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Old August 7th 04, 03:45 PM
Brian Kelly
 
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Default Multiband HF Antenna Nipping | Bottom Up or Top Down?

I'm mulling the construction of a "nested HF squalos" antenna. At
least three bands, wires for 20, 15 and 10M in a coplanar arrangement
on four fiberglass spreaders. Basically a multiband cubical quad
driven element with a common feedpoint, single feedline and flopped
over into the horizontal position. After wading thru all the modeling
comes the real world. I'll cut the wires a bit longer than modeling
indicates and start manually tuning the thing to resonance by nipping
all the wires a bit at a time using the 259B, etc. Each nip will
affect the resonant points of all the wires due to the interactions
amongst the wires. The question: Which wire should I start tuning
first? I've seen posts which state that one should start nipping from
the lowest band to the highest band and I've seen recommendations to
start with the highest band and work down to the lowest band.

Which way is it??

Tnx, w3rv
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Old August 10th 04, 02:12 PM
Brian Kelly
 
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Default

Cecil Moore wrote in message ...
Richard Clark wrote:
Common advice I've seen is work with the most wire first.


Common advice using common sense. An 80m dipole can be close
to resonance on 10m (big effect) but a 10m dipole is completely
non-resonant on 80m (virtually no effect). And a 5% adjustment
to an 80m length equates to a 40% adjustment to a 10m length.


Been there, just did it to a Field Day G5RV . . Uggg . . "Tack some
wire back on it."

In mathematical terms, tuning the shortest wavelength antenna
first is a *diverging* infinite series, good for sun tans
but bad for ham operating time.


Richard:Cecil: Makes sense, bottoms up!

Tnx.

w3rv
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