[RFI] DirecTV systems

[David C. Cole]

Hello Jim,

Thanks for the explanation...  I will go unterminate one and see what
happens...  I would expect some radiation from it, but you are probably
correct, not enough wire to radiate it...  

On Thu, 2013-03-28 at 10:57 -0700, Jim Brown wrote: 
> On 3/28/2013 10:44 AM, David C. Cole wrote:
> > I would expect that a mismatch on one port, (i.e. no termination), would
> > cause RF on that port, as things would become unbalance inside the
> > splitter thus removing the prefect isolation between ports that should
> > exist with matched impedances.
> 
> No, because there's nothing connected to it to radiate. Think about it 
> -- WIRES radiate when they carry RF current. No wire, no current, no 
> radiation. Likewise, coax radiates ONLY when it carries common mode 
> current (outside the coax), not differential current (inside the coax), 
> or when the shield is degraded, open, or of poor quality.
> 
> The only effects of an unterminated port are a slightly higher (a dB or 
> two, depending on the number of ports) and some reflections on the other 
> ports, the strength of which would also depend on the number of ports. .
> 
> 73, Jim K9YC
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