[RFI] Question about excess

Dave Cole (NK7Z) dave at nk7z.net
Wed Jan 10 08:59:49 EST 2018

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,

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 at 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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