Oh yes. I had to lengthen tips on the refl and of course all the element
lengths were different due to tubing size.. The ant has been up since
last Oct. Tnx for thinking of me about it!
204: Yes it can but IIRC the ref has to be lengthened. Also IIRC none of
the element dims are per the HyGain book when its made into an OWA. It
all comes out differently in the design prog. I've never had one of
these at my stations. N6ND has done significant design work on OWA'ing
the 204.
73 Art
On 2011-08-20 06:13, TexasRF@aol.com wrote:
> Art, re: 204BA: wonder if they can be reconfigured as a 4-el OWA
> design? Love that bandwidth!
> On the 3-el 40 tip size: keep in mind that as the taper continues, the
> element length has to increased due to the taper effect. The yagi
> design programs will show this.
> 73,
> Gerald K5GW
> In a message dated 8/19/2011 8:47:48 A.M. Central Standard Time,
> k6xt@arrl.net writes:
>
> Pete
> Someone else replied about K4JA's loss saying it was a hurricane. Our
> winds don't get up there or haven't yet.
>
> An elephant gun to Asia would be good. I'm trying to avoid a mast and
> associated hardware in the tower. Another piece of R45 above the top
> guys, at 75 lb, seems as light as anything else I could put up there.
>
> The small 20 above the 40 gives me the opportunity for 3 phased 20's.
> Someone suggested a 204BA, I have some of those elements but would
> probably make it a 3L.
>
> My 3L40 is an old DXE. From the factory it came with (what I
> consider)
> huge tips. Starts out at 2 inch, ends in telescoping tubing at
> 0.875in.
> To me that is gross overkill at the tips. I replaced the outer 16
> feet
> with 204BA elements to cut the weight but more important the wind
> load.
> My neighbor K0YW has a duplicate of this ant. His element sag is
> something like 3X mine. This ant is up on a hilltop 70 ft crankup
> cranked down to about 50 ft for the past year with no probs so far.
>
> Gotta wonder if K4JA's pair of 40's started twisting in opposite
> directions. AB105 is stout stuff, I had some up 30 yrs ago in San
> Diego
> area.
>
> 73 Art K6XT
> Allison, Colorado
> "One of the harshest lessons learned from recent disasters,
> especially Katrina, is that you are your own first responder."
> ...LtGen Russel Honore USA
> GMCC CWOps 728
> NAQCC 1342 SDDXC
> ARRL TA
>
>
>
>
> On 2011-08-19 05:54, Pete Smith wrote:
> > You're right to be concerned about twisting loads. K4JA, who is a
> > pretty good back-yard engineer, lost a 200-foot AB-105 rotating
> tower
> > with 2 40m OWAs on it in a windstorm, and from the debris it was
> > obvious that it had twisted to failure. Afterward, he told me
> he sure
> > wished he had a shear pin or other provision for breaking the
> > connection between his rotator and the tower, because if it had
> been
> > free to move it might well have survived.
> >
> > By the way, if you plan to phase the two 3L 20m yagis, wouldn't
> you be
> > better off putting the top one at 100 feet? Or are you looking
> for an
> > elephant gun to Asia?
> >
> > 73, Pete N4ZR
> >
> > The World Contest Station Database, updated daily at
> > www.conteststations.com
> > The Reverse Beacon Network at http://reversebeacon.net, blog at
> > reversebeacon.blogspot.com,
> > spots at telnet.reversebeacon.net, port 7000
> >
> >
> >
> > On 8/18/2011 8:51 PM, Art K6XT wrote:
> >> I've started construction of a 150 ft Rohn 45 rotating tower
> using K0XG
> >> base and four rings, top ring at 140 ft. Just above the top
> ring will be
> >> a 3L40 and possibly a small 20 above that, like 3L.
> >>
> >> I'd be very interested in any experience or anecdotes on
> projects like
> >> this using R45. That tower was selected because I already own
> it. My
> >> area has the potential for icing. The ice I've seen is very light,
> >> nothing like back east or in EU. But I suppose its possible.
> Not too
> >> windy, the strongest seem to peak out around 70mph and that's rare.
> >>
> >> One issue I see is, there are no torque bars on the tower. All its
> >> torque is transmitted to the rotator on the ground. K0XG's
> rings do have
> >> torque bars but that doesn't help the tower.
> >>
> >> The general plot is to add antennas down the tower above the
> guy rings.
> >> Second 3L20, a shorty 40 Hygain, 10 and 15M.
> >>
> >> Replies to k6xt at arrl dot net are FB, or here.
> >>
> >
> _______________________________________________
>
>
>
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