{"id":33117,"date":"2019-10-31T21:50:51","date_gmt":"2019-10-31T18:50:51","guid":{"rendered":"https:\/\/prohoster.info\/blog\/chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv\/"},"modified":"2019-10-31T21:50:51","modified_gmt":"2019-10-31T18:50:51","slug":"chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/administrirovanie\/chto-slyshno-v-radioefire-prinimaem-i-dekodiruem-naibolee-interesnye-signaly-chast-2-ukv","title":{"rendered":"Co se d\u011bje v r\u00e1diov\u00e9m \u00e9teru? P\u0159\u00edjm\u00e1me a dek\u00f3dujeme nejzaj\u00edmav\u011bj\u0161\u00ed sign\u00e1ly. \u010c\u00e1st 2, VKV","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Ahoj, Habr.<\/p>\n

V prvn\u00ed \u010d\u00e1sti<\/a><\/noindex> byly pops\u00e1ny n\u011bkter\u00e9 sign\u00e1ly, kter\u00e9 lze p\u0159ijmout na dlouh\u00fdch a kr\u00e1tk\u00fdch vln\u00e1ch. Ne m\u00e9n\u011b zaj\u00edmav\u00fd je rozsah VKV, na kter\u00e9m tak\u00e9 m\u016f\u017eete naj\u00edt n\u011bco zaj\u00edmav\u00e9ho.<\/p>\n

\"Co
\nStejn\u011b jako v prvn\u00ed \u010d\u00e1sti se budeme zab\u00fdvat t\u011bmi sign\u00e1ly, kter\u00e9 lze samostatn\u011b dek\u00f3dovat pomoc\u00ed po\u010d\u00edta\u010de. Kdo m\u00e1 z\u00e1jem, jak to funguje, pokra\u010dov\u00e1n\u00ed pod \u010dl\u00e1nkem.
\n<\/a><\/noindex>
\nVe prvn\u00ed \u010d\u00e1sti jsme pou\u017eili nizozemsk\u00fd online p\u0159ij\u00edma\u010d<\/a><\/noindex> k p\u0159ij\u00edm\u00e1n\u00ed dlouh\u00fdch a kr\u00e1tk\u00fdch vln. Bohu\u017eel, pro VKV nejsou obdobn\u00e9 slu\u017eby \u2014 rozsah frekvenc\u00ed je p\u0159\u00edli\u0161 velk\u00fd. Proto ti, kdo cht\u011bj\u00ed zopakovat n\u00ed\u017ee popsan\u00e9 experimenty, si budou muset po\u0159\u00eddit vlastn\u00ed p\u0159ij\u00edma\u010d, z t\u011bch nejlevn\u011bj\u0161\u00edch lze zm\u00ednit RTL SDR V3<\/a><\/noindex>, kter\u00fd lze zakoupit za 30 $. Tento p\u0159ij\u00edma\u010d pokr\u00fdv\u00e1 rozsah a\u017e 1,7 GHz, v\u0161echny n\u00ed\u017ee popsan\u00e9 sign\u00e1ly byly p\u0159ijaty pr\u00e1v\u011b na n\u011bj. <\/p>\n

Tak tedy, za\u010dneme. Stejn\u011b jako v prvn\u00ed \u010d\u00e1sti, budeme sign\u00e1ly zkoumat podle vzestupu frekvence.<\/p>\n

FM r\u00e1dio<\/h2>\n

\nSamo FM r\u00e1dio asi nikoho nep\u0159ekvap\u00ed, n\u00e1s v\u0161ak bude zaj\u00edmat RDS. P\u0159\u00edtomnost RDS (Radio Data System) zaji\u0161\u0165uje p\u0159enos digit\u00e1ln\u00edch dat \u201euvnit\u0159\u201c FM sign\u00e1lu. Spektrum sign\u00e1lu FM stanice po demodulaci vypad\u00e1 takto:<\/p>\n

\"Co
\n
\nNa frekvenci 19 kHz je um\u00edst\u011bn pilotn\u00ed t\u00f3n, a na jeho trojn\u00e1sobn\u00e9 frekvenci 57 kHz je p\u0159en\u00e1\u0161en sign\u00e1l RDS. Na oscilogramu, pokud se oba sign\u00e1ly vykresl\u00ed spole\u010dn\u011b, to vypad\u00e1 zhruba takto:<\/p>\n

