Guy Atkins wrote:
Hi Dallas,

I've been curious about your noise-reducing antennas some time, so this past
weekend I decided to build one as accurately as possible per your design. I
first got interested these antennas in the early 1990s during some e-mail
exchanges with Denzil Wraight in Germany.

I used the 3:1 turns ratio in the antenna transformer, and 18 ga. twinlead
speakerwire between it and the 1:1 transformer. The top of the 45 ft.
vertical is suspended to a branch in a tall tree, and the bottom end
fastened to a 5-ft. copper pipe in the ground. The antenna is located about
60 feet from the house, and my Wellbrook ALA 100 is 40 feet from the house.

I was quite surprised find not just worse noise from the vertical, but MUCH
worse noise. Signal levels seem good, but the noise is so bad the
readability suffers greatly, compared to the loop. For instance, this
morning past sunrise I was hearing JOAK in Tokyo on 594 kHz with an S-3
signal in Japanese, coming in nicely on the loop. However, the same
frequency on the vertical was just a strong BUZZZZZ of light-dimmer type
QRM. This was the most pronounced of the comparisons, but in most cases of
checking frequencies up through HF, the loop was the outright winner. I
tried to record 594 khz for comparisons, but I was using my modded R-75 and
didn't have the recording software configured properly since my last
DXpedition, and my SDR-1000 isn't fully hooked up at the moment. So, I
wasn't able to make a quick recording before the signal faded with
increasing daylight.

I did find a couple signals on the tropical bands where the vertical
provided a stronger signal with equal noise pickup (so therefore better S/N
than the loop).

However, my main interest right now is foreign MW signals. Do you have any
tips for improving this antenna's noise rejection on MW?

I can only think of two things that might impact the performance here. I
used the same type of binocular core ferrites that W8JI recommends, as I
have a lot of them. You used a traditional torroid form. Also, I don't know
how good the ground needs to be for this antenna to work well; the single
5-ft pipe may not be sufficient (soil here is reasonably good, though, clay
mixed with organic material...it's a forest floor).

Thanks in advance for any ideas!

Guy Atkins
Puyallup, WA
www.sdr-1000.blogspot.com

I have found that a single ground point,ie "standard" 8' AC mains
ground ro, are
at best very marginal. And the lower the frequency, as a general rule,
the "bigger"
the ground should be. Hams often use radials.

Think of the classic dipole. It has two arms. The classic vertical
"monopole"
needs a very good, ie low RF resistance, grounds. At the very least I
would
try for a set of 3 6' ground rods seperated from each other by at least
6'.

I think I may have gone overboard with a whole house perimeter ground
ring,
but I was given the copper tubing and a friend used a small Ditch Witch
to
dig the trench.

Did the improved ground make a difference over the discribed set of 3
rods?
There is a 10W TIS station in Winchester that I couldn't receive on my
70'
"long" wire antenna with a R2000. I tried a, as near as I could build
it, identical
ground set up and wire antenna at about the same height, from a
friend's
home who is about 5 miles closer and who has a lower RF background
noise floor and I think I could detect the carrier in SSB.

Maybe your soil is unusualy conductive and a 5' rod will suffice, but I
suspect
that a better, ie more complete, ground system will help all of your
non
dipole antennas.

And exception to the "good" set of 3 ground rod "rule" is with the
Lankford
Active Antenna, AKA AMRAD, which will operate very nicely on a single
8' ground rod driven so that 2' remain above ground for a mounting
base.

With a Lankford Active Dipole no ground is required. I have tried one
with
and without the 6'/2' ground rod. And it worked very well both ways. At
some frequencies the grounded operation was a little quiter. Of course
with
any active antenna great care should be taken to insure that common
noise
mode noise doesn't go up the braid and enter the antenna. The Dipole
configeration is much less sensitive to common mode, but it attention
to
detail will be rewarded. The best single refference I have found is the
"Common Mode Choke" PDF by W1HIS. I don't have the link handy,
but I have given the link several times.

A call to your local utility and/or a MW broadcaster can often get you
valid
information on local ground conductivity conditions. I did notice that
on the
coldest days last winter, when the temp droped to below 0F, where my
older
ground lost some effficeincy from the ground freezing, my new, super
ground never varried. And this summer during the drier, though to be
fair this
was hardly a dry summer, periods my ground stayed effective.

I am not really into NDB or MW DX but I can report that the improved
ground
really made a lot more NDBs receivable, and I found a lot more garbage
stations on MW. A simpler super ground that we installed for Will, a
new
SWL that I am helping, consisted of a 1/4" copper tube that is about
20'
long and connects his "SW" ground to the AC/Mains/Telco/SatDish ground.
Lowered his noise by several S-units on a DX398 all across LW/MW and
lower
SW bands. He used a funky flat shovel to open a slot about 6" deep. I
would
have prefered deeper, but it was his home, copper and effort.

Terry