[amsat-bb] Re: Arrow vs M-Squared Antenna Question
kd1pe.1 at gmail.com
Wed Apr 22 14:16:19 PDT 2009
Dave, if you want a more Technical answer, you may feel free to contact me
off the BBS (Direct) and I will get as technical as you like. The simple
version is that at its center, an antenna element is at a null point and it
may (by design) be either free floating (not grounded) or grounded to the
mast. Truthfully it boils down to who designed the antenna and what the
designers preference was... Operationally there is little if any difference
from this standpoint. Constructionally it is easier to make a grounded
element yagi and of course by design they should also (unless it is a really
crappy design and there are some out there) be stronger (more robust) than
the insulated antennas...
Bottom line, don't worry about gain, most advertized figures lie anyway in
that they give a figure devised for their own (not yours the operators)
ends... If the antenna does what you want, then it is a good one, if it
doesn't it is no good for you... Remember the higher the gain the smaller
the radiation pattern and the harder it is to hit a target (think shotgun
Vs. Rifle) The shot gun has less directional gain, and will not shoot as
far, but it is easier to hit a close in target (LEO's) than is the higher
gain (Rifle) antenna...
For all intents and purposes a 3-4 element yagi is all you need on 2 meters
and 4-5 on 435 Mc.
Subject: [amsat-bb] Arrow vs M-Squared Antenna Question
>I just received an Arrow and I already had an M-Squared 2m antenna. The
> M-Squared has the elements isolated from the boom by means of rubber
> grommets; the Arrow has the elements attached to the boom and they are not
> isolated. It seems to me that makes the elements, boom, mast and coax
> conductor all grounded. Right?
> Doesn't that make the Arrow less effective in radiating and in reception?
> Dave // DM78qd // KA0SWT
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