\"Co
\n
\nPomoc\u00ed f\u00e1zov\u00e9 modulace je zde zak\u00f3dov\u00e1n n\u00edzkofrekven\u010dn\u00ed sign\u00e1l s frekvenc\u00ed 1187,5 Hz (mimochodem, frekvence 1187,5 Hz byla tak\u00e9 vybr\u00e1na n\u00e1hodn\u011b \u2014 je to frekvence 19 kHz pilotn\u00edho t\u00f3nu d\u011blen\u00e1 16). D\u00e1le, po bitov\u00e9m dek\u00f3dov\u00e1n\u00ed, jsou roz\u0161ifrov\u00e1ny datov\u00e9 pakety, jejich\u017e typ\u016f je pom\u011brn\u011b mnoho \u2014 krom\u011b textu mohou b\u00fdt p\u0159en\u00e1\u0161eny nap\u0159\u00edklad alternativn\u00ed frekvence vys\u00edl\u00e1n\u00ed rozhlasov\u00e9 stanice, a p\u0159i vjezdu do jin\u00e9 oblasti se p\u0159ij\u00edma\u010d m\u016f\u017ee automaticky naladit na novou frekvenci. <\/p>\n

P\u0159ijmout RDS data m\u00edstn\u00edch stanic lze pomoc\u00ed programu RDS Spy<\/a><\/noindex>. Lze jej p\u0159ipojit p\u0159es HDSDR, pokud vyberete modulaci FM, \u0161\u00ed\u0159ku sign\u00e1lu 120 kHz a bitov\u00fd tok 192 kHz, jak je uk\u00e1z\u00e1no na obr\u00e1zku.<\/p>\n

\"Co
\n
\nPak sta\u010d\u00ed p\u0159esm\u011brovat sign\u00e1l pomoc\u00ed Virtual Audio Cable z HDSDR na RDS Spy (v nastaven\u00ed VAC je tak\u00e9 t\u0159eba nastavit bitrate na 192 kHz). Pokud bylo v\u0161e provedeno spr\u00e1vn\u011b, uvid\u00edme v\u0161echny informace o RDS, mnohem v\u00edce ne\u017e uk\u00e1\u017ee b\u011b\u017en\u00fd dom\u00e1c\u00ed p\u0159ij\u00edma\u010d:<\/p>\n

\"Co
\n
\nKrom\u011b FM lze tak\u00e9 dek\u00f3dovat DAB+, o tom byla samostatn\u00e1 \u010dl\u00e1nek<\/a><\/noindex>. V Rusku prozat\u00edm nefunguje, ale v jin\u00fdch zem\u00edch to m\u016f\u017ee b\u00fdt aktu\u00e1ln\u00ed.<\/p>\n

Leteck\u00fd p\u00e1smo<\/h2>\n

\nTak historicky vzniklo, \u017ee v letectv\u00ed se pou\u017e\u00edv\u00e1 amplitudov\u00e1 modulace (AM) a frekven\u010dn\u00ed p\u00e1smo 118-137 MHz. Rozhovory pilot\u016f a dispe\u010der\u016f nejsou nijak \u0161ifrov\u00e1ny, a p\u0159ijmout je m\u016f\u017ee kdokoliv. P\u0159ed 20 lety pro to \"p\u0159itahovali\" b\u011b\u017en\u00e9 levn\u00e9 \u010d\u00ednsk\u00e9 p\u0159ij\u00edma\u010de \u2013 sta\u010dilo roz\u0161\u00ed\u0159it c\u00edvky heterodinu, a p\u00e1smo se posunulo, pokud m\u00e1te \u0161t\u011bst\u00ed, tak sm\u011brem k vy\u0161\u0161\u00edm frekvenc\u00edm. Z\u00e1jemci o \"digit\u00e1ln\u00ed archeologii\" mohou p\u0159e\u010d\u00edst diskuzi na f\u00f3ru radioscanner<\/a><\/noindex> z roku 2004. Pozd\u011bji \u010d\u00edn\u0161t\u00ed v\u00fdrobci vy\u0161li vst\u0159\u00edc u\u017eivatel\u016fm a jednodu\u0161e p\u0159idali p\u00e1smo Air do p\u0159ij\u00edma\u010d\u016f (v koment\u00e1\u0159\u00edch k prvn\u00ed \u010d\u00e1sti doporu\u010dovali Tecsun PL-660 nebo PL-680). Ale samoz\u0159ejm\u011b, pou\u017eit\u00ed specializovan\u011bj\u0161\u00edch za\u0159\u00edzen\u00ed (nap\u0159\u00edklad p\u0159ij\u00edma\u010d\u016f AOR, Icom) je mnohem v\u00fdhodn\u011bj\u0161\u00ed \u2013 maj\u00ed potla\u010den\u00ed \u0161umu (zn\u011bj\u00edc\u00ed se vypne, kdy\u017e sign\u00e1l nen\u00ed a nen\u00ed st\u00e1l\u00fd \u0161um) a vy\u0161\u0161\u00ed rychlost prohled\u00e1v\u00e1n\u00ed frekvenc\u00ed.<\/p>\n

