{"id":858,"date":"2014-05-17T20:47:36","date_gmt":"2014-05-17T23:47:36","guid":{"rendered":"http:\/\/www.viazap.com.br\/?p=858"},"modified":"2014-05-17T20:47:36","modified_gmt":"2014-05-17T23:47:36","slug":"wifi-sinal-canais-interferencia","status":"publish","type":"post","link":"https:\/\/blog.clusterweb.com.br\/?p=858","title":{"rendered":"Wifi sinal canais interfer\u00eancia"},"content":{"rendered":"

objetivo<\/h1>\n
\n

Esclarecer d\u00favidas acerca de frequ\u00eancia, sinal e canais wifi em redes 802.11b e 802.11g.<\/p>\n<\/div>\n

tabela informativa<\/h1>\n
\n
\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
canal<\/th>\nfrequ\u00eancia<\/th>\nvazamento de sinal<\/th>\ninterfere nos canais<\/th>\nobs<\/th>\n<\/tr>\n
1<\/td>\n2.412<\/td>\n401 – 423<\/td>\n2, 3, 4, 5<\/td>\nliberado mdp*<\/td>\n<\/tr>\n
2<\/td>\n2.417<\/td>\n405 – 428<\/td>\n1,3,4,5,6<\/td>\nliberado mdp<\/td>\n<\/tr>\n
3<\/td>\n2.422<\/td>\n411 – 433<\/td>\n1,2,4,5,6,7<\/td>\nliberado mdp<\/td>\n<\/tr>\n
4<\/td>\n2.427<\/td>\n416 – 438<\/td>\n1,2,3,5,6,7,8<\/td>\nliberado mdp<\/td>\n<\/tr>\n
5<\/td>\n2.432<\/td>\n421 – 443<\/td>\n1,2,3,4,6,7,8,9<\/td>\nliberado mdp<\/td>\n<\/tr>\n
6<\/td>\n2.437<\/td>\n426 – 448<\/td>\n2,3,4,5,7,8,9,10<\/td>\nliberado mdp<\/td>\n<\/tr>\n
7<\/td>\n2.442<\/td>\n431 – 453<\/td>\n3,4,5,6,8,9,10,11<\/td>\nliberado mdp<\/td>\n<\/tr>\n
8<\/td>\n2.447<\/td>\n436 – 458<\/td>\n4,5,6,7,9,10,11,12<\/td>\nliberado mdp<\/td>\n<\/tr>\n
9<\/td>\n2.452<\/td>\n441 – 463<\/td>\n5,6,7,8,10,11,12,13<\/td>\nliberado mdp<\/td>\n<\/tr>\n
10<\/td>\n2.457<\/td>\n446 – 468<\/td>\n6,7,8,9,11,12,13<\/td>\nliberado mdp<\/td>\n<\/tr>\n
11<\/td>\n2.462<\/td>\n451 – 473<\/td>\n7,8,9,10,12,13<\/td>\nliberado mdp<\/td>\n<\/tr>\n
12<\/td>\n2.467<\/td>\n461 – 483<\/td>\n8,9,10,11,13<\/td>\nliberado no Brasil e Europa<\/td>\n<\/tr>\n
13<\/td>\n2.472<\/td>\n–<\/td>\n9,10,11,12<\/td>\nliberado no Brasil e Europa<\/td>\n<\/tr>\n
14<\/td>\n2.484<\/td>\n–<\/td>\n–<\/td>\nliberado no Jap\u00e3o<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

* mdp: Maioria dos pa\u00edses<\/p>\n<\/div>\n

observa\u00e7\u00f5es<\/h1>\n

<\/p>\n

\n

O espa\u00e7amento na frequ\u00eancia entre os canais \u00e9 de apenas 5 Mhz<\/p>\n

O uso real da frequ\u1ebdncia por cada canal em redes 802.11b \u00e9 de 20 Mhz.<\/p>\n

O uso real da frequ\u00eancia por cada canal em redes 802.11g \u00e9 de 22 Mhz.<\/p>\n

