This is just a brief first impression of the new Wellbrook K9AY
antenna trhat I am in the process of evaluating. I LOVE IT! Since we
have returned to Oklahoma 10 days ago, I've managed to erect both the
older first generation ALA100-based Phased Array and the
all-new K9AY version. Both arrays incorporate twin Delta Loops with
the two loops 40 meters apart. I erected the two arrays parallel to
each other, pointing due North-South for evaluation they are
separated by about 300 feet, so there is little chance of interaction.
I've just spent two evenings running the two arrays, but I'm
seriously in love. The ALA100 array has been my antenna of choice for
the past three seasons and has been a wonder. The K9AY Array is even
better, especially for domestic DXers.
Similarities in the two Arrrays:
Both have two 40 meter apart small delta antennas, the antennas are
amplified at the head unit in each case
Both phase their two elements against each other to achieve very deep
nulls that are instantly swappable fore and aft at the shack (very
important for domestic DXers and sometimes trans-oceanic ones.)
Both units can be easily expanded to operate two separate arrays so
that one may cover all four cardinal directions, N, S, E, and West...
or any two angles, since the two 2-antenna arrays are NOT
interdependent. I'm actually running the two different arrays with
one controller in the shack.
Both units were/are quite expensive (they are multi-unit Phased
Arrays, after all)
Differences:
The K9AY array has a narrower front lobe (the ALA100 Array is,
functionally, a full 180 degrees wide) This should help both in S/N
ratio and in giving very different views of the band in each of four
directions.
The K9AY array has deeper nulls so deep that they may not be
fully measurable here in the winter, even at solar noon. EZNEC
predicts about 5 to 10 dB deeper than the already deep 45 dB nulls of
the ALA100 array.
The K9AY sports somewhat larger loop (base of each Delta is about 30
feet, where the ALA100 unit base is about 20+ feet.) and the
amplifier is technically even better and about 10 dB stronger.
The K9AY requires good grounding at each antenna element for best
performance; the older ALA100 unit required no grounding.
Early Results:
I used my very accurate Winradio for these tests. HOWEVER, I paid no
attention to the S-meter after peaking up the null before checking a
frequency.
One test was at the lower part of the band from 540 through 730. I
maximized the null against the dominant southerly or northerly and
then reversed the array. I did this for each array, about 15 or 20
seconds apart. There were 20 channels examined in that range (540
through 730.) On 15 of the channels, I marked something like Much
clearer on the K9AY or Much better on the K9AY and, on virtually
every channel, there was one station looking north and another
looking south, at least on the K9AY. One channel, 600, I marked
ALA100 seems better and on one... 620 with Dallas and CKRM, the two
antennas both performed equally well. The remaining three were inconclusive.
A couple of interesting notes: WWLS in Norman on 640 is one of my
semi-local pests. It is nearly impossible to completely null it with
the ALA100 Array, especially at night. The K9AY Array nailed it. WLS
on 700 is off to the ENE and not nullable with this set-up, however,
I had a strong Mexican beneath on the K9AY and nothing on the ALA100
Array. I also snuck up to mid-bander 930, my favorite rock and roll
station 50 years ago and a local pest that is VERY difficult to null
with any antenna. I had CJCA to the North mixing with residual WKY on
the ALA 100, but CJCA alone and stronger on the K9AY array. WONDERFUL!
.
On the upper part of the band, I just looked at 1600 to 1500 and the
K9AY Array was superior here, too. 1600- had Cedar Rapids and
Mexico, with the K9AY superior; 1590 was inconclusive as was 1580.
1570 was my old buddy growing up, XERF. The K9AY was superior, but
there was nothing identifiable in the null. 1560 was inconclusive;
1550, 1540, 1530, 1520, 1510 and 1500 each showed the K9AY Array
clearly superior! So three channels were inconclusive, due most
likely to station locations and seven had the K9AY Array as the star.
1520 is worthy of special mention: that is the old rock and roll
50,000 watts of KOMA, 50 miles due south of me, now a talker as KOCY,
I think. It and 50,000 w - 740 KRMG in Tulsa, an equal distance to my
east, is my worst nemesis. I have never been able to null KOMA-1520
with any antenna that I have ever usaed. KOMA is the only station
that I had ever received here on 1520 until two nights ago. The
K9AY Array put KOMA in the mud about 90% of the time and I heard
WHOW, Clinton, Illinois-1520 along with at least one other station
with almost no KOMA remaining.
I have yet to do any daytime test comparisons of the antennas or more
formal evaluations,
