[Elecraft] Common Mode chokes to reduce noise

[Ed Cole]

OK, kind of what I was thinking.  So either go on search for noise 
source or try reducing the noise at the receiver.  K3 NB does not 
improve SNR on 6m.

On HF noise varies: 80m its S7 from an inverted-V; on 20m its S3 from a 
yagi (both have baluns).

6m noise at S5-S7 is the most troublesome because I do weak-signal 
operating (eme, ms, FT8). InnovAntenna 6m baluns are many ferrite beads 
in series.  6m yagis are LFA7 from InnovAntenna (UK).

Shack is grounded via No. 8 wire to ground post adjacent to shack. 
Aluminum plate coax thru-wall panel is grounded by it, as well.

ED-KL7UW
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If it does, something is very wrong in your shack, like bonding. What
DOES matter is having effective common mode chokes at the antenna's
feedpoint. See my recommendations at k9yc.com/publish.htm

73, Jim K9YC
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I don't see how a common mode choke would help in that situation. If the
noise changes that dramatically depending upon where you have the
antenna pointed, that strongly suggests that the noise is being received
by the antenna and is not riding on the shield of the coax.? If it is
received by the antenna it is differential in nature and a common mode
choke won't do anything.

It sounds like you are being plagued by either a local noise source, or
the atmospheric noise is much stronger in one direction.? In my case,
the background noise during the middle of the day is always stronger
east versus west even though there isn't any significant housing or
businesses within 200 miles east of me.

73,
Dave?? AB7E