One of the most practical antennas for feild work is the half-wave end-fed
antenna. It employs a 49:1 transformer to lower the impedance of a half-wave
wire fed at the end. It allows multi-band operation with certain wire lengths,
mainly 20 meters and 40 meters. The longer wire covers bands from 80m to 15 and
One core will handle 100W SSB. If you want to run high duty-cycle modes, add additional cores to your transformer. https://elginradio.wordpress.com/2017/10/17/end-fed-half-wave-antennas/
A Yagi–Uda antenna, commonly known as a Yagi antenna, is a directional antenna
consisting of multiple parallel elements in a line, usually half-wave dipoles
made of metal rods. Yagi–Uda antennas consist of a single driven element
connected to the transmitter or receiver with a transmission line, and
additional "parasitic elements" which are not connected to the transmitter
or receiver: a so-called reflector and one or more directors. It was
invented in 1926 by Shintaro Uda of Tohoku Imperial University, Japan, and
(with a lesser role played by his colleague) Hidetsugu Yagi.
Hidetsugu Yagi holding his famous Yagi-Uda design of radio antenna, which he co-developed with Shintaro Uda in the 1920s at Tohoku Imperial University in Japan.
This is buried in the Acknowledgements section and can easily be missed.
Yagi Calculator is a program to assist with the design of long yagi antennas. It uses the graphs and principles developed by DL6WU and printed originally in the German Radio Magazine VHF Communications (March 1982). The article was titled Extremely Long Yagi Antennas. For best front to back ratio it is recommended that a yagi be constructed with one of the following numbers of elements - 10,14,19,24. Yagi builders are reminded that DL6WU designs are primarily for long yagis. A boom length of 2 wavelengths (or 10 elements) would be a minimum sized antenna. On the other hand, yagis with as few as 8 elements have used the design and worked very well.
Download the windows program, SetupYagiCalculator.exe from John Drew's site. It runs under wine without any issues on my Ubuntu Version 18.04.
An excellent resource for building Yagi Antennas is The Welshman, G0KSC. His website can be found here: Free Yagi Antenna Designs for Ham Radio:
Folded Dipoles for VHF/UHF Yagis:
This is about 5.5 meters in length. 18ft Its Frequency Range is 26-29mhz and it
can be Tuned to most Amateur Bands with a good Tuner. The MK1 is Currently Pre
Tuned for 27mhz, Via an Antenna ANALYZER.
Its Power Rating is 1 KiloWatt, it can also be Adjusted in length. The MK1 is
the Best Performing 1/2 wave vertical ever made, with its Heavy Duty 1KW Pre
Tuned External Coil. The Coil has been mounted in Original Design, that can be
Easily removed and Serviced or replacement with other Amateur Loading Coils.
Example: 80m/40m/20m/ Etc.
The MK1 can also be shortened for 10m and 6m. Truly a Diversified and Modifiable
Base Station Vertical, that can also be tuned to the Marine Band 28.880mhz AM.
The antenna is adjustable from the top of the antenna for fine tuning as well as the coil which is made of 2 mm copper. End fed SO-239 Connection.
PIM is a form of intermodulation distortion that occurs in components normally
thought of as linear, such as cables, connectors and antennas.
PIM shows up as a set of unwanted signals created by the mixing of two or more
strong RF signals in a nonlinear device, such as a loose or corroded connector,
or nearby rust. Other names for PIM include the diode effect and the
rusty bolt effect.