BNC Terminator

[rodan]

Which BNC terminator would be better? The " 50-Ohm 1% 1/2W ", or, the " 50-Ohm 5% 1/2W "? I don't understand what the percentages mean.

 

[ScottMac]

The percentage is the allowed tolerance (or deviation) from the specified value.

If you have 50 Ohm terminators (usually just resistors), and you measure them with a meter, they should be plus-or-minus the percentage of tolerance (a 50 ohm terminator with a 5% tolerance could measure +/- 2.5 ohms and still be in spec, if it was rated for 1%, then it would have to no more than +/- .5 ohm).

Closer tolerances usually cost more.

Deviation on the coax is going to be variable, depending on the existance of kinks, twists, bends, pinches, compression, containants, etc...but if the cable was laid out straight & perfect, you'd probably have between 1%-5% deviation along the length of the (average). Some manufacturers built better cable (closer to spec / less overall deviation), but they usually charge more for it.

Anyway..there ya go (before I slide too far OT).

FWIW

Scott

 

[rodan]

Wow, Ok. I think. So, I would choose the BNC terminator, based on the quality of BNC cable I have, and, how it's laid?( kinks, etc) If length matters, I have a 25 foot piece, and, a ten foot piece. Relatively, cheap, basic, BNC cable. Could I use either the 1 percent, or the 5 percent terminator? Or, a better question, IF the 1 percent is better, will it work on any BNC cable?

 

[ScottMac]

Either would work fine. The length and quality of the cable probably don't require anything closer than 5%.

Just because the terminator is rated at 5% doesn't mean it's that far off, but "it could be."

(Don't for get to ground one end of that coax, if you're using it for Ethernet)

Good Luck

Scott

 

[rodan]

How do I ground one end? Here is what I'm doing: I'm networking just two computers together, Peer to Peer, with Windows 98SE on both computers. Using ISA ethernet cards, PNP. These cards have BNC connectors. I'm putting T - connectors on them, with the BNC terminators at the open ends of the "T" on both computers. I understand I do need to use terminators at the ends of the network, which, in this case is only two computers, so, I would use them at both ends. So, how do I ground one end of my eithernet connection?

 

[ScottMac]

Some flavors of terminators have a grounding wire or lug (or chain) attached.

Don't try to solder a wire to a terminator. The heat from the soldering iron cooks the carbon in the resistor and changes the value.

Good Luck

Scott

 

[rodan]

I ordered a couple of BNC terminators, so, I should look for a grounding wire or lug, attached to it. Do I just run this grounding wire, to a screw on my pc case? For instance, just ground it to a screw that holds the power supply, or, the cover for the case? IF the terminators do not have a grounding wire, or lug, attached to it, I will be sure not to solder one on, I guess I can figure out a way, to attach a wire to it, somehow. Thank you.