On Fri, 4 Jan 2008 17:08:10 -0500, "James" <jnipperxxx@[EMAIL PROTECTED]
>
wrote:
>1. What is the "best" 2 meter antenna type for me (I don't need a dual
>bander. I will only use 2 meters).
Hi Jim,
If that is asking for a manufacturer recommendation, I will leave that
to others.
>I know that a 5/8 whip will have
>the best gain, but I have seen some comments that a 1/4 wave may work
better
>in the mountains, because of the angles involved.
Either works fine. Mountains are immaterial unless you are trying to
work off the pointy end of the vertical (even then, there is no
difference they both provide nulls). There is certainly a lower
directivity with higher angles, but higher angles also suggest closer
proximity. Any proximity that allows you to "see" the source would
also allow you to talk to the source. You don't need any
extraordinary amount of gain/power to accomplish that when a handheld
can talk to the space shuttle.
>Yet, I know that a 1/4
>wave needs a good ground plane, which a softop probably will not do very
>well.
So would a 5/8ths. You may be tempted with halfwaves (no ground plane
required). Take care, they can be wildly mistuned by nearby metal
and/or coax length, or any number of other considerations. This
follows the rule: no such thing as a free lunch.
> It would seem that with a 1/4 wave, I would want the base of the
>antenna at or near the top of the Jeep. I am also aware of a colinear
>antenna, but that would be quite tall for me !!
So stick with a single element. Gain is not all that it is cracked up
to be. Your intended mounting position will work just fine.
>2. Is it best to have the antenna element fully above the top of the top
of
>the Jeep ?
If it were a hard top, then mounted dead center would be best. You
aren't likely to notice any difference anyway (and you don't have a
hard top).
>3. If I use a spring to offer some protection for the whip, doesn't the
>spring add to the length of the antenna, and I would have to tune the
whip
>for resonance ?
Ya sure, you betcha. Buy a whip that is springy in its own right
(maybe using piano wire - this suggestion will probably attract flack,
just make it thicker wire).
>4. What is the best (maybe strongest?) mount type ? I am accustomed
to
>the 3/8" - 24 type stud mount. It seems strong to me. What are
the
>advantages of the NMO and other mount types for my purpose ?
All very fine. You can get by with less, but what is im****tant is a
tight weather seal.
>5. After choosing the antenna type ( 1/4 wave, 5/8 wave / etc) what
is
>the best antenna ? Larsen, Diamond. Other ?
All of the above.
73's
Richard Clark, KB7QHC
|
