[RFI] RFI cured with 1/4 wave wire

[David Harmon]

Years ago....this is how I resolved a TV raster problem on 80mtrs from my own TV.
I used RG-6 and laid it on the floor....it was much less than 1/4 wave though.


73

David Harmon
K6XYZ
Sperry, OK


-----Original Message-----
From: RFI [mailto:rfi-bounces at contesting.com] On Behalf Of JW via RFI
Sent: Sunday, February 21, 2016 12:07 PM
To: rfi at contesting.com
Subject: Re: [RFI] RFI cured with 1/4 wave wire


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 at earthlink.net>
 To: rfi at 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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