Ka\u017ed\u00e9 velk\u00e9 leti\u0161t\u011b pou\u017e\u00edv\u00e1 pom\u011brn\u011b hodn\u011b frekvenc\u00ed, nap\u0159\u00edklad frekvence leti\u0161t\u011b Pulkovo, p\u0159evzat\u00e9 ze str\u00e1nky radioscanner:<\/p>\n

\"Co
\n
\nMimochodem, m\u016f\u017eete poslouchat p\u0159enosy rozhovor\u016f z r\u016fzn\u00fdch rusk\u00fdch m\u011bst (Moskva, S-Pb, \u010celjabinsk a n\u011bkter\u00e9 dal\u0161\u00ed) online na http:\/\/live.radioscanner.net<\/a><\/noindex>. <\/p>\n

Pro n\u00e1s v leteck\u00e9m p\u00e1smu je zaj\u00edmav\u00fd digit\u00e1ln\u00ed protokol ACARS<\/a><\/noindex> (Aircraft Communications Addressing and Reporting System). Jeho sign\u00e1ly se p\u0159en\u00e1\u0161ej\u00ed na frekvenc\u00edch 131.525 a 131.725 MHz (evropsk\u00fd standard, frekvence r\u016fzn\u00fdch region\u016f se mohou li\u0161it<\/a><\/noindex>). Jsou to digit\u00e1ln\u00ed pakety s bitrate 2400 nebo 1200 bps, pomoc\u00ed takov\u00e9ho syst\u00e9mu mohou piloti vym\u011b\u0148ovat zpr\u00e1vy s dispe\u010derem. Pro dek\u00f3dov\u00e1n\u00ed v MultiPSK je t\u0159eba nastavit na sign\u00e1l v re\u017eimu AM (pot\u0159ebn\u00fd SDR p\u0159ij\u00edma\u010d, proto\u017ee \u0161\u00ed\u0159ka p\u00e1sma sign\u00e1lu je v\u00edce ne\u017e 5 kHz) a p\u0159esm\u011brovat zvuk pomoc\u00ed Virtual Audio Card. <\/p>\n

V\u00fdsledek je zn\u00e1zorn\u011bn na screenshotu.<\/p>\n

\"Co
\n
\nForm\u00e1t sign\u00e1l\u016f ACARS je relativn\u011b jednoduch\u00fd a lze jej zobrazit v programu SA Free. Sta\u010d\u00ed otev\u0159\u00edt fragment z\u00e1znamu a uvid\u00edme, \u017ee \u201euvnit\u0159\u201c AM z\u00e1znam\u016f se ve skute\u010dnosti nach\u00e1z\u00ed frekven\u010dn\u00ed modulace.<\/p>\n

\"Co
\n
\nD\u00e1le, aplikov\u00e1n\u00edm frekven\u010dn\u00edho detektoru na z\u00e1znam snadno z\u00edsk\u00e1me bitov\u00fd tok. V re\u00e1lu je nepravd\u011bpodobn\u00e9, \u017ee by to bylo pot\u0159ebn\u00e9, proto\u017ee hotov\u00e9 programy pro dek\u00f3dov\u00e1n\u00ed ACARS ji\u017e d\u00e1vno existuj\u00ed.<\/p>\n

Meteosatelity NOAA<\/h2>\n

\nPo poslechu jedn\u00e1n\u00ed pilot\u016f se m\u016f\u017eeme dostat je\u0161t\u011b v\u00fd\u0161e \u2014 do vesm\u00edru. Zde n\u00e1s zaj\u00edmaj\u00ed meteosatelity NOAA 15<\/a><\/noindex>, NOAA 18<\/a><\/noindex> a NOAA 19<\/a><\/noindex>, kter\u00e9 vys\u00edlaj\u00ed obr\u00e1zky povrchu Zem\u011b na frekvenc\u00edch 137.620, 137.9125 a 137.100 MHz. Sign\u00e1l lze dek\u00f3dovat pomoc\u00ed programu WXtoImg<\/a><\/noindex>.<\/p>\n

