Lub teeb liab jammer jamming nrug muaj feem xyuam rau cov cuab yeej RF putput zog, Kav hlau txais xov Gain thiab ib puag ncig ib puag ncig ect.
A. Lub teeb liab jammer Ntaus RF tso zis hluav taws xob thiab kav hlau txais xov zoo ib yam, Hauv qhov chaw dav dav jamming nrug yuav nyob deb dua tom qab ntawd Hauv tsev ib puag ncig.
B. Yog hais tias ib puag ncig ib puag ncig zoo ib yam, RF tso zis hluav taws xob ntau dua, qhov sib nrug deb yuav deb dua.
C. Directional antenna jamming distance will farther then omini antenna,
Omini kav hlau txais xov omnibearing 360 degree.
Directional kav hlau txais xov kev taw qhia yog pem hauv ntej.
1.Base Chaw Nres Tsheb: Lub hauv paus chaw nres tsheb yog qhov chaw nres tsheb hauv xov tooj ntawm pej xeem, yog ib daim ntawv xov tooj cua thiab hais txog lub xov tooj cua xa xov tooj cua uas xa cov ntaub ntawv ntawm lub xov tooj ntawm tes thiab lub xov tooj ntawm tes hauv ib cheeb tsam xov tooj cua.
Base station to transmit power 45DBM calculation, the plain area in around two kilometers the basic signal strength of-95DBM, three kilometers at the basic no signal.
2. Environment: Such as atmosphere, obstacle, signal strength, Multipath etc,it will caused transmission distance loss.
3. Interference blocker jammer: Lub teeb liab jammer qhov tseeb yog cov khoom siv hluav taws xob tiv thaiv hluav taws xob, txhawm rau ua kom cov yeeb ncuab cov khoom siv hluav taws xob thiab cov tshuab poob lossis txo cov txiaj ntsig ntawm kev cuam tshuam hauv xov tooj cua. Nws yog ib qho tseem ceeb ntawm kev tawm tsam hauv hluav taws xob, Lub hom phiaj yog kom tsis muaj zog lossis rhuav tshem cov yeeb ncuab siv ntau yam khoom siv hluav taws xob thiab cov tshuab ua kom muaj kev sib ntaus sib tua, kev sib ntaus sib tua, kev sib txuas lus thiab kev tswj hwm riam phom thiab kev taw qhia ntawm lub peev xwm.
Los ntawm lub tsev qauv ntawm phab ntsa tom qab lub block pib ho attenuate (ib phab ntsa feem ntau 10 15dB)
The bomb Jammer each module RF output power is 50W, ,Jamming distance depend on the signal strength environment. for mobile signal strength if in -50dBm, distance maybe short, if Signal strength in -85dBm, it will can jamming 100m, if signal strength in -95dBm, It can jamming 250m.
4. RF Output power 2W=33dBm 10W=4dBm 50W=47dBm, 100W=50dBm. Each additional 3dBm, Power will be doubled.
5. Raws li hauv qab no qhia txog cov txheej txheem ntawm kev xam qhov kev ncua deb ntawm kev sib txuas lus wireless thaum qhov chaw pub dawb raug xa mus. Qhov no -hu ua qhov chaw propagation yog hais txog kev nthuav tawm ntawm cov xov tooj cua nyob ib ncig ntawm lub kav hlau txais xov, uas yog qhov zoo tshaj plaws propagation mob. Thaum cov nthwv dej nthuav tawm hauv qhov chaw dawb, lawv lub zog tsis tau nqus los ntawm kev cuam tshuam los yog cuam tshuam los yog tawg.
Qhov kev sib txuas lus nyob deb yog cuam tshuam nrog lub zog xa tawm, kev txais tos rhiab heev thiab kev ua haujlwm zaus.
Lfs(dB)=32.44 plus 20lgd(km) plus 20lgf(MHz)
Nyob rau hauv cov mis, Lfs yog kis tau tus mob poob, d yog kis tau tus mob nyob deb, thiab chav tsev ntawm zaus yog xam MHz. Nws tuaj yeem pom los ntawm qhov sib npaug saum toj no tias yoj propagation poob (tseem hu ua attenuation) nyob rau hauv qhov chaw dawb tsuas yog cuam tshuam rau kev khiav hauj lwm zaus f thiab qhov kev nthuav tawm deb d, thiab thaum f lossis d yog ob npaug, Lfs yuav nce 6 dB. , raws.
Cov qauv hauv qab no qhia txog qhov poob ntawm xov tooj cua tshaj tawm hauv qhov chaw dawb
Los=32.44 plus 20lg d(Km) plus 20lg f(MHz)
Los is the propagation loss the unit is dB
d is the distance, the unit is Km
f is the operating frequency, the unit is MHz
Cov piv txwv hauv qab no qhia txog kev ua haujlwm zaus ntawm 433.92MHz, lub zog xa tawm ntawm ntxiv rau 10 dBm (10mW), qhov tau txais rhiab heev ntawm -105dBm system hauv qhov chaw pub dawb tshaj tawm:
1. Lub zog xa hluav taws xob yog ntxiv rau 10 dBm thiab kev txais tos rhiab heev yog -105 dBm
Los = 115dB
2. Los, f
Calculated d = 30 km
Qhov no yog qhov zoo tshaj plaws kev sib kis deb, daim ntawv thov tiag tiag yuav qis dua tus nqi, qhov no yog vim qhov kev sib txuas lus wireless yuav raug rau ntau yam sab nraud, xws li cua, teeb meem, multipath tshwm sim los ntawm kev poob, kev poob ntawm cov siv tus nqi rau hauv cov qauv saum toj no, koj tuaj yeem xam qhov kwv yees ntawm kev sib txuas lus.
Piv txwv tias atmospheric, occlusion thiab lwm yam poob los ntawm 25dB, tuaj yeem xam los ntawm kev sib txuas lus:
D=1.7 km
Conclusion: The transmission loss is reduced by one for every 6 dB increase, wireless transmission loss twice
wireless transmission loss every 6 dB increase, transmission distance reduce twice
