- 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.
A two dollar helical hf portable antennapop
- Here’s an easily transportable vertical antenna for 20 meters collapsible to 4 feet that costs about $2.00 to make.
This was created as a fun project to demonstrate how to enjoy operating HF in the field with a home-made portable antenna without spending a ton of money.
Bev AH6NF (YL) made this antenna, tuned and ready to operate in less than one hour
Antenna Polarization notes
- Antenna polarization is a very important consideration when choosing and installing an antenna. Most communications systems use either vertical, horizontal or circular polarization. Knowing the difference between polarizations and how to maximize their benefit is very important to the antenna user.
PJ2T - Caribbean Contesting Consortium
- The Caribbean Contesting Consortium is a contest club dedicated to fun, international friendship, and advancement of the contesting art through superior operating technique and maximum application of technology.
Newark Amateur Radio Association
- The mission of this Association is to foster and promote the hobby of Amateur Radio, to provide repeater systems for the Amateur Radio community, to provide public service and emergency communications when needed, to provide education for licensing, and to provide a forum for members to meet and exchange information, share experiences, and socialize with one another.
Zanesville Amateur Radio ClubPriority listing
- The Zanesville Amateur Radio Club (ZARC) is an association for the purpose of providing amateur radio communications in times of emergency: installing, maintaining, and operating a 2-meter repeater and club radio shack, and promoting amateur radio in general.
KVK Antenna Systems
- The manufacturer of the NuBeam, Vipole, and the multi-band Quad-Folded-Dipole (or QFD for short) antenna. Also have a unique multiband vertical which can combine operation on multiple HF frequencies as well as provide high gain on 50, 144 and 438MHz in a single antenna.
RACOM - Radio modems
- RACOM is a Czech company specialized in design and production of radio modems and other devices for wireless data networks for radio channels from 140 to 900 MHz. RACOM radio data networks are suitable for data transfer in telemetry & SCADA applications, transaction networks, security systems, IP networks and firts of all mobile tracking and fleet management.
FlexRadio Systems - Software Defined Radios
- FlexRadio Systems delivers the first truly open source Software Defined Radio transceiver for Amateur Radio use. Receive Only versions are also available for non Amateur Radio applications. Read the SDR Articles and the SDR-1000 Product Information.
- 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
About digital modes
- The digital modes provide a wonderful opportunity for those of us who would like to work on the HF bands but find CW too difficult and SSB phone prohibitive because of interference problems. The digital modes are easy to set up and get operating, require low power and a narrow band.
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.
W2LJ's QRP Amateur Radio
- Dedicated to QRP, Morse Code and operating in the great outdoors, this pages contains a description of a CW QRP portable set, also some stuff on the Buddipole and PAC-12 antenna systems.
Thunt.org : transmitter hunting
- Amateur radio direction finding, transmitter hunting web site from San Francisco. Triangulating a radio signal direction and plotting its bearing on a map. Hunters use doppler systems for tracking hidden transmitters anywhere in the san francisco bay area, fremont california
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.
Automatic Identification Systems (AIS)
- Automatic identification systems (AISs) are designed to be capable of providing information about the ship to other ships and to coastal authorities automatically.
ComTekk Tone Generator
- ComTekk Software Tone generator for 2-way radio signaling. Use sound card to generate CTCSS, DTMF, tone remote, ANI and more. Synthesizer for simulation and testing of 2-way radio systems, repeaters, remote control, ANI, Paging and more
CQiNet, linking Ham Radio
- CQiNet is a family of programs that combine Ham Radio with the Internet using Voice over IP (VoIP) technology. Two programs are currently in the family, "theBridge" and echoLinux.
Thebridge is a iLink/EchoLink compatable conference bridge that runs under various versions of Unix as well as Windows.
EchoLinux is a EchoLink client program for the Linux operating system.
Antenna elevator system for amateur satellitespop
- Smart homebrew antenna-ELEVATOR system with linear actuator. The actuator is a cheap and heavy tool with high enough torque, ideal for elevation systems, but in practice it needs quite an effort in order to operate correctly in your homebrew antenna system. This page inform you of the actuator's secrets.