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[TowerTalk] Since my name was mentioned...

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Subject: [TowerTalk] Since my name was mentioned...
From: (Tom Hammond - N0SS)
Date: Mon, 21 Jun 1999 10:29:23 -0500
Greetings to all:

Well... since Eric (KI0MI) brought me and my new Bencher SkyHawk
into his discussion of the Force 12 C4 (which was just installed
at the Univ. of MO (Rolla, W0EEE) club station), I guess now would
be a good time to report my first impressions of the SkyHawk.

Sorry guys!  This report is pretty long, but that's how I talk
AND write... get used to it, or press <Delete> now!

For the past 20 or so (maybe 25) years, I've had a Ky-Gain TH-6DXX
up at N0SS.  The antenna has given me NOTHING but excellent service!
But, as with all things, you gotta trade up sometime... remember,
he who dies with the most toys wins!  I looked at the specs for a
number of the newer antennas and for various reasons, decided upon
one of the new(er) offerings, the Bencher SkyHawk 3X10 no-trap
10-el Tribanders, even though I'd seen NO published advertising.
I visited Bencher's web site and ordered their mail brochure on
the antenna.  From what I received in the mail, and what I saw on
the web site, I decided that the SkyHawk was what I'd go with.

I send e-mail requests for price quote to about 15 different
vendors.  About eight replied.  Several replied that they didn't
offer Bencher antenna products and the others quoted a price on
the order of $780 + SHIPPING.  Well, all except one... THAT vendor
offered the antenna for $699 + modest shipping!!!  Guess which
vendor I went with???

The antenna having arrived, I set to the task of assembly... out
in the front hallway of the house... thank God for a VERY supportive
XYL (Jeri, K0RPH, my old callsign).

I first assembled all of the elements.  I assembled them each in
two pieces, as close to equal lengths as possible.  I say this
because there's a single center tube which must fit on one or the
other 'half' and which then makes then no longer 'equal' in

Each element comes MARKED and 'bagged' in its own plastic baggie.
All pieces of each side of the element were telescoped within each
other so there's NO GUESSING, and so you'd have to work REALLY hard
to get the parts swapped or mis-matched.  A really SMART (and much
appreciated) step by Bencher.  During assembly, I noted that Bencher
gives you a VERY AMPLE amount of inner tubing overlap (often more
than 8"-10", if I recall) to ensure that every piece of element is
well-supported within the preceding element. All holes were drilled
and everything was 'gooped' (by the user) with an ample supply of
Bencher's own "Butter-It's-Not" (copper-colored)anti-seize/anti-oxidant
compound... Bencher provides two (2) packets of this compound, I used
less than one, and still "laid it on" amply.

Though not specifically measured, the wall thickness of the elements
appears to be heavier than that of my old TH-6DXX... nice.  All
elements 'nested' nicely.. not tightly, but it was certainly obvious
that they were designed to fit one inside the other... no binding
AT ALL... all burrs removed prior to receipt.

ALL(!) elements of the SkyHawk are INSULATED from the boom by what
appear to be POLYETHLENE insulators.  These insulators are swage-
fitted onto the elements and generally do not require further
adjusting, but it's wise to measure their centers from each end
of the element piece on which they are mounted. I did have to slide
one insulator a small bit.  It was a trick to do, they're pretty
tightly fit.

Once the elements were assembled and set aside, I turned to the job
of assembling the boom.

The boom of the SkyHawk is 2" O.D. and (with the exception of the
outer 36" on each end of the boom) is double-walled.  In fact, it's
TRIPLE-walled in the CENTER-MOST section of the boom.  This reinforcing
created a REALLY STRONG boom... much stronger than on my TH-6DXX, and
one which requires NO catenary support wires.

One of my boom sections had become dented (creased slightly) during
shipment and I could not insert the inner tubing into it.  I called
the Bencher factory late Friday morning and asked them to send a
replacement section.  They agreed.  To my sheer amazement, the new
boom section was DELIVERED to my doorstep the NEXT morning (Saturday),
less that 24 hours after I'd reported the problem.  I consider THAT

The boom went together well... everything lined up and all STAINLESS
bolts went in as planned, and with a light coating of Butter-It's-Not
on the threads, to help ensure against galling of the stainless once
the nuts are tightened snuggly.

