starting to use this tool to recognize and look at the International Space Station and the Space Shuttle during its missions too
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• Ballistic simulator Orbit - Ballistic simulator "Orbit" allows the physical principles of the motion in the gravitational field of the Earth to be demonstrated and learned. You can calculate with this program the ballistic trajectories of the thrown bodies and orbits of spacecrafts and visualize the astroballistic situation on the flat map of the world and on the rotating globe in the real time
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• GorbTrack - GorbTrack or Geostationary Orbit Tracker is a freeware program intended to be an aid in finding geostationary satellites. It produces output helpful in aiming dishes for receiving television broadcast satellites. The program also displays several astronomical values like the positions of the sun and moon
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• RF Coaxial Connectors - RF coax(ial) connectors are a vital link in the radio spectrum. Coax connectors are often used to interface two units such as the antenna to a transmission line, a receiver or a transmitter. The proper choice of a coax connector will facilitate this interface.
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• About Lightning Protection - What You Should Know About Lightning Protection by Joseph H. Reisert
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• Powerline communications - Europeam perspective on BPL PLC
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