Re: Adding a third keypad to a Caddx NX-8, wiring help requested!

["petem" <petem001@xxxxxxxxx>]

"Karl Magnus" <magnus@xxxxxxxxxxxxxx> a écrit dans le message de news:
vuBNe.37819$rp.31847@xxxxxxxxxxxxxxxxxxxxxxxxx
>
>>
>>>Of course, they could be full of shit,
>>
>>
>> They are.
>>
>>
>
> Other types of wire you may need to know about include shielded, twisted,
> and stranded. Shielded wire traps and drains (among other things) RF
> interference and AC induction away from sensitive data circuits. Remember
> to ground only one side of the shield to an earth ground connection.
> Grounding both sides to the ground creates a giant dipole antenna and
> introduces damaging interference instead of draining it away. Twisted wire
> reduces the amount of interference, but just not as effectively as
> shielded.
>
> from: http://www.svconline.com/mag/avinstall_wiring_success/
>
> I guess they are also lying when they say this. "Twisted wire reduces the
> amound of interference...."
>

Twisted mean twisted pair or wire like in a cat5 cable each pair of wire is
twisted together..

this is not stranded wire..by the way,stranded wire is more flexible then
solid wire and that's the only difference..
on a same gauge of wire stranded or not there is no difference in how the
current/voltage of the signal in it will react..up to a certain frequency..

but the frequency where the difference start to be a problem is in the high
uhf band..

I know about this cause I work a lot with transmission line in my hobby(ham
radio)

the way twisted pair works,that helps sending data on long run,is
simple...if you run 2 wire side by side for long,there will be capacitive
effect that will form.the capacitance will affect the signal sent by
distorting it..

Now if you introduce the twisting of the pair will had a coiling effect,in
electronics class we learn that capacitance and inductance are inverse and
fighting each other...so the twisted pair cable will have a tendency to have
a controlled impedance what ever the length,that's in theory but it is
working a lot better then straight wire when sending data..

of course you have to be careful about the uses of twisted pair
wiring..cause its been known to engineer that build control panel that
simple JKT induce capacitance so they build there circuit to compensate
it..(adding inductance to it)

you can learn about capacitance here:
http://www.electronics-tutorials.com/basics/capacitance.htm

for inductance here:
http://www.electronics-tutorials.com/basics/inductance.htm

you can learn about the way current/voltage/frequency will react together
here: (reactance)
http://www.electronics-tutorials.com/basics/reactance.htm