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How to build a multi-band dipole antenna with a single coax feed. Instructions for a 160M antenna that will fit in the space that a 75M dipole will with almost as good of results as a full size 160M dipole.

Build a 5 watt, 80 meter QRP CW Transceiver Designed by N1HFX

A helix will work in the normal mode when the diameter and pitch of the helix is less than 0.1 Lambda

This page describes two modifications W8WWV made to his AL-1200 amplifier. The mods were obtained from Ameritron, so they are official.

Army Field Manual 24-18 Appendix M with Graphics

A quick and easy method of programming memory channels The Icom IC-V8000 manual leaves much to be desired due to the translation. The operator's manual included with the Icom IC-V8000 can be very confusing to the new ham and the old timer alike, and lots of hams get very disgusted when trying to program the IC V8000 using the instructions provided with the operator's manual.

Buy, sell, trade vacuum tubes

Using the FT-857 Microphone Jack for Serial Control (CAT)

"A collection of nearly all facts around the YAESU Musen products; products, company history and much more"

Improvements to Using the Heath SB-200 Linear on Six Meters by Ron Klimas, WZ1V

SSTV Fundamentals, frequencies in use for SSTV and many SSTV related infos, includes Fax basics

Thermocouple ammeters are very rare these days, but the job they were perfect for - measuring antenna currents - is still a modern requirement especially in respect to groundplane currents. By David A. Reid PA3HBB G0BZF

The DXrobot, operational since 1999, offers a free, non-commercial service primarily for the VHF ham radio community. It specializes in automatic real-time E-skip warnings for **144 MHz** in both Europe and North America, delivered via email or SMS. Additionally, the system provides automatic aurora alerts for _50, 70, and 144 MHz_ openings through the same notification methods. Beyond real-time alerts, the DXrobot facilitates the reception of the latest DX-cluster spots via email, a feature useful for operators without immediate WWW or cluster access. The service also displays recent E-skip and aurora spots detected by the DXrobot on 50, 70, and 144 MHz, with updates every five minutes. Historical data includes lists of all DX spots from the previous day on 50, 70, and 144 MHz, updated daily. Key propagation data, such as MUF timeline, Solar X-rays, Geomagnetic Field, and Estimated Kp index, are also presented.

Here is how to adjust this popular tuner circuit so it transfers maximum power to your antenna without going snap

mods for the Yaesu FT-100 by radiomods.co.nz

FindU.com operates as a robust database archiving **APRS** (Automatic Packet Reporting System) data, including weather, position, telemetry, and message reports. It integrates data from both amateur radio APRS systems and the internet-based Citizen Weather Observer Program. This substantial 58 GB database is hosted on dual servers utilizing data replication, processing approximately 20 new reports per second to provide constantly updated information. The system supports various applications, such as displaying weather reports, tracking position data, and facilitating long-term vehicle tracking. A notable function involves forwarding over 100,000 near-realtime weather observations daily to the National Oceanographic and Atmospheric Administration (NOAA) for accuracy checks and use by NOAA and the National Weather Service. Additionally, it archives APRS reports from the International Space Station. Access to the database is primarily via dynamic web pages, with a comprehensive list of available CGIs detailed on a dedicated server page. While direct URL parameter editing is possible for advanced users, alternative web pages with forms simplify query submission. The platform utilizes **PNG** images for dynamic graphics, a choice made due to past GIF patent issues, ensuring broad browser compatibility.

An easy to build spectrum analyzer

K6SGH introduce the hamloop antenna L7 series

Here you can find Boatanchors on the air.

KWRTTY V1.1.3, released on February 4, 2008, is a freeware RTTY reception program designed for Windows operating systems (Win95 and higher, requiring a minimum 133 MHz Pentium processor and 32 MB RAM). Its primary function is to decode and log amateur radio **RTTY** transmissions, including the capability to set up a private RTTY mailbox that records only messages addressed to the user's callsign. The software is specifically optimized for receiving and logging marine weather reports from the DWD (Deutscher Wetterdienst), categorized by sea areas, making it particularly useful for sport boat operators. The duration of logging is limited only by available RAM. For its core functionality, KWRTTY requires the **MMTTY-Engine** by Makoto Mori, JE3HHT, as an interface between the sound card and the program. This engine, also freeware, needs to be copied into the same directory as KWRTTY. The program's design focuses on continuous logging of specific RTTY content, offering a specialized tool for both general amateur radio RTTY monitoring and dedicated weather report reception, distinguishing it from more general-purpose digital mode software.

