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Re: [RFI] Question about excess

To: rfi@contesting.com
Subject: Re: [RFI] Question about excess
From: "Dave Cole (NK7Z)" <dave@nk7z.net>
Date: Wed, 10 Jan 2018 05:59:49 -0800
List-post: <mailto:rfi@contesting.com>
Hi Wes,

Given your location in the desert-- the low number of homes close to you, and your having your antenna 100 feet away from your shack, it is no big surprise that you don't have a lot of local RFI. Lucky man!

However therein lies the key... Your antenna is 100 feet away from your RFI generating home. Not all of us have that luxury...

My vertical is about 50 feet from the house, (which makes me lucky), while my dipole is about 15 feet from the house...

Coiling the excess cable from wallwarts within the house made a rather significant difference, (as expected), in the number and strength of the many SMPS birdies I had when on the dipole, and all but eliminated them when on the vertical.

I use mix31 clamp on ferrite material, put about 8 turns on one ferrite, clamp it shut, and if I have more slack, I use a second ferrite. The hand-wringing you see is because some of us have serious issues with antenna systems close to our homes...

73s and thanks,
Dave
NK7Z
http://www.nk7z.net

On 01/09/2018 02:51 PM, Wes Stewart via RFI wrote:
Coil 'em up or bundle 'em up and throw a tie wrap around 'em, or leave them 
dangle and stop worrying about it.

IMHO, there is far too much hand wringing about this stuff. The only CM chokes in my station 
are molded onto the cables supplied by the computer and monitor suppliers and the one outside 
at the feedpoint of my inverted-vee. It"s one of those "low-performance" W2DU 
types.

If I use a handheld HF radio to sniff up close to the clothes washer and dryer, 
the fridge, the dishwasher, the induction cooktop, the computer monitors and TV 
sets, the wall warts, etc, I hear garbage.  I hear none of it using the HF 
antennas on the tower a 100' away.  On 160 using the TX Inverted-L on receive I 
still hear more than I can work with 500W.

Wes  N7WS
.
  Date: Mon, 8 Jan 2018 19:33:44 -0700
  From: Greg Newberry <greg@obillow.com>

  Hello all,
I've been following the forum for a
  while and learning a great deal
  about RF, RFI, etc. So I'm in the
  process of cleaning up my ham shack.
  Putting in a SPG (single point ground)
  and in general, being pro-active
  about RFI.
One thing I'm not sure of; what should
  I do with the excess length of
  power cords. i.e. A 6ft cord on my
  computer, but it's only two feet to
  the outlet. Extra length on wall warts,
  audio cables etc. ?
Coil them up, bunch them up? I don't
  really want to cut them all down to
  length, as I do move things around.
Thanks in advance,
  Greg
  WB7DUO
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