Richard Clark wrote in message . ..
On 20 Apr 2004 09:06:35 -0700, (N2EY) wrote:
These apologies ring false. The issue of gaps is desperate and the
selection of tubular has no basis in special characteristics. All
such considerations MUST yield to simple scaling. For instance, if
you need 0.8 and have 0.9, there is no magic formula beyond
proportions necessary to achieve "what should be."
I disagree! In the QST article, Lattin describes an 80/40 dipole using
his method. It has wires dangling from the stub junctions to get 40
meter resonance.
Hi Jim,
OK, you disagree, but with what?
With the idea that scaling answers all questions.
Scaling will ALWAYS answer
everything but the mystical apologies.
The two-band 80/40 dipole in the QST article has extra wires at the
junctions of the 80 and 40 sections because (according to the author)
the velocity factor of the tubular Twin Lead makes it necessary. Those
wires might or might not be required with a unity velocity factor.
Most important to me is that the antenna offers no real advantages
over, say, a conventional trap dipole. Yet it offers many
disadvantages, such as mechanical frailty and difficulty of
duplication.
This is more pilot error than design error (which has its own
problems, of course).
In a perfect world, maybe. But in the real world of ham radio, most
hams have limited materials, test equipment, time and space. An
antenna made out of unobtainable materials, which requires
unobtainable tools and test equipment to build and adjust is only of
academic interest to a ham.
And again - what advantages does it have over, say, a W3DZZ trap
dipole?
I see no such issues if the theory were hammered out. It is plainly
these readings of tea leaves that frustrate construction, because when
a design is described, it is most clear and concise - it just doesn't
work is all.
Exactly! If it cannot be easily duplicated by a ham with typical
resources, what good is it?
Like I said, I've done some measures and added a dozen more since.
The results are interesting. I can come up with a four band antenna
without too much trouble; however, getting those bands into Ham
regions (all of them) is another matter. I can do this with a simple
run of twin lead, and one strategically placed short between them.
Which is not what Lattin did at all. Your design sounds far superior.
Is it on the web anywhere?
This antenna (usefully resonant or otherwise) is no worse than any
wire strung between poles - just two wires instead of one, hardly what
I would call fragile. If it has an advantage over your W3DZZ trap
dipole, I leave that strictly in the eye of the beholder as I have
full faith it won't be any worse.
All depends on the wires. I use recycled #12 house wire, which stands
up under ice loading and high winds here in EPA. Yet it is hardly
noticed by the neighbors.
Any way, such work offers a step towards an antenna with MORE gain
(and more wire, a third one) by constructing a Franklin Array style of
antenna. True, not a multi bander, but I am not particularly nailed
to the floor over that.
The main attraction of the Lattin is its claim to multiband operation.
Otherwise one might as well go with a plain dipole.
73 de Jim, N2EY