Radio Preppers

General Category => Antennas => Topic started by: gil on March 05, 2018, 01:02:32 pm

Title: Extend Handheld Radio Range With a Yagi-Uda Antenna.
Post by: gil on March 05, 2018, 01:02:32 pm


Gil.
Title: Re: Extend Handheld Radio Range With a Yagi-Uda Antenna.
Post by: CroPrepper on March 06, 2018, 06:25:50 am
Interesting results. I wondered how that works if only one pair of sticks is connected, but the principle how a Yagi works is quite ingenious (after googling it of course).
I saw people make such antenas for SOTA activities and portable use out from piano or guitar strings. I also saw a portable Yagi on WIMO.com for SOTA but its over 100€. I got a fiberglas heavy duty pole with 6m height, such a yagi would come in handy to pickup distant stations on simplex.
I may research a bit on how to use guitar wires for that as I am a guitar player and those wires are really form stable.

Thanks for sharing this diy project

Title: Re: Extend Handheld Radio Range With a Yagi-Uda Antenna.
Post by: Marcel on November 03, 2019, 10:18:36 pm
Hello Gil,

I want to build a 3 element tape mesure antenna
for 146.700MHz. Are the following
calculation correct ?

λ = c/f
λ = 300/146.7
λ = 2.044989775051125‬ meters

Reflector lenght .................. = 0.495 * λ
                                          = 0.495 * 2.044989775051125
                                          = 1.012269938650307‬ meters


Driven elements  .................. = 0.473 * λ
                                           = 0.473 * 2.044989775051125
                                           = 0.967280163599182‬ meters

Director lenght  .................. = 0.440 * λ
                                          = 0.440 * 2.044989775051125
                                          = 0.899795501022495‬ meters

Reflector to driven element spacing = 0.125 * λ
                                                          = 0.125 * 2.044989775051125
                                                          = 0.255623721881390‬ meters

Driven element to director spacing  = 0.125 * λ
                                                          = 0.125 * 2.044989775051125
                                                          = 0.255623721881390‬ meters

Does this make sense

Merci
Title: Re: Extend Handheld Radio Range With a Yagi-Uda Antenna.
Post by: gil on November 06, 2019, 05:27:14 am
Quote from: Marcel on November 03, 2019, 10:18:36 pmAre the following
calculation correct ?

Hi, I don't know. I use an online Yagi calculator like this one: https://www.changpuak.ch/electronics/yagi_uda_antenna_DL6WU.php (https://www.changpuak.ch/electronics/yagi_uda_antenna_DL6WU.php)