[TowerTalk] 6 mtr quad
Joe Giacobello, K2XX
k2xx at swva.net
Wed Aug 31 13:44:25 EDT 2016
Ed, I have been using quads since the late 70s. My first one was a
Skylane tri-bander, which used low strength, flimsy spreaders compared
to what's available today. I've also had a couple of six band quads
with four elements on 10-20M and seven on 6M with a 24 foot boom. They
do indeed work well and, when multibanded, are far less of a compromise
than multiband Yagis. A 2 element quad has only about 0.3 dB less gain
than a three element monoband Yagi. Going to multielement quads beyond
three elements is an exercise in rapidly diminishing returns. The gain
increase is relatively small given the increase in expense, complexity
and vulnerability. Four element Yagis and beyond are then a better
investment.
I am currently using a two element duobander on 30 and 40M on a 20 foot
boom. It's almost equivalent to a three element monoband Yagi but on a
far shorter boom. Cubex's 26 foot spreaders have held up well at this
windy QTH, although the combination of ice and wind can be destructive.
73, Joe
K2XX
> Ed Sawyer <mailto:sawyered at earthlink.net>
> Wednesday, August 31, 2016 9:16 AM
> The Quad vs Yagi debate is timeless. I always thought there were a number
> of things contributing to it:
>
> - Back in the day before computer optimized gain yagis, the quad
> was a simpler way to get more gain on a given boom. The full loop started
> it off with something like 1.3dB gain over the dipole element and placing
> evenly spaced elements gave good results for a 2 or 3 el quad.
>
> - The average height of a quad (I have to believe) is the center
> point between the top wire and the bottom wire (or diamond tips) so
> the HFTA
> analysis should be the same for a yagi vs a quad at a given height when
> horizontal polarization is used.
>
> - However for the early years, low "towers" of 30 ft or so, if they
> were fed for vertical polarization and happen to be in a good to excellent
> ground conductivity area, the take off angle was likely better for long
> "band opening" DX and impressed their owners.
>
>
>
> Today, there is much better ability to get maximum gain out of a
> longer boom
> yagi that is way easier to install and maintain and we understand the take
> off angles much better.
>
>
>
> I could be wrong on the above folklore, but that's my guess.
>
>
>
> Ed N1UR
>
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