The one (small) problem I did have with boom assembly was merely
with properly identifying the section designation and direction of
each boom piece.  The manual shown a pictorial of each piece, but
even with this, it still took a bit of effort to not pick the wrong
boom piece at the wrong time.  I'd like to see Bencher take a big
marker pen (or stamp) and label each boom section individually.
That's make assembly a lot quicker... and more idiot-proof... some-
thing I can REALLY appreciate.

Because the SkyHawk is designed with six elements on one side of the
mast and four elements on the other side, the antenna wants to be a
bit 'off-balance'.  Bencher includes WEIGHT and WIND LOADING
compensators for just this problem.  The compensators are in the
form a gray PVC (I think, may be some other compound) tube (for
WEIGHT compensation) and a small rectangle of the same gray plastic
(for the WIND LOADING compensation).  These items have their own
mounting hardware and they go on with no problems.  Once installed,
the beam is very evenly balanced.  I foresee no problems from this
part of the design.

Bencher (thoughtfully) provides MORE than ample hardware for the
builder.  Enough that I was able to lose a couple screws/nuts/pop-
rivets into the grass outside and still not have to make a flying
trip to the hardware store for replacements.  This small item was
really appreciated... thanks guys.

Attaching the elements to the boom was performed outside... OF
COURSE YOU DUMMY... Jeri had already reminded me that I couldn't
fully assemble the thing inside and then get it out the doors.
But before I took things outside for assembly, I loosely installed
all of the element-to-boom clamps and saddles to the boom so that
if I dropped a nut or bolt, it'd fall onto the floor, rather than
to the grass and be lost forever.  This turned out to be a wise
move as I later proved with the few nuts and bolts I didn't install
inside.  The element-to boom clamps and saddles are made of heavy
stamped aluminum and of cast aluminum in some cases.  They are very
heavy-duty and appear to be significantly stronger than those on
other antennas recently built and installed.

Outside, the antenna was assembled (elements to boom) in two more
or less equal halves.  I did this because we still had to carry the
antenna out to the tower site through trees which would not permit
the fully-assembled antenna to pass.  I also performed this part of
the assembly at a location where there grass which had been cut,
rather than further out in the woods, were it (weeds instead of
grass) had not been cut.  No problems here except for the fact that,
on my haste to complete the assembly, I'd failed to 'goop' several
of the element ends which were inserted into their other halves and
pop-riveted together.  Out came the drill and these pop-rivets were
drilled out, the element ends 'gooped', reinserted and again pop-
riveted back together.  Again thanks, Bencher, for the extra pop-

Finally out at the tower, the two halves of the antenna were set
onto saw horses, slid together (but not bolted) and final
measurements taken to ensure that things had gone together properly.
Too easy...!  I soon found that (due to operator error) I'd managed
to install the elements on one half of the boom backwards.

Off came four elements, they were reinstalled in the proper order
on that half of the boom and the two boom halves were again mated
together to be bolted in place.  Wrong!  It turned out that the
elements for that one half of the antenna were originally CORRECTLY
installed(!) and that I'd attempted to mate the two halves of the
boom together with one half rotated 180 degrees out of phase.
20 minutes later the elements were again properly installed and the
boom section rotated thru 180 degrees (horizontally) and BOLTED
together.  The antenna was (finally) ready to be installed.

Installation went without major hitch.  Bencher provides a two
boom-to-mast plates: one for mounting on the mast, and the other
to be mounted on the boom.  Then the antenna is lifted and the
bolts (partially) installed onto the antenna-mounted plate are to
mate with key-way holes and slots on the mast-mounted plate.  Once
mated, the antenna is allowed to drop into position and the other
bolts are easily inserted and tightened. The only problem I had
with this "theoretical" methodology was that the bolts provided to
be installed in the boom-mounted plate included an integral 'washer'
which was only very slightly smaller than the holes in to keyway
of the mast-mounted plate, and it was a real bitch getting the
antenna at 'just' the proper attitude to allow these 'washered'
boltheads to fit cleanly thru the holes of the keywayed sots.
Once done though the antenna settled precisely intowhere it was
supposed to seat and the rest of the installation was flawless.
(I've since spoken with Bencher about the boom-to-mast mating
problem and they advised that I received one of their 'original'
versions of the plate, which has not been re-engineered to provide
more than ample clearance for the boom-attached bolts).

Once installed, we (all) ran into the shack to check the SWR.

I was SHOCKED to find that SWR (particularly on 10M) to be pretty
outrageous!  Well over 3:1 on 10M and higher than anticipated on
20 and 15 as well.  I was devastated!

Some e-mails to K3LR suggested that something HAD to be "out of
whack" (a technical term to be remembered by you newbies).