P\u0159ijat\u00fd obr\u00e1zek m\u016f\u017ee vypadat p\u0159ibli\u017en\u011b takto (foto z webu radioscanner):<\/p>\n

\"Co
\n
\nBohu\u017eel (fyzik\u00e1ln\u00ed z\u00e1kony nelze p\u0159elst\u00edt a Zem\u011b je kulat\u00e1, i kdy\u017e v to ne v\u0161ichni v\u011b\u0159\u00ed), sign\u00e1l satelitu lze p\u0159ijmout pouze tehdy, kdy\u017e let\u00ed nad n\u00e1mi, a ne v\u017edy maj\u00ed tyto lety pohodln\u00fd \u010das a \u00fahel nad obzorem. D\u0159\u00edve, aby bylo mo\u017en\u00e9 zjistit \u010das a datum nejbli\u017e\u0161\u00edho letu, bylo nutn\u00e9 nainstalovat program Orbitron<\/a><\/noindex> (program dlouhov\u011bk\u00fd, existuj\u00edc\u00ed ji\u017e od roku 2001), nyn\u00ed je to jednodu\u0161\u0161\u00ed ud\u011blat online p\u0159es odkazy https:\/\/www.n2yo.com\/passes\/?s=25338<\/a><\/noindex>, https:\/\/www.n2yo.com\/passes\/?s=28654<\/a><\/noindex> a https:\/\/www.n2yo.com\/passes\/?s=33591<\/a><\/noindex> odpov\u00eddaj\u00edc\u00edm zp\u016fsobem. <\/p>\n

Sign\u00e1l satelit\u016f je dost siln\u00fd a je sly\u0161iteln\u00fd prakticky na jakoukoli ant\u00e9nu a jak\u00fdkoli p\u0159ij\u00edma\u010d. Aby bylo mo\u017en\u00e9 p\u0159ijmout obr\u00e1zek v dobr\u00e9 kvalit\u011b, je v\u0161ak \u017e\u00e1douc\u00ed m\u00edt speci\u00e1ln\u00ed ant\u00e9nu a dobr\u00fd v\u00fdhled na obzor. Ti, kte\u0159\u00ed maj\u00ed z\u00e1jem, se mohou pod\u00edvat na anglick\u00fd tutori\u00e1l na YouTube<\/a><\/noindex> nebo si p\u0159e\u010d\u00edst podrobn\u00e9 popisy<\/a><\/noindex>. Osobn\u011b jsem ale nem\u011bl trp\u011blivost dov\u00e9st v\u011bc do konce, ale jin\u00fdm to mo\u017en\u00e1 p\u016fjde l\u00e9pe.<\/p>\n

Pagingov\u00e9 zpr\u00e1vy FLEX\/POCSAG<\/h2>\n

\nZda pagingov\u00e1 komunikace pro korpor\u00e1tn\u00ed klienty v Rusku st\u00e1le funguje, to nev\u00edm, v Evrop\u011b v\u0161ak funguje zcela norm\u00e1ln\u011b, pou\u017e\u00edvaj\u00ed ji hasi\u010di, policie a r\u016fzn\u00e9 slu\u017eby. <\/p>\n

Sign\u00e1ly FLEX a POCSAG lze p\u0159ijmout pomoc\u00ed HDSDR a Virtual Audio Cable, pro dek\u00f3dov\u00e1n\u00ed je pou\u017eit program PDW<\/a><\/noindex>. Ten byl naps\u00e1n ji\u017e v roce 2004 a rozhran\u00ed m\u00e1 odpov\u00eddaj\u00edc\u00ed, ale jak divn\u00e9, st\u00e1le funguje.<\/p>\n

\"Co
\n
\nExistuje tak\u00e9 dekod\u00e9r multimon-ng, kter\u00fd funguje pod Linuxem, jeho\u017e zdrojov\u00e9 k\u00f3dy jsou dostupn\u00e9 na githubu<\/a><\/noindex>. O protokolu p\u0159enosu POCSAG byla tak\u00e9 naps\u00e1na samostatn\u00e1 studie, z\u00e1jemci si ji mohou p\u0159e\u010d\u00edst podrobn\u011bji.<\/a><\/noindex>.<\/p>\n

