Cristi YO3FFF wrote:
From Terman (as Richard Fry mentioned):
http://i62.photobucket.com/albums/h85/rfry-100/TermanFig55.jpg
First hop distance on E layer reflection for given angles is:
20 degrees = 300miles, 30 degrees = 200miles
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But note that Terman shows much longer
Cristi,
Thank you for the thoughtful answer.
If I was of a mind to verify the use of probes, I would look at the
attenuation slope of sample signal from a distance source across the area
being measured and carefully record that slope. THIS DOES NOT require a
calibrated instrument to a
On 10/3/2012 7:20 AM, Tom W8JI wrote:
I would agree with your idea about multiple points making it
meaningful if you also moved the probes deep below ground, to a depth
where the field diminished to unimportant values. I think this is a
case of not being able to do things right, so we dismiss
Hello all,
I like to share my experiments and hear from your similar experiments regarding
ground conductivity and permittivity measurements.
As we all know (should know), those two parameters are esential to evaluate the
ground under our antennas, especially for verticals.
The ideea to
As we all know (should know), those two parameters are esential to evaluate
the ground under our antennas, especially for verticals.
The ideea to measure the ground concuctivity and permittivity rise after I
read Rudy's (N6LF) article, Measurement of soil electrical parameter at
HF.
I use the
On 10/2/2012 3:31 AM, cris blak wrote:
The less ground conductivity the higher is the antenna elevation radiation
angle.
Excellent work, Cristi. A suggestion for this last part of the
analysis. Rather than look at the vertical angle where the radiation
peaks, look at the field strength at
Excellent work, Cristi. A suggestion for this last part of the analysis.
Rather than look at the vertical angle where the radiation peaks, look at
the field strength at some chosen low angle, like 10 degrees for various
soil conditions. Now, we can see a dB value.
But, we're not done there.
Richard Fry, you know anything about this? A 5:1 change in soil seems way
out of line with what I recall from fields at WSPD on 1370 kHz and WOHO on
1470 kHz. Were those stations exceptions?
I don't know about further out where you'd have to proof an AM station
but I just ran some models and
I don't know about further out where you'd have to proof an AM station
but I just ran some models and there's kind of a weird relationship
between vertical electric field strength at 1 wavelength out and far
field efficiency as ground conductivity is varied for fixed
permittivity.
One
Conclusion: The less ground conductivity the higher is the antenna
elevation radiation angle. This is a negative impact for DX!
Cris, Tom, Paul et al
This belief is common when looking at the far-field elevation pattern of a
vertical monopole in MoM results, or in antenna textbooks. That
Hi Richard,
On your referenced fields graph you caption Measured vs. Calculated
intensity, but the traces are not differentiated. Which traces on the
graph are measured and which are calculated?
73, Guy.
On Tue, Oct 2, 2012 at 2:58 PM, Richard Fry r...@adams.net wrote:
Conclusion: The less
On your referenced fields graph you caption Measured vs. Calculated
intensity, but the traces are not differentiated. Which traces on the graph
are measured and which are calculated?
The chart at the top of the page contains only data calculated by NEC.
The chart titled
, October 02, 2012 2:58 PM
Subject: Re: Topband: Ground conductivity, permittivity measurement
Conclusion: The less ground conductivity the higher is the antenna
elevation radiation angle. This is a negative impact for DX!
Cris, Tom, Paul et al
This belief is common when looking at the far-field
On 10/2/2012 11:30 AM, Tom W8JI wrote:
I was wondering if ground rods were ever correlated to a known way of
determining soil conductivity.
See Rudy's work, on his website.
73, Jim K9YC
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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