[RFI] RFI Digest, Vol 157, Issue 31

[Wes Stewart]

The problem here is that both of you guys have changed the subject. The OP said he ran a 1/4 wire from the tuner to a tree  at "10 feet off the ground."
Now you have it on the ground and you're arguing about velocity factor and loss.

      From: "rfi-request at contesting.com" <rfi-request at contesting.com>
 To: rfi at contesting.com 
 Sent: Sunday, February 21, 2016 8:34 PM

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Message: 1
Date: Sun, 21 Feb 2016 16:56:21 -0800
From: Jim Brown <jim at audiosystemsgroup.com>
To: rfi at contesting.com
Subject: Re: [RFI] RFI cured with 1/4 wave wire
Message-ID: <56CA5CB5.9040105 at audiosystemsgroup.com>
Content-Type: text/plain; charset=utf-8; format=flowed

On Sun,2/21/2016 10:06 AM, JW via RFI wrote:
> 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.

WAY too lossy to be useful.

> 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.

Of course. But of what use is such a "stub" in this application? And, 
BTW, the Vp of the transmission line formed by the stub and the earth as 
a return is much less than 1. Resonance of radials is also shifted by 
their proximity to earth. Vp in the range of 0.7 is typical.

> 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.

Useful on PC boards, but I can't think of why it would be useful here.

73, Jim K9YC