Kl\u00ed\u010dence\/bezdotykov\u00e9 vyp\u00edna\u010de<\/h2>\n

\nNa frekvenci 433 MHz se nach\u00e1z\u00ed cel\u00e1 \u0159ada r\u016fzn\u00fdch za\u0159\u00edzen\u00ed \u2014 bezd otykov\u00e9 vyp\u00edna\u010de a z\u00e1suvky, zvonky, senzory tlaku pneumatik automobil\u016f a dal\u0161\u00ed. <\/p>\n

\"Co
\n
\n\u010casto se jedn\u00e1 o levn\u00e9 \u010d\u00ednsk\u00e9 za\u0159\u00edzen\u00ed s nejjednodu\u0161\u0161\u00ed modulac\u00ed. Nen\u00ed zde \u017e\u00e1dn\u00e9 \u0161ifrov\u00e1n\u00ed a pou\u017e\u00edv\u00e1 se jednoduch\u00fd bin\u00e1rn\u00ed k\u00f3d (OOK \u2014 on-off keying). Dek\u00f3dov\u00e1n\u00ed takov\u00fdch sign\u00e1l\u016f bylo prob\u00edr\u00e1no v samostatn\u00e9m \u010dl\u00e1nku<\/a><\/noindex>. M\u016f\u017eeme v\u0161ak vyu\u017e\u00edt hotov\u00fd dekod\u00e9r rtl_433, kter\u00fd si lze st\u00e1hnout odsud<\/a><\/noindex>. <\/p>\n

\"Co
\n
\nPo spu\u0161t\u011bn\u00ed programu je mo\u017en\u00e9 vid\u011bt r\u016fzn\u00e1 za\u0159\u00edzen\u00ed a (p\u0159i p\u0159\u00edtomnosti parkovi\u0161t\u011b) zjistit nap\u0159\u00edklad tlak v pneumatik\u00e1ch sousedova automobilu. Z praktick\u00e9ho hlediska to nem\u00e1 moc v\u00fdznam, ale z \u010dist\u011b matematick\u00e9ho pohledu je to docela zaj\u00edmav\u00e9 \u2014 protokoly t\u011bchto sign\u00e1l\u016f jsou jednoduch\u00e9 k dek\u00f3dov\u00e1n\u00ed.<\/p>\n

Mimochodem, ti, kte\u0159\u00ed kupuj\u00ed takov\u00e9 bezd otykov\u00e9 vyp\u00edna\u010de, by m\u011bli m\u00edt na pam\u011bti, \u017ee v\u016fbec nejsou chr\u00e1n\u011bn\u00e9, a teoreticky v\u00e1\u0161 hacker-soused s HackRF nebo podobn\u00fdm za\u0159\u00edzen\u00edm m\u016f\u017ee zlovoln\u011b vypnout sv\u011btlo v koupeln\u011b v nejm\u00e9n\u011b vhodn\u00fd okam\u017eik nebo ud\u011blat n\u011bco podobn\u00e9ho. Osobn\u011b se t\u00edm netr\u00e1p\u00edm, ale pokud je ot\u00e1zka bezpe\u010dnosti aktu\u00e1ln\u00ed, lze vyu\u017e\u00edt seri\u00f3zn\u011bj\u0161\u00ed a dra\u017e\u0161\u00ed za\u0159\u00edzen\u00ed s plnohodnotn\u00fdmi kl\u00ed\u010di a autentizac\u00ed (Z-Wave, Philips Hue apod.).<\/p>\n

TETRA<\/h2>\n

\nTETRA<\/a><\/noindex> (Terrestrial Trunked Radio) \u2014 je to profesion\u00e1ln\u00ed syst\u00e9m podnikov\u00e9 radiokomunikace s dostate\u010dn\u011b velk\u00fdmi mo\u017enostmi (skupinov\u00e9 hovory, \u0161ifrov\u00e1n\u00ed, propojen\u00ed n\u011bkolika s\u00edt\u00ed apod.). A jej\u00ed sign\u00e1ly, pokud nejsou \u0161ifrovan\u00e9, lze tak\u00e9 p\u0159ij\u00edmat pomoc\u00ed po\u010d\u00edta\u010de a SDR p\u0159ij\u00edma\u010de.<\/p>\n

Dekod\u00e9r TETRA pro Linux existoval u\u017e pom\u011brn\u011b dlouho<\/a><\/noindex>, ale jeho nastaven\u00ed bylo daleko nen\u00e1ro\u010dn\u00e9, a asi p\u0159ed rokem vytvo\u0159il rusk\u00fd program\u00e1tor plugin pro p\u0159\u00edjem TETRA<\/a><\/noindex> pro SDR#. Nyn\u00ed je tento \u00fakol \u0159e\u0161en t\u00e9m\u011b\u0159 doslova ve dvou kliknut\u00edch, program umo\u017e\u0148uje zobrazovat informace o syst\u00e9mu, poslouchat hlasov\u00e9 zpr\u00e1vy, shroma\u017e\u010fovat statistiky apod.<\/p>\n

