Re: Detecting where a coax cable goes to

["Charlie Bress" <cbress@xxxxxxxxxxx>]

Good guess.
Wrong reason. The unterminated piece of cable, either open  or shorted,
creates a phenomenon called a standing wave. Depending on the length of the
offending cable and whether it is opened or shorted, the wave can raise the
dickens with the right signals. Terminating the cable in the correct
impedance doesn't let the standing wave be created.

Take a look at
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/Class/waves/u10l4b.html
It talks  about standing waves in a string, but the concept is similar for
liquids and radio waves.

Charlie

"BruceR" <br@xxxxxxxxxxxxxxxx> wrote in message
news:BUSAf.1305$Z3.347@xxxxxxxxxxxxxxxxxxxxxxx
> The center conductor of the coax is acts a small broadcast antenna (as
> well as a receiver) the outer shield serves to contain the signal on the
> center conductor to prevent both radiated signal leakage and reception of
> over-the-air signals. The exposed end of the cable or splitter connection
> is breaks the "seal" on the system and allows for leakage and reception of
> unwanted signals. The terminator acts like a lid on jar and maintains the
> cables impedance.
>
> From:bruno.lerer@xxxxxxxxx
> bruno.lerer@xxxxxxxxx
>
>> "> A caveat --
>>
>>> In a setup such as yours, each unused outlet should have a 75 ohm
>>> terminator.  Radio Shack has them.  Unterminated cables can mess up
>>> the signal to the active devices on the network.
>>
>>> SJF
>>
>> That goes for any unused connections on the spliter(s) as well. "
>>
>> Wow, for someone who is regulary considered by his friends as a more
>> or less maven, I now feel unbelievably ignorant ): I guess ignorance
>> is relative... I have never heard of 75 ohm terminators, nor of the
>> problems caused by unterminated cables and unused connections on
>> splitters.  As I mentioned in another response - learn something new
>> every day.
>
>