In a message dated 5/2/01 4:42:55 PM Pacific Daylight Time, K3BU@aol.com
writes:
In a message dated 5/2/01 12:30:20 PM Eastern Daylight Time,
w8ji@contesting.com writes >
> I'd bet almost zero quad wires fail from exceeding tension limits of
> the wires, and most fail from flexing at joints.
>
I will take the bet!
I never had wire fail in Quad from flexing. There is (almost) no flexing
when
antenna is properly strung, with just enough tension to keep the wires from
flopping or flexing. In the corners I use black plastic ties, wrap it
around
the wire couple of times and thread it through the hose clamp, which clamps
to the spreader. I keep about half inch distance between wire and hose
clamp
to prevent any potential arcing over at high voltage point (due to
capacitance). When the spreaders and wire are up, I keep pulling one corner
to get the proper tension, just enough not to bend the spreaders and make
wire nice and tight.
I wouldn't use aluminum wire, copper is cheap and good.
Wire I use is #12 or #10 house PVC coated solid Cu wire. I pre-stretch it
(harden) and it doesn't go anywhere after that. Originally I though that
insulated wire would minimize the rain static, but the difference is hardly
noticeable. Insulation only prevents corrosion and wire has to be shortened
by about 4% due to lengthening by insulation.
Properly designed and installed quad will provide trouble free service and
run circles around Yagis (up to 4 elements). You can have quieter reception
and dual polarization with one feed line.
That ain't no folklore, it is a proven, measured fact (not just calculated).
.
Yuri, K3BU
>>
There are no flexing joints or arms in a quad when the wires are properly
strung--in particular the 2 element 5 banders. For example in the LB the
wires pull the arms slightly to one side. With their wire mounts there is no
flexing. I've seen wire mounts to the arms that had a lot of flexing and
they failed-not the wire. On a good wire to arm mount, no shrink on tubing
is needed. With tapered quad arms the back rope holds the arms in one
position. One find this out when they actually have used a quad through
observation--not an opinion. For those who are full of opinions on antennas
they have never used I'd like to ask "Don't you ever get tired of being
wrong? Opinions are of value but first hand experience is better.
I had a 5 band LB quad up with the .06" aluminum welding wire. We had some
ice loading at night and wind I didn't see. Some of the wires stretched a
little. Copper clad steel has been bad mouthed for quads. It has worked
just fine for me in every application I've used it in--including quads. I
have a mile of it and use it wherever I can.
The DE's are all tied together on the LB and another make. I got the same
patterns (?) on the air as I did in Eznec. I didn't really need a rotator as
answers to CQDX's came from all directions. Even with a fast rotator it was
very difficult to center on the direction where a DX station was. On 10M the
free space pattern is tilted down about 35 degrees due to the unbalanced
currents in the other DE's except the 20M DE. Individually fed DE's with a
remote coax switch like Antenna Mart has is the only way to go for the best
patterns all on the horizon.
There was a W6 who had an article in QST of his 5 band quad with all elements
spaced 12' with individually fed DE's and he actually tuned the reflectors
from the roof and ended up with fair performance.
The "Ultimate 5 or 6 band 2 element Quad" will be with tapered spacing of
about .15 WL, W2DT Handelsmans slightly rectangular orientation for increased
gain and Cebiks 2 wire design that also increases gain that was shown in
AntenneX Internet Mag, copper wire that enables all joints to be soldered and
never any joint deterioration, a variable Xc in each reflector all ganged
together to a selsyn on the mast to enable it to be quickly tuned for max
gain or F/B and each DE individually fed with 100 ohms balanced coax to a
Johnson Match Box that insures max power into the input of the feedline on
any frequency and tuning. K7GCO
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