Has anyone said it yet - laying a 1/4 wavelength of wire out 'on the ground'
creates an (albeit somewhat lossy) open-endedquarter wave 'stub' of somewhat
indeterminate Z.
Recall, a quarter length away from the *open* end of a QW stubthe Z exhibits a
low Z value. This is tantamount to 'walking' halfway around the perimeter of
the Smith Chart (Z transformationor inversion in this case) and is the simple
application of "The Quarter Wave Rule" that any RF savvy engineer should 'take
tohis or her grave.
This is, BTW, a common trick (open-ended QW stub or microstrip 'line') used on
uWave MMICs to decouple Vgg and Vdd DC supply lines at millimeter wave lengths.
73,
Jim WB5WPA
From: Gerald Wolczanski <jerrywolczanski@earthlink.net>
To: rfi@contesting.com
Sent: Sunday, February 21, 2016 10:21 AM
Subject: [RFI] RFI cured with 1/4 wave wire
"RF ground"
OK - I get your point. When I say "RF ground" I mean a place for
antenna return currents to flow
Back to my original question:
"Why did the installation of a 1/4 wave wire attached to ground, at/near
the coupler, cure my 30 meter noise problem?"
My guess: It provided a low-Z ground at that frequency, not unlike a
"tuned ground"
as for:
http://www.k9yc.com/GroundingAndAudio.pdf
I see I have a "pin 1" problem (Elecraft K2) and probably numerous other
grounding/bonding things I need to look at. I will do that in the weeks
ahead, but right now, I'm clean as a whistle.
Jerry
KI4IO
Warrenton, VA
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