[TowerTalk] Quad Element Tuning

[n4kg@juno.com]

On Fri, 07 Sep 2001  <d@peak.org> writes:
> 
> Hi All,
> 
> I currently am completing construction of my first quad beam 
> antenna.  I am looking for suggestions about how best to tune 

> 
> Q1)  What is a good method to tune each of the five reflectors?  I 
> can  target a fixed frequency off-set from each of drivers (by 
> percentage). > If so, what should the off-set be?? 

	W8JI reports that self resonant elements tuned to the
	LOWEST frequency used make good Quad reflectors.
	You could start with the formula length (1050?/F) and
	tune the reflectors for zero reactance at the bottom of
	each band.  Tune the reflectors FIRST without the DE
	in place.

> I'm not sure how to use the  MFJ259B
> to tune the F/B or Gain(max), if it can at all.  I could use a field
> strength meter but that's subject to error and my neighbors.

	Antenna Analyzers measure impedance and SWR.
	You need a remote transmitter or receiver to measure
	F/B.  Gain is VERY hard to measure accurately.
	Fortunately, Gain bandwidth is quite broad compared
	with F/B so once you achieve your desired F/B, the gain
	should be within 1 dB of max.  Gain and F/B typically do
	NOT peak at the same frequency.    N4KG
> 
> Q2)  Is there a suggested order through the bands to be tuning 
> either  the dir. or ref.? i.e.- 10>20 or 20>10?

	Higher frequency elements are nearly invisible to lower
	frequency elements.  Lower frequency elements are more
	likely to affect the tuning of the higher frequency elements
	so I would start with 20M and work up in freq.   N4KG
> 
> Q3)  And finally, any suggestions about what is a good method to 
> secure
> each of the loop ends to themselves and/or coax?  I'm using the 
> diamond
> configuration that provides for a vertical spreader as an anchor 
> point.

	One of the more interesting mounting schemes I have seen
	uses hose clamps over a rubber? loop with a piece of small
	rubber hose at each corner for the wire to run through.  The
	rubber pieces came from an auto parts store.  I forgot what
	kind of lines were used.   Tom  N4KG

> Thanks for input!
> 
> Paul   (What is your callsign ?)
> 

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