Hexagonal wire beams for all hf bands, technical resource, EZNEC files, tools for antenna modeling and documentation. You can also order parts to build your own antenna.

By ON4CFC Pascal, describe how to build a Sperrtopf or Sleeve antenna for the 144 Mhz, PDF File by antennex

3 Band vertical Marconi-antenna for the bands 40, 80, 160 meters with a ground net of wires as radials.

The Kenwood TH-F6A handheld transceiver can achieve an extended transmit frequency range of 137-174 MHz, 216-235 MHz, and 410-470 MHz by removing a specific diode and chip resistor from the main PCB. This modification also expands the receive range on the A-band to 142-152 MHz, 216-235 MHz, and 420-450 MHz. For the TH-F7E, the transmit range extends to 137-174 MHz and 410-470 MHz, with a corresponding receive range on the A-band. Performing these hardware changes will reset and initialize the radio's memory contents, necessitating prior backup of important channel frequencies. Instructions are provided for constructing a homemade PC programming cable compatible with the Kenwood TH-G71A, TH-F6A, and TH-F7E. The interface utilizes an RS-232-to-logic (0-3.3V) level-shifter and a full-duplex serial connection, adapting the Kenwood PG-4S cable schematic for the TH-G71's 2.5mm and 3.5mm phono plugs. Specific schematic tweaks include changing R1 from 150 ohms to 1K ohm to optimize power from the serial port and adding a 150K ohm resistor between the Radio TXD and ground to manage the 3.3V I/O pin. Detailed plug pinouts for the 2.5mm and 3.5mm connectors are presented, with the interface's TXD connecting to the ring of the 2.5mm plug and RxD to the shield of the 3.5mm plug. Ground connects to the shield of the 2.5mm plug, while the tips of both plugs are no-connects. Debugging procedures cover verifying positive and negative power rails from the serial port, checking component polarities, and testing level-shifting and inversion functions of the interface. Software setup involves enabling "TC ON" (Menu 15 for TH-G71, Menu 9 for TH-F6) and using Kenwood's MCP programming software.

Manufacturers of high performance low power am transmitter products: sstran amt3000, bc-100, and the mw-250. for home and professional use.

Another good collection of TS-850 modifications

A marriage of the windom and slinky antennas, experimental home brew antenna by NC4TC

Report of solar & geophysical activity

A simple, cheap, efficient tv antenna that you can make yourself.

An interesting page about Quad antennas. Modelling QUAD antennas, comparing quad antennas to yagi antennas. Information on QUAD Antenna tuning and home brewing with help on calculating dimensions and tuning.

KB6NU article on W3EDP antennas

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.

Need a variable power supply that is short circuit protected and over voltage protected; Here is a good one that can be built cheap by VE3IVJ

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

Home page of the Dallas Amateur Radio Club, located in Dallas, Texas. The DARC is one of the oldest clubs in the country, founded in 1914.

Preamp & Power Amp By Alkberto, I0XGR

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

by Dr. D.T. Emerson, National Radio Astronomy Observatory (NRAO++). Antenna Compendium Volume 4, pp 64-68, 1995, published by the ARRL.

The Grid Yagi (or Grid Quad) is a high performance yagi antenna that can be built with readily obtainable inexpensive materials. Described here is a 6 element 2 meter version with a boom length of about 1 wavelength, shown

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.

Collection of TS-50 mods, LCD display dark, TS50<-->AT50 communication, TS-50 Power Mod for QRP, TX Coverage mod TS-50, CAT control for TS-50S

A compact directional receiving antenna

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

Images and Radio Shack composition

How to improve the gain of your 5 element Tonna yagi for 50 MHz by roughly 3 db!

A dual driven antenna for the 6 meters band.

A monoband end-fed half wave for 10m, 20m or any other HF band, includes a PDF with detailed information to build your own monoband or multiband antenna

This is from a posting on the BARK PBBS Keith, WB2VUO

Here is an antenna for the nineties. It's strong, computer designed, and has lots of gain. It is a full size, four element beam on 10, and three elements on 15 meters

The half wave dipole antenna is a simple and practical antenna model that consists of a half wavelength long centre fed conductor.