Thanks to all that have given tips on this. I was using a Fluke 77 in
the low resistance automatic range and as Lee K7TJR pointed out even a
small induced voltage was enough to drive the resistance reading up to
20K Ohms. I made additional measurements with my Sperry DM-4100 and an
analog VOM and they were all different. On the DC scale I measured .6
volts om respect to ground. this would be enough to sent the Fluke
nuts. When using the Sperry's diode settings I got -.243 in one
direction and no reading in the other. Maybe I was going nut or Tesla's
theories of extra scalar potential are really valid. Tomorrow I will run
out a line cord and take along a 12VAC transformer and feed the two
wires of the Beverage against ground while measuring the actual return
voltage.
Then I will calculate the voltage drop of the sire to ground loop and
calculate the resistance. I know this may sound crude but I should get
a more usable value. what had me worries about the far end 3 ground rod
termination is that between wires the resistance measurably 40 ohms for
a 900 foot Beverage which should be fine. I guess since the WD-1A is a
balance medium any induced voltage would be cancelled out. There is a 3
phase 14KVA system that passed parallel to the road near where the
Beverages are terminated maybe there is enough DC rectified currents
somewhere to give me the false reading on my Fluke.
My initial test results suggested that the far end ground connection was
gone but that was not the case. Wading my way through waist high saw
grass for 900 feet trips is not fun. My son came up with a excellent
suggestion of buying a quad copter with video on e Bay and making my
Beverage wire inspection will siting in the shack. As anyone every
tried that? Sounds like fun. Plodding thorough waist deep snow in the
winter, not a problem here, is a not a very easy chore.
Herb, KV4FZ
On 11/15/2016 12:55 PM, Lee STRAHAN wrote:
Hello Herb and fellow Top Banders,
When I had Beverage antennas here I was never able to read the ground
resistance here as well. The reason it did not work here is there was actually
a small DC voltage difference between grounds apparently developed by galvanic
means or currents in the earth. This voltage does not allow a DC resistance
meter to read correctly.
As a side note there is a 1,000,000 volt DC power generation line running
from Celilo Oregon to Sylmar California that uses the Earth as one conductor.
Its no wonder here there is DC across portions of the ground. Just look up
Celilo converter station if you are curious. 3200 megawatts transported from
Oregon to California through the ground! This line is within 20 miles of my
farm. This may or may not be partly responsible for the DC difference on mine
or others Beverage antennas.
Lee K7TJR OR
I have reflection transformers at the end of every two wire Beverages which I
try to test by measuring the wires on the feed end. I remove the transformer
from the two wire WD1-A and check the resistance between the two wires which
tells me that through the reflection transformer I have continuity. It measures
about 40 ohms wire to wire, this is done when I notice any performance change
of the antenna. Now come the next test that baffles me completely. When I
measure from either wire to my ground rods alone, to see what the return
resistance is, I get reading
in the vicinity of 20K across the 900 foot run. I understand that if
the reading was very low it would defeat the whole Beverage principle.
But is 20K Ohms reasonable, very good, or marginal? I use three foot foot rods
at either end and when I pull one out yesterday before moving it the bottom 1/4
was moist and muddy. That Southern end of several reversible Beverages is
located about 100 feet or less from a salt marsh or salt pond. I also have to
such antennas made up of ladder line a DX Engineering components. They all
appear to be working well even though large grass has reach and covered portion
of some of them.
But my question is what is a reasonable or good return ground resistance for a
600' or 900' Beverage. I haven't found any sources of information expect the
saying that the higher Resistance the better. Is this correct?
Herb Schoenbohm, KV4FZ
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