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Home » Forums » Forum Archives » Networking and Internet Sharing » Topic # 1733

bnc/utp network problem
dream_v Feb-26-02 06:17 PM
i have this network configuration: internet gateway -> UTP cable -> 100Mbps (16 UTP ports) switch (10 Windows computers) -> UTP cable -> 10Mbps (8 UTP ports + 1 BNC) hub (3 Windows computers) -> RG58 cable (10base2 - about 130 meters) -> 10Mbps (8 UTP ports + 1 BNC) hub -> UTP cable -> 1 Windows computer.
the last Windows computer cannot connect to the rest of the network. no signal.
the RG58 cable is ok, the BNC connectors, BNC Tee and BNC terminators are ok, but still no communication. no link between hubs.
is something wrong with my RG58 backbone?

1. RE: bnc/utp network problem
lbyard Feb-27-02 01:01 AM
In response to message 0
>the RG58 cable is ok, the BNC connectors, BNC Tee and BNC terminators are ok

How do you know they are? Larry


2. RE: bnc/utp network problem
dream_v Feb-27-02 05:53 PM
In response to message 1
>the RG58 cable is ok, the BNC connectors, BNC Tee and BNC terminators are ok
>How do you know they are? Larry


i made mesurements with an ohm-meter at each end. with and without terminators. without hubs.

results:
terminators - 50 ohm
tee - nothing
cable without terminators - nothing

cable with terminator at one end (head A) - 70 ohm at the other end (head B)

cable with both terminators - 30 ohm at each end

cable lenght - about 130 meters

voltage at each hub BNC port - about 9 volts

a friend tell me i must use a repeater for RG58 cable over 100 meters lenght. but i know the 10Base2 cannot exceed 185 meters not 100 meters!


3. RE: bnc/utp network problem
lbyard Feb-28-02 12:48 PM
In response to message 2
>i made measurements with an ohm-meter at each end. with and without terminators.

A continuity check (DC ohms) of a network cable is no guarantee that the cable is good and will operate at radio frequencies. For example, the cable could be kinked or flattened somewhere along itís length and still test good with an ohmmeter. If you do not have a network tester (they are expensive, or at least they were when I bought one years ago), I would suggest attaching a PC at each end of that particular cable segment to test it. http://duxcw.com/faq/network/thinwire.htm. Larry


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