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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