More info on the
By Al Merriman
hcdx list, July 10-11, 1999
Some answers to questions about K9AY Loops:
If you only wish to cover one or two directions a single loop
will work just fine.
When I did my initial testing with these antennas I temporarily
hung a single loop from a tree in the front yard.
Per the original article and per my experiments a 9:1 transformer
works best, at least for coverage of long and medium wave.
Claims have been made by others that a 4:1 transformer will provide
marginally better signals on short wave, but it has been my experience
that the 9:1 works well there also.
If you live in an isolated and extremely quiet area with no local
close in noise sources such as televisions, computers, powerlines,
your neighbors light dimmer, etc the transformer described in
the original QST article will work well.
If you're like most of us, and don't have that luxury, I would
suggest a "magnetic" type transformer, where there is no direct
connection between the antenna and feedline. This can make a real
difference in minimizing local noise pests.
Information on transformers of this type is available
from the National Radio Club reprints. Their reprint A69 "Noise
& Interference Reducing Antennas" is available from: National
Radio Club, Publications Center, P O Box 164, Mannsville, N Y
Price for members in USA/Canada is $1.50; non-members USA/Canada
$2.00, and all other countries $2.20 via airmail.
Martin: Do K9AY loops work as well as an
EWE antenna? Are they as directional?
Beyond reading two articles about these in QST and a bit of hearsay
concerning their performance I have no experience with the EWE
In what I've written I've stated several times that F/B nulls
approaching 40db are common with the K9AY's - does the EWE do
One thing that I've heard several times about the EWE is that
their performance is affected by slight changes in ground conductivity
such as during rain, etc. If this is true - and I don't know that
it is - this is one area where the two systems are radically different
as the K9AY's require very little in the way of a ground and are
not affected in the least by rain, etc - at least as far as I've
been able to tell in a year of use.
To get max performance from the EWE I'm sure you would need a
remotely tuned variable termination which should be fairly easy
to implement using the twisted pair wire for the antennas like
Steve Byan uses with his beverages.
Martin: Do you point the antenna in the direction you want
to receive, or is the input pointed in the direction you want
Main pickup by the K9AY's is from the feedline end towards the
terminated end - just the opposite of a terminated beverage.
Martin: Do you have a length that works the best for MW?
Per the original article antenna length should be "not much more
than 1/4 wavelength at the highest frequency of interest".
This means that antennas up to 150 feet in length - and maybe
just a bit more should give full LW/MW coverage including the
X-band as a full wavelength at 1700 kHz is almost 600 feet.
My loops are 90 feet in length and with a 15db preamp give signal
levels comparable to my slopers that are approximately 60 feet
high at the high end and 150 long.
in Europe who are interested in these antennas, but do not
want to build their own, Andy Ikin of Wellbrook Communications
has these for sale. Andy can be reached at
Wellbrook has a firm policy of no sales to North America. I'm
not sure what the current policy is to the rest of the world.
You can contact Andy for availibility and price and if you do
so I would appreciate it if you would mention my name.