Yagi antenna production

The Yagi antenna is a directional antenna. It consists of an active vibrator and multiple passive vibrators placed on the same plane and perpendicular to the metal rod connecting their centers. Generally, one passive oscillator is a reflector, and the remaining passive oscillators are directors. Because the metal rod passes through the voltage wave node on the vibrator and is perpendicular to the antenna, the metal rod has little effect on the near field of the antenna. The active vibrator must be insulated from the metal rod.
As can be seen from the data in the table below, the gain of the Yagi antenna is higher than that of the vertical antenna and dipole antenna. (From "Antenna Radio Wave Propagation", edited by Xu Kunsheng and Jiang Zhongyong of Northern Jiaotong University)

Antenna form Number of reflectors Number of directors Number of active elements Directivity coefficient

Dipole 0 0 1 0 dB
Two units Yagi 1 0 1 3 ~ 4.5dB
Two units Yagi 0 0 1 3 ～ 4.5dB
Three units Yagi 1 1 16 ~ 8dB
Four units Yagi 1 2 1 7 ～ 10dB
Five units Yagi 1 3 1 9 ～ 11dB

As can be seen from the table above, the more Yagi antenna units, the stronger the directivity. But the increase of the unit is not proportional to the directivity. When there are too many units, the operating frequency band will be narrowed, and the size of the entire antenna will be too large.

In the short wave band, the wavelength is longer, and it is more difficult to make a Yagi antenna. In the ultra-short wave band (V / U), because the wavelength is short, it is easier to make a low-cost Yagi antenna.

The mathematical calculation of Yagi antenna is complicated (I feel dizzy when I encounter mathematical derivation), but many engineering or theory books give its size, as long as you follow these data, you can make a good pair of YAGI!
The dimensions of the five-unit Yagi antenna are shown in Figure 1.



If you make a four-unit Yagi antenna, as long as the director D is not installed, the antenna will also look smaller. If you want to make seven units, add two director units on the basis of the above picture, the length is 84% ​​and 82% of the half wavelength respectively. The interval of the newly added units is still 0.2 times the wavelength.

The Yagi antenna I made in the 70CM band was originally a four-element unit. Each vibrator and its connected metal rod were made of copper electrodes (2.5 mm diameter) provided by BG4RUV. About a month later, I bought a 2-meter-long copper bar with a diameter of 4 mm, and made a detachable four-unit Yagi antenna (a rectangular copper tube was found as a pole connecting each vibrator, and each vibrator was screwed and The pole is fixed, easy to carry). The resonance point of the first antenna is about 2 MHz lower than the predicted center frequency (435 MHz), but the SWR within 430 to 440 MHz is not high, the lowest SWR is less than 1.1, and the highest SWR is not greater than 1. 4. The SWR of the second antenna has little fluctuation in the entire 70CM frequency band, with a maximum of about 1.2. Later, I made some changes to this detachable antenna and used the remaining materials to make three primers, so that my antenna can be assembled into a four-unit Yagi antenna or a seven-unit Yagi antenna.

If you want to make a Yagi antenna, but do not require strong directivity, you can try to make a three-unit Yagi antenna. The dimensions are given here (Figure 2).

In-depth analysis of the first-level cache and second-level cache of the technical zone CPU eMMC mass burning dilemma, do you really know? Isolation flyback and non-isolated BUCK application design plan Schottky barrier diode selection and application guide How to use Altium in program design Designer puzzle?

Follow WeChat

Interesting and informative information and technical dry goods

Download Audiophile APP

Create your own personal electronic circle

Follow the audiophile class

Lock the latest course activities and technical live broadcast
Collect People collection
share it:
comment
Publish

related suggestion

Shortwave antenna manufacturing method

Commonly used short wave antennas are mainly divided into 3 categories, the first category is vertical antenna (GP), the second category is even-level antenna (DP), and the third category is Yagi antenna (Y ...

Posted at 2014-03-25 16:12 • 664 times read
Shortwave antenna manufacturing method
The engineer made a story: Niu Ren made the whole process of WIFI Shuangling antenna

The story made by the engineer: The whole process of Niuren's homemade WIFI Shuangling antenna. This production refers to the drawings collected on the Internet. It is said that there is a gain of about 11DB ...

