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Antennas : 2M

• Budget-Friendly 5-Element Quad Antenna Design - Constructing a 5-element quad antenna, the author aimed for low cost and simplicity, resulting in an effective design with 11 dBi gain and SWR of 2:1 or better across the 2-meter band. Using wood and dowels, the antenna costs under $8 and takes less than two hours to build with basic tools. The model predicts excellent performance, confirmed by ARRL Lab measurements. Practical field results demonstrate improved communication, even in simplex mode.
  [ Hits: 118 | Votes: 1 | Rating: 7 ]

• Do not wind chokes on red toroids! - I happened to stumble across some antenna projects showing common mode chokes 1:1 baluns made of some turns of coax wound on T200-2 iron powder toroids.
  [ Hits: 187 | Votes: 0 | Rating: 0 ]

• Double T Bar Verticals - Double T Bar Vertical antenna are vertical antenna with cross bars on the top and bottom. These crossbars provide capacitance loading thus reducing the size of the antenna
  [ Hits: 858 | Votes: 3 | Rating: 6 ]

• Amateur Radio Emergency Service - "ARES trains and organizes Hams to provide emergency communications to ""Served Agencies"" such as FEMA, National Weather Service, Red Cross, Salvation Army, Hospitals, and others. This site describes ARES goals and methods and structure."
  [ Hits: 5949 | Votes: 6 | Rating: 8.83 ]
• Sarasota County Auxiliary Communications Service, - The Sarasota County Auxiliary Communications Service, ACS, (Formerly Sarasota County ARES, RACES) is a program created to provide emergency communications for the Red Cross and Sarasota County Emergency Management.
  [ Hits: 589 | Votes: 5 | Rating: 7.8 ]

• Tuolumne County Amateur Radio Electronics Society Ham Radio Club - TCARES - The TCARES membership provides communications assistance with fires, floods, search & rescue, and health & welfare message assistance to the Red Cross, without pay, using their own equipment, usually in twelve hour shifts.
  [ Hits: 167 | Votes: 0 | Rating: 0 ]

• ICRCweb - Insurance City Repeater Club - The Insurance city repeater club operates out of central connecticut and works closes with the american red cross
  [ Hits: 574 | Votes: 6 | Rating: 10 ]

• GRARC Ham Radio club - The club is located in Dubuque Iowa, on the banks of the Mississippi River.We are active in the American Red Cross and various community events.
  [ Hits: 780 | Votes: 6 | Rating: 8.33 ]

• ECS ARC - Emergency Communications Service ARC was formed and established in 1964, at the Queens Chapter of the American Red Cross
  [ Hits: 565 | Votes: 1 | Rating: 1 ]

• The Transatlantic Tests - From 1921 to 1924, radio amateurs experimented with transmitting across the Atlantic. Everyday Engineering magazine organized the first sending test with English amateurs prepared to listen for signals from the US
  [ Hits: 343 | Votes: 0 | Rating: 0 ]

• HamThreads - Custom embroidered hats, shirts and jackets to Ham Radio Operators small businesses, ARES, ARRL and RACES clubs across America.
  [ Hits: 191 | Votes: 0 | Rating: 0 ]

• PCB gEDA - PCB is an interactive printed circuit board editor for Unix, Linux, Windows, and Mac systems. This Software runs across multiple platforms such as Unix, Linux, Windows as well as Mac systems. This Tool is widely used for electronics as well as electrical circuit designing that comes with schematic capture. PCB offers high end features such as an autorouter and trace optimizer which can tremendously reduce layout time.
  [ Hits: 104 | Votes: 0 | Rating: 0 ]

• JMSK - JMSK is a software modem that implements a good coherent MSK demodulator that has performance comparable to BPSK. Signals are demodulated from the soundcard. Modulated signals can be routed through the soundcard or to an external device such as a DDS module for direct RF modulation. The advantage of MSK compared to PSK is that non linear amplifiers can be used and has a faster roll off. It is an open source cross-platform program written in C++ Qt.
  [ Hits: 372 | Votes: 2 | Rating: 5.5 ]

• 5th order High Pass VHF Filter - Sometimes many VHF-UHF modern transceivers have problems with BROADCAST Interference and CROSS-modulation from FM commercial broadcast stations this article shows a simple Batteworth HI-Pass VHF Filter to reduce this problem
  [ Hits: 1209 | Votes: 8 | Rating: 6.12 ]

• Prevention and Suppression of RF Interference to Audio Systems - In this study, the author builds upon Muncy's research, demonstrating that radio-frequency current on cable shields affects audio systems through the "pin 1 problem" and shield-current-induced noise (SCIN). An enhanced equivalent circuit for ferrite chokes is proposed, addressing dimensional resonance and inductor self-resonance. Field tests confirm that chokes reduce interference across 500 kHz to 1,000 MHz. Guidelines for diagnosing and mitigating EMI from various sources are provided for product development and field installations.
  [ Hits: 47 | Votes: 0 | Rating: 0 ]