The next weekend we took the MFJ Antenna Analyzer out TO the tower
and hooked it up to the short length of coax from the yagi (sure
is GREAT having a crank-up tower!!!).  The SWR was 1.1:1 at the
bottom of 20M, rising to about 1.5:1 at the top.  Similar readings
were found on ALL BANDS!!!  This indicated "bad coax".  But this
could not have been the case because I was using 3-year old 9913F
(or equiv.).  So we confidently attached the dummyload to the
tower end of the feedline and chugged (some run, I 'chug', esp.
after 2-3 trips) back into the shack to check the SWR on this new
coax.  Surprise!  SWR was all over the place on 10M and to a lesser
degree on 20M and 15M.  Then it hit me.  The feedline I was REALLY
using was not the 'good stuff', but I combination of RG-8, 75-ohm
TV hardline, and more RG-8.  The 'good stuff' went on the new(er)
80/40 dipole.

Replaced the bad coax with new and the SWR came in right where it
was supposed to be...!!  No complaints now.

I've not taken nearly enough time to fully evaluate the SkyHawk
against the old TH-6DXX, but what I've seen so far, I like.  It
appears to have more forward gain and possibly a slightly more
narrow beamwidth, but that's not a certainty yet.

The only thing I've noticed that I'm not totally pleased with is the
fact that when the wind blows, the SWR seems to vary a bit.  Enough
sometimes that in periods of sustained winds, my automatic transmatch
wants to re-tune.  I've spoken with Bencher about this problem and
they are offering (or will soon offer) an optional driven element
spacer which will hold the three driven elements (two of which are
parasitically excited) in close (but steady) proximity to each other,
so that the SWR doesn't bounce around during windy times.

Regarding the assembly manual:

The manual is well-written.  Each step is clearly set out.  Sometimes
almost TOO clearly set out in fact.  I say this because the very same
text is written for each of the ten (10) elements, with only the
part name changed.  The size of the manual could have been reduced
by several pages (at least) if the base instruction would have been
printed ONCE and then each step referenced back to that specific
instruction with a check-off box for each element.  Check-off boxes
are available now for each individual step for each individual element.
I'm sure that Bencher wrote the manual as they did with the intention
of making it idiot-proof.  As a result, I think too much use was made
of the new "cut 'n paste" options available in word processors

I already mentioned that I'd like to see the boom pieces batter
marked.  I'd like to have them better identified (verbally) in
the manual as well.  This might help eliminate having to mark
each individual boom piece.

In the manual there is reference to NOT over-tightening the stainless
nuts and bolts in order to eliminate galling of the metal.  The manual
(at least the manual that I have, may have been changed by this time)
suggests using a torque wrench to tighten the nuts but then fails to
provide any info regarding the amount of torque to be applied.  It
(the manual) also suggests an alternate method of tightening the nuts:
"... tighten the nut until the lockwasher is flat and the tighten it
no more than one quarter additional turn."  This methods works fine for
those instances where you're tightening nuts on a bolt that secures two
thickness' of FLAT metal where there's virtually no compression", but
it will not work (I believe) for instances where you're securing a
bolt THROUGH a piece of tubing which can compress significantly more
than that which can be tightened by a 1/4-turn of the nut.  In this
case (which was not addressed in my manual) it appears that one (1)
complete turn of the nut is required, rather than a quarter turn.

Would I recommend the SkyHawk to others?  Emphatically YES.

Was it easy to assembly? Yes.  Quite a bit easier than my TH-DXX
  which I still consider to be an excellent antenna.

Does it 'play' well?  Seems to, but this is based upon only limited
time to operate.  But from what I've seem, I'm gonna be plenty

Is the antenna mechanically well-made?  Absolutely!  No question
  there!  Easily as well-made as the Mosley TA-series, which appears
  to have been the 'standard of comparison' for years.  And MUCH(!)
  better made than many of the current offerings.

If to you have any questions I might be able to answer, don't hesitate
to drop me a note.

If I have made any mis-statements, I welcome those constructive 
corrections.  However I DO NOT wish to become embroiled in a
discussion of the relative merits of ANY antenna of the next.
The foregoing was a statement of my initial impressions about the
Bencher SkyHawk,  If you don't like 'em, dump 'em!

73 - Tom Hammond   N0SS

Disclaimer - I have NO AFFILIATION with ANYONE... especially Bencher
or any of its distributors.  I'm retired and owe allegiance to no one..

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