Posted at 2012-08-17 18:25 • 120705 views
The engineer made a story: Niu Ren made the whole process of WIFI Shuangling antenna
wifi antenna production and testing

This production refers to the drawings collected online. It is said that there is a gain of about 11DB, and the test is indeed true after completion.

Posted at 2012-04-12 13:53 • 53607 views
wifi antenna production and testing
About "balance-unbalance conversion and impedance matching" in antenna production

The distance between the feeding ends of the active elements of the antenna is about 5-10 mm. I did not add "ping ...

Posted at 2006-04-16 20:08 • 1854 views
About "balance-unbalance conversion and impedance matching" in antenna production
144MHZ nine section Yagi antenna

Posted at 2006-04-16 20:08 • 1309 views
144MHZ nine sections Yagi antenna
Talking about Yagi Antenna

[Wei Bing] As the popularity of the V / U band increases, homemade Yagi antennas have become a hot topic again. ...

Posted at 2006-04-16 19:55 • 849 views
Talking about Yagi Antenna
[Photo] FM three-unit Yagi antenna production

Published on 2006-04-15 21:10 • 3153 times read
[Photo] FM three-unit Yagi antenna production
var check_allow = "/d/Api/iscantalk.html"; var add_url = '/ d / article / write /'; function CheckLogin () {now_uid = ''; var ElecfansApi_checklogin = '/ webapi / passport / checklogin'; var logout_url = "{: U ('Login / logout')}"; var logout_url = 'http://bbs.elecfans.com/member.php?mod=logging&action=logout&refer=front'; $ .get (ElecfansApi_checklogin, function (data, textStatus) {if (data! = "") {EchoLoginInfo (data); CheckEmailInfo (data); data = $ .parseJSON (data); now_uid = data.uid; / * var login_content = 'write an article
'+ data.username +'
Quit '; * / var login_content =' write an article
'+ data.username +'
Set exit '; $ (' # login_area '). Html (login_content); var win_width = $ (window) .width (); if (win_width> 1000) {$ ("# mine"). MouseDelay (200) .hover (function () {$ ("# mymenu"). show ();}, function () {$ ("# mymenu"). hide ();});}} else {var content = 'Login Registration'; $ ('# login_area'). html (content); $ (". special-login"). click (function (e) {$ .tActivityLogin (); return false;});}});} $ (function () {// comment ------------------------------- var comment = $ ("# comment"); var comment_input = $ ("# comContent"); // Submit comment click event interaction $ ("# comSubmit2"). on ('click', function () {var content = comment_input.text (); // Empty input box comment_input. html (""). focus (); // Submit data to server $ .ajax ({url: '/plus/arcComment.php', data: {aid: $ ("# webID"). val (), dopost : 'apiPubComment', content: content}, type: 'post', dataType: 'json', success: function (data) {// Data format returned: if (data.status == "successed") {// Build temporary comment DOM var dom = ''; dom + = '
'; dom + =' '; dom + ='
'; dom + ='

'+ data.data.username +' '; dom + ='

