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Comunicatii in tunel


Gabriel_S
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Salutare,Zilele trecute aflandu-ma ca de obicei in metrou la orele diminetii am ajuns accidental pe 148.025Mhz unde am receptionat pe toata distanta dintre Piata Muncii si Crangasi o purtatoare peste care aparea ocazional modulatie FM...respectiv discutii intre dispecerat si trenurile de metrou aflate pe traseu...intrebarea e daca stie cineva cum functioneaza acest sistem si cum se fac legaturi radio in tunel? :nas: 73!

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Acele legaturi radio se fac prin radiatie RF pe liniile de distributie tensiune.Pe langa acestea au si o platbanda din cupru (ca mediu purtator RF) neconectata la capete si care serveste pentru transmisia si receptia semnalelor RF in tunel. (a fost montata special pentru asa ceva)In alta ordine de idei alcelasi lucru se petrece si in aer liber daca doi corespondenti (cu statiile) stau sub liniile de joasa sau inalta tensiune (cu conditia ca intre cei doi corespondenti cu radiotelefoane sa nu existe statii de transformare).In acest fel se dubleaza sau chiar tripleaza distanta de comunicatie dintre cele doua statii radio.Liniile de transport energie electrica se comporta in acest caz ca un mediu de retransmisie pentru undele RF.

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