\"Co
\n
\nPlugin nezahrnuje v\u0161echny mo\u017enosti standardu, ale z\u00e1kladn\u00ed funkce v\u00edce m\u00e9n\u011b funguj\u00ed.<\/p>\n

Podle Wikipedie m\u016f\u017ee b\u00fdt Tetra pou\u017eita v ambulanc\u00edch, policii, na \u017eeleznici apod. O jej\u00edm roz\u0161\u00ed\u0159en\u00ed v Rusku nic nev\u00edm (p\u0159edpokl\u00e1d\u00e1m, \u017ee s\u00ed\u0165 Tetra byla pou\u017eita na MS2018, ale to nen\u00ed jist\u00e9), z\u00e1jemci si mohou ov\u011b\u0159it sami \u2014 sign\u00e1ly Tetra jsou snadno rozpoznateln\u00e9 a maj\u00ed \u0161\u00ed\u0159ku 25 kHz, jak je vid\u011bt na screenshotu. <\/p>\n

Samoz\u0159ejm\u011b, pokud je v s\u00edti aktivov\u00e1no \u0161ifrov\u00e1n\u00ed (takov\u00e1 mo\u017enost v Tetra existuje), plugin nebude fungovat \u2014 m\u00edsto \u0159e\u010di bude pouze \u201ebubl\u00e1n\u00ed\u201c.<\/p>\n

ADSB<\/h2>\n

\nVystoup\u00edme je\u0161t\u011b v\u00fd\u0161e na frekvenci, na frekvenci 1,09 GHz jsou p\u0159en\u00e1\u0161eny sign\u00e1ly transponder\u016f letadel, co\u017e umo\u017e\u0148uje web\u016fm jako FlightRadar24 zobrazovat p\u0159eletuj\u00edc\u00ed letadla. Tento protokol byl ji\u017e d\u0159\u00edve probr\u00e1n, tak\u017ee se zde nebudu opakovat (\u010dl\u00e1nek se i tak vyda\u0159il velk\u00fd), z\u00e1jemci si mohou p\u0159e\u010d\u00edst prvn\u00ed<\/a><\/noindex> a druhou<\/a><\/noindex> \u010d\u00e1sti.<\/p>\n

Z\u00e1v\u011br<\/h2>\n

\nJak je vid\u011bt, i s p\u0159ij\u00edma\u010dem za 30 dolar\u016f lze ve vzduchu nal\u00e9zt spoustu zaj\u00edmav\u00e9ho. Jsem si jist\u00fd, \u017ee to, co je zde uvedeno, rozhodn\u011b nen\u00ed v\u0161e a n\u011bco jsem asi p\u0159ehl\u00e9dl nebo nev\u00edm. Z\u00e1jemci to mohou zkusit sami \u2014 je to dobr\u00fd zp\u016fsob, jak l\u00e9pe porozum\u011bt principu fungov\u00e1n\u00ed t\u00e9 \u010di on\u00e9 s\u00edt\u011b.<\/p>\n

Amat\u00e9rskou r\u00e1diovou komunikaci jsem nezva\u017eoval, i kdy\u017e na VKV tak\u00e9 existuje, ale \u010dl\u00e1nek je p\u0159ece jen o slu\u017eebn\u00ed komunikaci.<\/p>\n

P.S.: Speci\u00e1ln\u011b pro kulhackery<\/a><\/noindex> lze poznamenat, \u017ee v otev\u0159en\u00e9m \u00e9teru se u\u017e asi 50 let nep\u0159en\u00e1\u0161\u00ed nic skute\u010dn\u011b tajn\u00e9ho, tak\u017ee z \u201etohoto\u201c pohledu byste nem\u011bli pl\u00fdtvat \u010dasem a pen\u011bzi. Z hlediska studia princip\u016f komunikace a r\u016fzn\u00fdch in\u017een\u00fdrsk\u00fdch syst\u00e9m\u016f je ale seznamov\u00e1n\u00ed se skute\u010dnou prac\u00ed re\u00e1ln\u00fdch s\u00edt\u00ed naopak velmi zaj\u00edmav\u00e9 a pou\u010dn\u00e9.
\n
Zdroj: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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