[RFI] DirecTV systems

[David C. Cole]

Hi Jim,

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.  

I would expect this RF to be able to radiate...  Maybe not well, but
some...  Is it that the levels are so low that the radiation is not
detectable?  Remember the source RF is in the 2 through 30 MHz spectrum,
right on the ham bands...


On Thu, 2013-03-28 at 10:15 -0700, Jim Brown wrote: 
> On 3/28/2013 9:52 AM, David C. Cole wrote:
> > 1.  Make sure all splitters have termination on unused ports.
> > 2.  Make sure all items are grounded as per code.
> > 3.  Make sure all cable connections are tight as can be.
> 
> Of these, I would place the greatest emphasis on #3.  With respect to 
> #2, the real issues are
> 
> Termination of the cable shield at each end to the shielding enclosure, 
> NOT directly to the circuit board;
> 
> and
> 
> bonding together of all grounds within the premises by short, fat 
> copper.  That includes, but is not limited to, telco, CATV, satellite, 
> power, ham antennas, and lightning protection.
> 
> I see no relevance to his #1 with respect to RFI. The real issues are 
> his #3 and the cable shield issue (The Pin One Problem), both of which 
> are well known causes of both ingress and egress with systems of all sorts.
> 
> 73, Jim K9YC
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