On Fri, 07 Sep 2001 <email@example.com> 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
> 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
> each of the loop ends to themselves and/or coax? I'm using the
> configuration that provides for a vertical spreader as an anchor
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 ?)
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today! For your FREE software, visit:
List Sponsored by AN Wireless: AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 96 feet for under $1500!! http://www.anwireless.com
FAQ on WWW: http://www.contesting.com/FAQ/towertalk
Administrative requests: towertalk-REQUEST@contesting.com