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[IRCA] Wellbrook Arrays at Grayland (was re: Day ONE @ Grayland)
At 05:17 PM 10/31/2009 -0500,Neil Kazaross wrote:
(SEE MY RESPONSE BELOW - Bryant) : This is good news about the
arrays. Once again I will stress that I think end fire arrays of two
cardioid antennas will be a major step forward for those with the
room to use them (home users need a good sized yard) and whom are
only interested in one general direction.
I presume that you were using Wellbrook components for both
arrays? My appologies to all for not yet testing the 2 KAZ (delta
flag) array here. My bad back has returned and is becoming chronic
once again. I can cope with the pain to lay out wires on the ground
and phasing them, but getting up a ladder to trees for cardioid
antennas is currently out of the question.
Anyhow..I am so happy to see you guys testing two loops !!! I presume
that both these arrays are basically set and forget and give great
back end nulls across the entire band? If so then there's all sort of
interesting possibilities for pattern improvements..ie more narrow
main beam or phasing something out off to the side of the main beam
if you phase one array vs the other (although I think you'd space
them further than 150 feet apart)
Hmmm Russia clobbering KGO 810.. that sounds like awesome F/B to
me! Your Chinese logging on 900 past Victoria indicates a rather
narrow beamwidth as well !
Looking to read more.. 73 KAZ
Bryant's reply:
Kaz,
Really sorry to hear that your back is acting up again. I know from
personal experience how persistent and debilitating those things can
be. I'm sure that Andy Ikin is anxious to get your insight on his new
FLG100 antenna and two loop array, but I'm certain that he
understands. As it happens, I'm ending up doing some of the
evaluation in your stead.... mostly from necessity.
I'm just amazed at the progress in antenna design that has been made,
mostly by Andy and Wellbrook, but also some others working on their
own and Dallas Lankford teaming up with Guy Atkins. The first step in
this whole revolution was the growing appreciation of large,
broadband single turned loops, vertically, as antennas. The Wellbrook
ALA100, still an exceptional antenna, was one of the prominent
commercial versions of that movement. The advantage in noise
rejection, relatively small footprint and relative stealthiness made
it a real winner for DXers on small urban and suburban lots. Its
classic wide figure-of-8 pattern was an advantage in many
applications and a weakness only for DXers desiring either much
narrower lobes or a cardoid, uni-directional pattern (or both). I'd
guess that the ALA100 will be a staple in Wellbrook's lineup for many
years to come.
As phasing developed over the years, most of the work (Misek,
Connelly) focused on combining signals from two long wire antennas,
usually Beverages until the last decade, or so. Most phasers were
also designs that required at least tweaking at each frequency of
interest. DXers did and still do amazing things with that technology.
Three things excited me about Andy's original phased array: a) the
fact that it was broadband, basically allowing the DXer to "set and
forget" b) the fact that it was based on two small ALA100 loops,
excellent antennas themselves, arranged in a fairly small footprint
and c) that it was reversible with the flick of a switch. One array
of two loops could cover the horizon, but two pairs (N, S, E, W)
cloudy really cover the horizon. I loved that array and found that it
equaled or surpassed the short 600' and 900' Beverages that I
routinely deploy at Grayland. That original ALA-100 Array is still
the best antenna in some limited situations, IMHO. That is the
antenna that I've used for the past 30 months or so and I still love it.
The other interesting line of development in recent years has been
the broadly-based development of a whole stable of DIRECTIONAL
single-turn broadband loops. At this point, I don't really remember
whether the EWE, the Flag or the Pennant came first, soon to be
followed, of course, by the KAZ. Anyway, with those antennas,
individually 15 dB or more of F/B ratio, I guess that it was just a
matter of time until Andy (and surely others soon) to combine
broadband phasing with already directional loops. Andy says that he
has gotten over 50 dB F/B in field tests. I've not yet gotten to that
range, but I'm restricted here by poor ground, rocky terrain, cliffs,
etc. I'm sure that I'll get better that 50 dB in some configurations
when I get back to my cow pasture in Oklahoma in another month or so.
As I understand it, Andy has brought out two new DIRECTIONAL single
loop antennas and two new Arrays, each based on one of those new loop
designs. What I have here is four K9AY loop heads. With the right
base units in the shack, each would be a separate REVERSIBLE K9AY
directional loop. Using the biggest Phased Loop Array controller, you
can phase and reverse two phased pairs of k9AYs. With the tighter
front lobe achieved by phasing K9AY pairs, it takes two pairs to come
close to covering the horizon, but you should get four entirely
unique pictures of your DX environment with that antenna: REALLY N,
S, E, W. The Achilles heal of that Array is the fact that it, like
every other K9AY, demands a good ground for proper
operation. Frankly, I cannot imagine a finer antenna for domestic AM
DXing or 160 meter operation, if the antenna can be properly grounded.
Both my place on Orcas and here on the dunes at Grayland, achieving
even a poor ground is a real fight. Andy designed a system of four
radials for each of two loops for my use in the NW and they have been
very marginally successful, with no nulls being more than 40dB and
most being in the 30dB range. Nevertheless, the K9AY system with two
delta loops 15' high x 35' long (525 sq.ft.) is the antenna that kept
pace with a prototype of Dallas Lankford's QDFA four loop phased
array (non-reversible) two weeks ago here at Grayland. The K9AY was
clearly better (not by a huge amount) than the ALA100 array, even
though the K9AYs were very poorly grounded.
It happens that there is a way to use the K9AY loop heads to drive
EWEs or Super Loops or KAZs, none of which require grounding. That is
the second system that I am running here this weekend, first with 17'
x 60' Super Loops (better than the K9AY array but subject to
overloading by some of the stronger Japanese (yes!!!) In the morning,
I'll be A/Bing the K9AY Array with 17' x 30' Super Loops (1020 sq.ft
and better nulling.) I suspect that some version of the Super Array,
using the FLG100 loop heads, will turn out to be the antenna of
choice for most coastal settings. I'd love to compare it to a full
1500 foot Beverage, A/B. I suspect that they woulds be very
close. The down sides of the Super Loop is that it is not
switch-reversible and it requires four masts for a two-loop array,
where the K9AY only requires two masts.
To tell you the truth, I'm excited about these two new designs as
single loop antennas for DXers in restricted suburban settings. I
suspect that they will be almost as popular with the DXing community
as the ALA100 has been. The single loop K9AY of course requires
grounding, but is switch reversible... something that I have found
surprisingly handy. The FLG100, able to drive so many different
single loop configurations is probably my favorite of the bunch. It
does not require grounding.... but of course, it is not
switch-reversible, either. Ah, the Laws of Physics!!!
Anyway, you asked what I was testing out here and that is the
story. I hope that your back heals more quickly than you expect....
you are gonna love those FLG100 units.
John Bryant
Grayland, WA
Winradio G313e + two Wellbrook Phased Arrays
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