[Elecraft] Now General RF Issue WAS 160m loop experiment a big failure

[Jim Brown]

On 10/20/2011 6:21 PM, goldtr8 at charter.net wrote:
> I apparently have a bigger problem with RF in the shack and it has
> nothing to do with the loop.

Hi Don,

Your email, and some of the solutions offered, reflect some common 
misconceptions about RFI, including an earth connection as a solution 
(it is NOT), and SWR as a cause (it is NOT).  The usefulness of noting 
changes from the original SWR values is that it tells you SOMETHING HAS 
CHANGED in the antenna, so that you know to go looking for something 
that is broken.

I strongly suggest that you download and study my tutorial on RFI for 
Hams. Nearly all problems blamed on "RF in the shack" are really caused 
by Pin One Problems in equipment where the RF is detected, and by 
antenna systems that put RF on the outside of the coax.

Study   http://audiosystemsgroup.com/RFI-Ham.pdf

One question to ask is, "What ELSE, besides that coax, might have 
changed between before when everything worked, and now, when I have 
RFI."  Think about cable connections between equipment in the shack that 
might be acting as antennas to bring that RF that your antennas are 
radiating into the equipment.  And think about this -- your antennas 
SHOULD be putting a lot of RF in your shack -- they must do this if they 
are working as antennas. Any cables connected to your equipment will act 
as receiving antennas. When equipment has a Pin One Problem, the RF 
current those antennas (interconnect cables) receive will flow into your 
equipment.

Sometimes you can modify equipment to correct the Pin One Problem, but 
usually the better fix is simply make the cables a lousy RX antenna by 
adding a common mode choke to them. That's what you're doing when you 
wind some turns of the cable through a ferrite cores.

Study the tutorial to understand this. And when I say "study" I mean 
STUDY, don't just read it through once.

73, Jim Brown K9YC