Observe que o sinal de cada canal invade a faixa reservada dos canais anteriores e posteriores a sua frequ\u00eancia, \u00e9 assim que funciona, por isso recomenda-se utilizar canais mais espa\u00e7ados para evitar interfer\u00eancia.<\/p>\n<\/div>\n

redes<\/h2>\n
<\/div>\n

802.11b<\/h3>\n
\n

Canais default: 1, 6, 11<\/p>\n

Tipo de transmiss\u00e3o: DSSS<\/p>\n<\/div>\n

802.11g<\/h3>\n
\n

Canais default: 1, 6, 11<\/p>\n

Tipo de transmiss\u00e3o: OFDM<\/p>\n<\/div>\n

802.11n<\/h3>\n
\n

Canais default: 3, 11<\/p>\n

Tipo de transmiss\u00e3o: OFDM ou MIMO-OFDM<\/p>\n<\/div>\n

interfer\u00eancia<\/h2>\n
\n

Quando voc\u00ea tem redes operando na mesma frequ\u00eancia e em canais muito pr\u00f3ximos o que vai acontecer \u00e9 a diminui\u00e7\u00e3o da velocidade na tentativa de estabilizar o sinal.<\/p>\n

Em redes 802.11g ela vai diminuir – te\u00f3ricamente – de 54 para 48, 32, 24, 18, 12, 11, 9, 6, 5.5, 2 at\u00e9 1 Mbit.<\/p>\n

Na pr\u00e1tica a coisa \u00e9 bem diferente, devido overhead e interfer\u00eancias de sinal, a taxa de transmiss\u00e3o real de uma rede 802.11g estabiliza em torno de 27 Mbits.<\/p>\n

Lembro que essa velocidade nominal \u00e9 ainda dividida por cada cliente conectado no AP, se voc\u00ea tem 27 clientes, cada um ir\u00e1 trafegar no m\u00e1ximo a 1 Mbps.<\/p>\n

Em caso de espa\u00e7os muito pequenos se houver v\u00e1rios dispositivos utilizando o mesmo sinal, com pot\u00eancias diferentes, em canais muito pr\u00f3ximos os sinais podem ser anular, podemos chamar isso de ‘cancelamento m\u00fatuo’.<\/p>\n<\/div>\n

melhor cen\u00e1rio<\/h2>\n
<\/div>\n

802.11g<\/h3>\n
\n

Se precisamos usar 3 roteadores ou ap’s de forma simult\u00e2nea escolha os canais 1, 6 e 11 para minimizar a interfer\u00eancia.<\/p>\n

Se precisamos usar 4 roteadores ou ap’s de forma simult\u00e2nea escolha os canais 1, 4, 8 e 11 ou 1, 5, 9 e 11.<\/p>\n

Esses canais apesar de pr\u00f3ximos, dispostos nessa sequ\u00eancia, tendem a ter uma menor interfer\u00eancia.<\/p>\n<\/div>\n

802.11n (2.4 Ghz – 40 Mhz)<\/h3>\n
\n

Se precisar usar 2 roteadores use os canais 3 e 9 ou 3 e 11.<\/p>\n<\/div>\n

gr\u00e1ficos<\/h1>\n
<\/div>\n

canais<\/h2>\n
\n

\"\"<\/a><\/p>\n<\/div>\n

minimizando interfer\u00eancia<\/h2>\n
\n

\"\"<\/a><\/p>\n<\/div>\n

m\u00e1scara de espectro do sinal e canais<\/h2>\n
\n

\"\"<\/a><\/p>\n

 <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

objetivo Esclarecer d\u00favidas acerca de frequ\u00eancia, sinal e canais wifi em redes 802.11b e 802.11g. tabela informativa canal frequ\u00eancia vazamento de sinal interfere nos canais obs 1 2.412 401 – 423 2, 3, 4, 5 liberado mdp* 2 2.417 405 – 428 1,3,4,5,6 liberado mdp 3 2.422 411 – 433 1,2,4,5,6,7 liberado mdp 4 2.427 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[1,42,51,495,68,271,35],"tags":[593,594,592,591],"class_list":["post-858","post","type-post","status-publish","format-standard","hentry","category-viazap","category-leitura-recomendada","category-linux-linuxrs","category-profissional-de-ti","category-redes-2","category-seguranca-2","category-wireless","tag-canais","tag-interferencia","tag-sinal","tag-wifi"],"_links":{"self":[{"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=\/wp\/v2\/posts\/858","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=858"}],"version-history":[{"count":1,"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=\/wp\/v2\/posts\/858\/revisions"}],"predecessor-version":[{"id":859,"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=\/wp\/v2\/posts\/858\/revisions\/859"}],"wp:attachment":[{"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=858"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=858"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.clusterweb.com.br\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=858"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}