[TowerTalk] Quad vs SteppIR

[N2TK]

Hi Tom,

When I had a quad and monobanders, the quad was always quieter from snow
static than the monobanders. Was wondering if the SteppIR would be quieter
than a regualr aluminum beam during a snow storm since the snow would be in
contact with fiberglass instead of aluminum? Or would the static charge be
the same regardless of material?
Tnx
N2TK, Tony 

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Tom Rauch
Sent: Monday, August 30, 2004 10:54 AM
To: towertalk at contesting.com; Bill Ogden
Subject: Re: [TowerTalk] Quad vs SteppIR

> I am wondering if a 3 element SteppIR would provide any
noticable
> improvements in my situation.  The SteppIR is probably
easier to handle and
> the 180 degree switch appears to be a very nice feature,
but is this
> sufficient to justify switching?  Does anyone have
experiences about quad
> vs SteppIR?

Hi Bill,

This is all based on "how it works" data, not an actual comparison. I've had
quads and Yagis, and the SteppIR is nothing but a Yagi.

If both your old quad and the proposed SteppIR antennas both have reasonable
efficiency, you can expect performance to be roughly proportional to boom
length, assuming the number of elements is nearly optimum for any given boom
length. This means the SteppIR should at least equal if not actually improve
performance as long as it has a longer boom. My bet is that it would
actually improve your system a few dB for both receiving and transmitting.

I almost hate to say this, but an occasional reminder is due from time to
time. A quad has no real gain advantage over a similar size Yagi. The
original "2dB" thing came from flawed measurements of a scaled model by a W2
and W6 long ago, and once it was in print that was it...it took on a life of
its own. At some heights a small quad antenna can show a little advantage
(perhaps 1 dB) and at other heights a slight loss over a similar boom length
yagi. Overall they are about equal, although for some reason long quads did
not fair well in actual measurements (Wayne Overbeck N6NB and Dave Bell
W6AQ, CQ Magazine, May 1982).

Another quad myth is capture area, but physical aperture is not the same as
electrical aperture or "capture area".
Capture area only relates to gain and frequency, so any antenna with the
same gain on the same frequency has the same capture area! That's true if
one is a big box, and the other is a small single plane element. Capture
area also does not determine S/N ratio, so it a moot point anyway.

Directivity sets receiving, not gain or capture area (more correctly called
effective aperture). I would expect the SteppIR to receive better, because
it should have better directivity. The exception might be in times of
inclement weather, since the quad generally has less of a corona
(P-static) problem. In the few quads I've had here, that was the only
advantage I ever saw when comparing them to similar size Yagi's.

73 Tom


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