[Elecraft] kxpa100 remoting

[Jim Rogers]

IF the twisted pairs are fed with differential drivers, then the noise 
is "common mode" and cancels itself out.  A simple TTL circuit over 
twisted pair will still be quite vulnerable to RFI.  Been there done 
that for many, many, years in datacomm.

Jim, W4ATK
On 8/7/2014 10:22 PM, Jim Brown wrote:
> On 8/7/2014 6:52 PM, bill.va3ol at gmail.com wrote:
>> Has anyone tried unshielded cable?; Cat 5E cable?;or whatever!
>
> All of the unshielded CATx cables have very good immunity to external 
> RF and noise if each signaling circuit is carried by one of the 
> twisted pairs. The CATx cable carries RS232, which requires two pairs. 
> The two remaining pairs connect the key line and logic circuit (ACC2).
>
> In general, a high quality twisted pair is far more important than a 
> cable shield ff the CATx cable is properly wired (that is, one pair 
> for each signalling circuit). The primary advantage of is higher CAT 
> spec is reduced crosstalk between pairs, which is a big deal for 
> Ethernet, but much less so for applications like this.
>
> 73, Jim K9YC
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