[RFI] Shielding a ground wire

[Timo Toro]

The message from QRO contest stations to quiet reception and smooth 
operation is GROUNDING. I mean single point grounding. And cables 
between various devices are provided with ferrite chokes. (mix31?) I 
had similar RFI problems too.

If ground lead is quarter wave on 40m, as it was in my station, 
problems are welcome. I installed lots of copper outside the shack 
and good single point grounding inside. Lightning protection and RFI 
both are eased this way. Tuning the ground lead to series resonance 
on most problematic band, can help too. As was done in the example?, 
I sent earlier.

Taking GOOD care of lightning protection is not easy task, but that 
is the starting point.

To solve my PC PCI problem I used lots of ferrite between PowerMaster 
power meter display unit  and power sensing unit. Hard to believe, 
but there was pin one problem. Collected RF was then send to PC 
mother board via serial cable between PowerMaster and PC.

Grounding, grounding, single point grounding and lots of ferrite 
chokes everywhere! The more CPUs you have in your station the better 
grounding is needed.

73, Timo_oh5kw

At 15:59 -0700 27/4/13, Jim Brown wrote:
>On 4/27/2013 1:32 PM, Christopher Brown wrote:
>>But it is not a magic RF sink, and as far as the station 
>>goes.....station is second floor...strap or not, it is not a "RF 
>>ground" or some such for anything above 80M.
>
>Right. In general, a connection EARTH is NOT part of a solution to 
>RFI problems, nor does it make antennas work better (although it CAN 
>provide a current sink for a receiving antenna, the earth is FAR too 
>lossy to be an efficient part of a TX antenna).
>
>We MUST provide an effective earth connection for any premises, but 
>the reason for it is LIGHTNING SAFETY, not noise elimination.
>
>The only example I can think of where an earth connection CAN help 
>reduce noise is in combination with one or more common mode chokes 
>to shunt common mode current to the earth rather than a cable that 
>can either radiate it or couple it to an antenna feedpoint.
>
>73, Jim K9YC
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