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RF engineering solutions, HF VHF antenna systems and radio communications equipment.

About numbers stations, and their criptic transmissions, where to listen to them and some audio recording samples by fascinating shortwaves

The Upside-Down Umbrella Antenna by Don Keith N4KC

The ZS6BKW wire antenna, a variant of the G5RV, utilizes a specific 13m (42.6 ft) length of 450-ohm window line as its matching section, feeding a 28.5m (93.5 ft) flat-top element. This design aims for lower SWR on 40m, 20m, 17m, 12m, and 10m compared to a standard G5RV, often achieving SWR values below 1.5:1 on these bands without an antenna tuner. The feedpoint impedance transformation provided by the window line allows for direct connection to 50-ohm coax on multiple bands. F4FHH's experience involved constructing the ZS6BKW and evaluating its performance against an _OCF dipole_ (Off-Center Fed) on various HF frequencies. The article includes observations on SWR readings and operational effectiveness, highlighting the ZS6BKW's suitability for multi-band operation. The antenna's overall length, including the flat-top and window line, is approximately **41.5 meters** (136 feet), making it a significant wire antenna for fixed station use. Comparative analysis with the OCF dipole provided practical insights into the ZS6BKW's advantages and limitations, particularly concerning bandwidth and tuner requirements.

a comprehensive listing of both Military and Civil HF networks from Australia and it's surrounding neighbours as well as from countries around the world.

New User Tips for VHF-UHF Operation by Dave Schultheis WB6KHP

Some antenna manufacturers place baluns at the incorrect location in LPDA arrays, or tell you to route the cable incorrectly. This can cause substantial RFI and all sorts of weird problems like RF into house wiring.

Schematic Manual of the 3 element Yagi antenna by ECO antenne

A free application that searches more than 100 web-accessible sources to locate QSL information for a callsign that you enter once

Icom IC-9100 on youtube

A Windows freeware DX cluster client, allows you to monitor DX spots from users worldwide includes DX filtering and statical functions.

Professional Two Way Radio communication by ICOM.

K6ZB Bruce presentation of technologies to allow ham radio operate via internet

VHF quad antenna for transmitter hunting.

Working with SDR#, adjusting frequency correction and basic setup.

KB1GW's collection of beverage antenna information

An home made trapped dipole antenna for 40 and 60 meters band by 2E0HTS

Restoring vintage amateur radio gear often presents challenges with accurate dial calibration due to the non-linear characteristics of analog tuning capacitors. This resource details the construction of a 100 kHz crystal calibrator, a crucial tool for precisely setting the frequency of older rigs lacking digital readouts. The design cleverly circumvents the scarcity and cost of 100 kHz crystals by utilizing a readily available 8 MHz microprocessor crystal, such as a _HC49U_ type, in conjunction with common _CMOS ICs_ like the 74HCT00 quad NAND gate and 74HCT393 dual 4-bit binary ripple counter. The circuit employs a two-stage frequency division process: the 8 MHz crystal oscillator output is first divided by 16 to yield 500 kHz, then further divided by 5 to achieve the desired 100 kHz output. A 5.1-volt Zener diode, _1N4733A_, regulates the power supply for the HCT series logic. The article also provides a modification to produce a 50 kHz calibrator by altering the counter reset logic. Installation involves feeding the output to the receiver front end, ensuring it's post-TR relay to prevent RF damage, and incorporating an ON/OFF switch for the 12V supply line.

Build the Moorabbin, a regenerative receiver for the AM broadcast band by Peter Parker VK3YE

Wholesale distributor of CB radios, parts, antennas, microphones, power supplies, crystals, echo boards, expanders, meters and CB accessories.

Antenna switch at K6XX

Learn a little bit about how duplexers work and building your own.

A project to build a cross band repeater using a pair of Baofeng UV5R handheld transceivers.

A basic article on end-fed antennas by KB6NU

It's a whole new way of preparing for the government FCC License examination. The classroom is your home.

Tower and antenna rotation equipment, insulators, rotor control cables, ancillary products

A small magnetic loop ready for a hand held walk and talk operation by PY1AHD

Compiling an extensive collection of technical information, the Repeater Builder's website serves as a critical resource for those involved in amateur and commercial repeater systems. It covers a broad spectrum of topics essential for the design, construction, and ongoing maintenance of these vital communication hubs, drawing from years of practical experience in the field. The site provides detailed insights into various aspects of repeater technology, including specific information on VHF and UHF bands, such as 2-meter systems. Users can find data related to repeater logic, control systems, and interfacing with other radio infrastructure, all presented with a focus on practical application. Authored by Kevin Custer, W3KKC, the content reflects a deep understanding of repeater operations and engineering, offering guidance that extends beyond basic setup to advanced troubleshooting and optimization.

This article describes how to use a phone line as a shortwave receiving antenna, but be carefull telephone lines present a potential shock hazard, use at your own risk

Satellite Tracking and Orbit Propagation, Reports and Mission Planning Products, Pass Scheduling and Orbit Event Analysis, Dynamic Communications Link Modeling, 3-D Visualization of Complex Scenarios User Defined Regions and Contours, Constellation and Formation Flying Support, Global Positioning System Coverage

Multiband no trap no gap antenna. This Antenna is a small wonder, easy to build and allow you to work all HF spectrum with your TRX and it's internal ATU.

Police and Security Broadcasts at Harvard University, Boston-Area University Police Radio. Cambridge; Boston.

The no counterpoise antenna

SDR# (read SDR Sharp) is a high performance Software Defined Radio application. SDR sharp is a fully featured SDR capable of handling samplerates from kHz level soundcards up to multi hundred MHz dedicated samplers, thanks to its multi-core architecture.

EME operation news, typical moonbounce audio recordings

Premier OEM of portable tower systems, Communication-Site-on-Wheels (COWs), heavy-duty fixed foundation telescopic structures commercial and military, worldwide sales and leasing

Homebrew a 1/4 wave 80 meter vertical using aluminium tubing

This note describes a relatively small, but efficient, loop antenna initially created for portable operation. With suitable modifications, it can be adapted for fixed station use. In this age of CC&Rs, an antenna similar to this may very well be the answer to your problems. Have a look, be inspired, get out the torch / soldering iron and create your own version!

How to build a beacon keyer for 28 MHz using an old CB Radio transceiver, by Tom Sevart

Add Solar-Terrestrial data to your website, by adding a simple html code to your pages by Paul L Herrman

A 10 Bands mobile antenna for about the price of 2 mobile monobanders.

Unsing FT-950 in contests by K9ZW

The design of Ruthroff broadband voltage transformers

by Don Graham, VK6HK

Details and very early history of yaesu musen amateur radio equipment in australia . 1966 yaesu first trasceiver.

Simple, inexpensive and lots of fun! Here is an easy to make home brew antenna that can get you on the air working satellites or be built for use as a portable hand held antenna to extend the range of your HT.

A quick vertical for 160 meters portable use

2 element reversible verticals, small footprint, big results.

A compact directional receiving antenna

Moxons work great, and they take up less space than full size two element Yagis