8.5 DB gain for less than $40.00 – 50MHz Yagi

by W3GAS

The Yagi is one of the simplest directional antennas you can build today. There are no moving parts, and the Yagi can be  matched to 50 OHM very easily using GAMMA or T-MATCH. My preference is the GAMMA MATCH. The antenna is totally in the ground circuit of the coax and only the GAMMA match is tuned to the frequency of choice. (We will discuss the GAMMA match later in the article). Please understand that there are some formulas you should keep in mind. These are available in the Antenna Handbook and many other reference books. I use Joesph Carr’s book “Practical Antenna Handbook” because it is written with simple in mind. That means, simple, not incorrect or misleading…just simple.
The length of the elements from above were taken from these formulas, but they are NOT on the money. They best fit the need for this low budget application. Here then is the formula that you can use, if you decide to tune the beam to fit your needs. All beams in HF are derived from this formula:
ELEMENT LENGTH  L = K/F (L is length, F Frequency in MHz. and K is the constant)
SPACING is based upon 0.15 – 0.31 wavelengths, although I generally use 0.2 – 0.25.
The K constant is 492 for the REFlector, 492 for the DRIven element and 462 for Director2 and 460 for Director1 (457 for Director3 if added).
Remember that there is a FREE TO USE software program that implements these same formulas and takes a lot of the guess work out of design. The link is located lower in this text.

The feedpoint will naturally be 72-75 ohms. After all most designs use a DIPOLE MATCH system and while most Ham’s are more familiar with a DIPOLE, this is not the best way to match a parasitic array. What tends to happen is based upon any DIPOLE in free-space. As soon as we add elements and adjust height off ground the Dipole match tends to change impedance and we come away with an antenna that may be difficult to tune, especially while up on the roof or tower. While on the ground it seems perfect, put it in the air and it just ain’t the same. Remember that additional elements will change the center of balance and that places the driven element further away from the main mast center point. Adjusting a DIPOLE element on the tower is damn near impossible….READ FULL ARTICLE

More

Antenna Chameleon F-LOOP VS Chameleon P-LOOP

October 19, 2016 No comments

“This is the long awaited Chameleon F-LOOP vs Chameleon P-LOOP review. In this video we go through the design and functionality of each antenna,... Read more

Digital Mode Operators Invited to Take Part in 2016 Most Wanted DXCC Entities Survey

April 29, 2016 No comments

Digital mode operators are invited to participate in the 2016 Digital Mode Most Wanted Survey. Previously known as the “RTTY Most Needed DXCC Entities... Read more

Amateur Radio Satellite Pioneer’s Estate Will Boost ARRL Endowment Fund

July 21, 2015 No comments

The ARRL will benefit from the largesse of the late Amateur Radio satellite pioneer Cliff Buttschardt, K7RR (ex-W6HDO), and his late wife Mable Vierth... Read more

Ham Radio Deluxe version 6.6.0.236

July 01, 2019 No comments

    https://www.hamradiodeluxe.com/   Read more

M-1 Yaesu Reference Microphone

September 12, 2016 No comments

The M-1 Reference Microphone is the ultimate, high-quality, innovative desktop microphone, dedicated to the most discriminating Ham Radio Operators. I... Read more

Radio ‘hams’: The legacy of Iraq’s amateur operators lives on

July 03, 2018 No comments

A community of clandestine radio enthusiasts remains active inside the country  by Sofia Barbarani Ahmed Al Amshawi was just 17-years-old when he firs... Read more

The Spectrum Monitor — October, 2016

September 28, 2016 No comments

LnR’s New LD-11: A Very Red, QRP, All-Mode, All-Band Transceiver By Thomas Witherspoon K4SWL LnR Precision, Inc., is a North Carolina-based company th... Read more

Reported Russian Ham Band Intruders Continue to be Troublesome

October 11, 2018 No comments

Ham Band Intruders Ham Band Intruders The International Amateur Radio Union Monitoring Service (IARUMS) reports interference on 40 meters from various... Read more