'; dom + =' '+ content +' '; dom + =' '; dom + =' just now '; dom + =' '; dom + =' '; // insert a temporary comment to the list $ ("# comment ") .append (dom);} if (data.status ==" failed ") {// alert (data.msg); layer.msg (data.msg);}}}); return false;}); (function () {/ * * Insert single sign-on JS * / var setHost = 'https://passport.elecfans.com'; // Set domain name var script = document.createElement ('script'); script.type = 'text / javascript'; script.src = setHost + '/public/pc/js/t.passport.js'; script.setAttribute ("id", "sso_script"); script.setAttribute ("data-ssoSite", setHost); script.setAttribute ("data-ssoReferer", encodeURIComponent (location.href)); script.setAttribute ("data-ssoSiteid", "11"); var body = document.getElementsByTagName ("body"). item ( 0); body.appendChild (script);}) () / * * It is recommended to modify the style of the article without a picture * * / $ (". Article .thumb"). Each (function () {if ($ (this). find ('img'). attr ('src') == "") {$ (this) .find ('img'). remove (); $ (this) .parent (). css ('padding-left ',' 0px ');}}); / * Baidu share * / window._bd_share_config = {common: {bdText: '', // Custom share content bdDesc: '', // Custom share summary bdUrl: window.location.href, // Custom share URL address bdPic: ''} , share: [{"bdSize": 60, "bdCustomStyle": true}]} with (document) 0 [(getElementsByTagName ('head') [0] || body) .appendChild (createElement ('script')). src = 'http://bdimg.share.baidu.com/static/api/js/share.js?cdnversion=' + ~ (-new Date () / 36e5)]; var add_url = '/ d / article / write / '; // var check_allow = "{: U (' Api / iscantalk ')}"; var check_allow = "/ d / api / iscantalk"; var click_items_length = $ ('. art_click_count '). length; if ( click_items_length> 0) {var id_str = ''; $ ('. art_click_count'). each (function () {id_str + = $ (this) .attr ('data-id') + ',';}) // var url = "{: U ('Api / getclickbyids')}"; var url = "/ d / api / getclickbyids"; var id_data = 'id_str =' + id_str; $ .ajax ({url: url, data: id_data, type: 'post', dataType: 'json', success: function (re) {if (re.list.length> = 1) {var list = re.list; for (var i in list) {var t emp_id = list [i] ['id']; var temp_span = $ (". art_click_count [data-id =" + temp_id + "]") temp_span.html (list [i] ['click']);}} }})} $ ("# comContent"). click (function () {if (now_uid == '') {$ .tActivityLogin (); return false;}}) $ (function () {var follow_wrap = $ ( ".author-collect"); var now_uid = "{$ _super ['uid']}"; var face_src = "{$ _super ['uface']}"; var getFollowNum = $ (". followNum strong"). html (); // Follow $ (window) .on ('click', '.author-collect', function () {if (now_uid == '') {$ .tActivityLogin (); return false;} if ( $ (this) .attr ('id') == 'follow') {$ .post ('/ d / user / follow', {tuid: article_user_id}, function (data) {// Data format returned: if (data.status == "successed") {$ (". followNum strong"). html (++ getFollowNum); follow_wrap.html ('followed'). attr ('id', 'cancelFollow'). css ( 'background', '# 999'); var follow_user = ' '; $ (' # follow_list '). append (follow_user);} if (data.status == "failed") {alert (data.msg);}});} else {// Unfollow if ($ ( this) .attr ('id') == 'cancelFollow') {$ .post ('/ d / user / cancelFollow', {tuid: article_user_id}, function (data) {// Data format returned: if (data .status == "successed") {follow_wrap.html ('Follow'). attr ('id', 'follow'). css ('background', '# f90'); $ (". followNum strong"). html (-getFollowNum); $ ('# follow_list .face'). each (function () {var target_uid = $ (this) .attr ('data-uid'); if (target_uid == now_uid) {$ ( this) .remove ();}})} if (data.status == "failed") {alert (data.msg);}}); return false;}}});});}); / * var myface = "{$ _super ['uid'] | avatar}"; var myname = "{$ _super ['username']}"; var article_id = {$ article ['id']}; var article_user_id = {$ article ['mid']}; // Article author ID $ (function () {<notempty name = "clearnum"> // Reduce the number of reminders var count = parseInt ($ ("# noticeCount"). html ()); count = count-{$ clearnum}; $ ("# noticeCount"). html (count); if ( count

LYF Copper Lube Terminals

Our company specializes in the production and sales of all kinds of terminals, copper terminals, nose wire ears, cold pressed terminals, copper joints, but also according to customer requirements for customization and production, our raw materials are produced and sold by ourselves, we have their own raw materials processing plant, high purity T2 copper, quality and quantity, come to me to order it!

LYF Copper Lube Terminals,Ring insulated terminals

Taixing Longyi Terminals Co.,Ltd. , https://www.longyicopperlugs.com

October 15, 2024