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85 links

Small Transmitting Loop Project - Article about small magnetic loop antennas with notes on realization of magnetic loops for several HF bands and the six meter band
[ Hits: 1080 | Votes: 3 | Rating: 10 ]

VHF Baluns: Fact and Fancy - Our ideas about HF baluns have changed dramatically in recent years. The focus today is very much on suppressing unwanted common-mode RF currents, to reduce both the received noise levels and the risks of causing interference on transmit.
[ Hits: 283 | Votes: 0 | Rating: 0 ]

A Small Loop for 20 and 15 meter band - A Small Transmitting Loop Antenna for 14MHz and 21MHz, an antenna you might consider if you have limited space, Based on material originally published in Amateur Radio, November 1991
[ Hits: 421 | Votes: 0 | Rating: 0 ]

Designing VHF/UHF Quad Antenna - The information in this article has come from many amateur sources, the most notable was from WA6TEY (sk 1985) Ray Frost, who was a pioneer of VHF Quad designs and one of the best Southern California Transmitter Hunters. Ray built hundreds two meter quads in single and paired configurations as well as his famous mobile radio direction finding quad.
[ Hits: 979 | Votes: 7 | Rating: 8 ]

SWR ANTENNA ANALYZER + WSPR TX - Available worldwide can be used as Arduino Shield or plug it in to you PC , or with a bluetooth adapter connect to Android. With a highly optimized software, KAI200 brings you: a. Antenna analyzer form 1 up to 200 Mhz; b. WSPR transmiter (set up by serial terminal); c. Square Wave Signal generator KAI200 is all you need for your radio whatever it is Yaesu, Icom, Kenwood or Drake and DIY projects.
[ Hits: 327 | Votes: 8 | Rating: 9.62 ]

PolEx Technologies - Makers of the The Polar Explorer transmitter, which operates on 9 HF bands from 160 through 10 meters and is capable of 500 watt peak output power on SSB, CW, AM, FM and RTTY. It is intended to be used in conjunction with a transceiver.
[ Hits: 501 | Votes: 0 | Rating: 0 ]

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
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Portable Amateur Radio Operations - The main issues with portable HF operations have become not issues of the transmitting and receiving equipment itself but of providing power and antennas
[ Hits: 497 | Votes: 2 | Rating: 5.5 ]

Northern California Transmitter Hunters - The Northern Calfornia Transmitter Hunters are a group of people that share a common interest in amateur radio transmitter hunting.
[ Hits: 191 | Votes: 0 | Rating: 0 ]

Ham Radio: Using Repeaters - The most basic form of repeater receives communication on one frequency and re-transmits at a different frequency. This is known as duplex communication. Repeaters are generally set up to operate with FM modulation on the amateur bands within the VHF (30 MHZ – 300 MHZ) and UHF frequencies (300 MHZ – 3 GHz). These are generally the frequencies used by handheld and mobile devices.
[ Hits: 92 | Votes: 1 | Rating: 8 ]

Decoding Russian Meteor-M2 satellite images in real time - The Meteor-M N2 is a polar orbiting Russian weather satellite that was launched on July 8, 2014. Its main missions are weather forecasting, climate change monitoring, sea water monitoring/forecasting and space weather analysis/prediction. Meteor-M N2 transmits images using the digital LRPT protocol at around 137.1 MHz with can be received with an RTL-SDR.
[ Hits: 200 | Votes: 0 | Rating: 0 ]

What is System Fusion - System Fusion is Yaesu’s implementation of Digital Amateur Radio, utilizing C4FM 4-level FSK Technology to transmit digital voice and data over the Amateur radio bands
[ Hits: 112 | Votes: 0 | Rating: 0 ]

Arduino Beacon - A new multi-mode QRP radio beacon built around the Arduino. The beacon started with the usual lash-up on the bench, hooking the previously reported Wotduino and DDS Shield up to a driver and a transmitter module, as previously used for the Raspberry Pi beacon
[ Hits: 706 | Votes: 0 | Rating: 0 ]
The WB0RIO 28 Mhz Arduino Beacon - This project involves the construction of a 5 Watt Morse code beacon transmitter that operates in the 28.200 to 28.300 section of the 10 Meter Amateur Radio band. The beacon controller uses an Arduino Uno microprocessor board to produce the three signals that control the transmitter.
[ Hits: 625 | Votes: 0 | Rating: 0 ]

Attenuator for Fox Hunting - An Active attenuator for transmitter hunting QST Article november 1992
[ Hits: 576 | Votes: 1 | Rating: 9 ]

Morse Code Beacon Keyer - This circuit stores a morse code message as bits in an EPROM chip, the message controls a relay that keys a CW morse code transmitter. An Arduino processor can also be used in place of this circuit, that eliminates the need to build the circuit and program an EPROM.
[ Hits: 381 | Votes: 0 | Rating: 0 ]

A Three-Band One-Tube Novice Transmitter - A homebrew radio transmitter project, based and inspired by the original 30 Watts input on 80 50 and 15 meters band transmitter by W11CP
[ Hits: 345 | Votes: 2 | Rating: 10 ]

Preventing CW key clicks - Key clicks are generally undesired clicks or thumps generated by a CW transmitter as the key is put down or let up. How much does the rise time or bandwidth of a CW signal need to be limited to prevent other QSOs on adjacent frequencies from being annoyed by key clicks?
[ Hits: 93 | Votes: 0 | Rating: 0 ]

Gimme Five - QRP SSB Transceiver - Gimme Five reloaded, a compact 5 band QRP SSB transceiver in SMD technology. This unit covers 5 bands within the amateur radio spectrum (3.5, 7, 14, 21 and 28 MHz). Receiver is a single conversion unit with an interfrequency of 9 MHz. Transmitter uses 5 stages and has got a power level of 10 watts PEP output.
[ Hits: 285 | Votes: 1 | Rating: 10 ]

Cross Band Repeaters - Crossband Repeating is a process where a Ham transmits one signal on one band (typically UHF), and it is received by another radio with a better antenna/power installation, and re-transmitted (typically on VHF) to another radio system, or a repeater. Everyday examples of cross-band repeaters are repeater receive sites that hear the input signals on 2m and retransmit those signals on a frequency higher than 220 MHz.
[ Hits: 207 | Votes: 0 | Rating: 0 ]