Thread: First Attempt
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Old March 21st 06, 09:21 PM posted to rec.radio.amateur.antenna
Old Ed
 
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Default First Attempt

Hi Michael,

Thank you for your comments! I'd be interested in trading experiences
with you on the OCF topic, either here or direct. Did you make one
or buy one?

I have interleaved some other responses below...

73, Ed

"Michael Coslo" wrote in message
...
Old Ed wrote:
Reg,

The type of antenna you describe is very useful and popular.

However, your assertion is much too sweeping as a generalization.
In no particular order, here are some caveats:
1. The qualifier "best" is largely meaningless, absent an agreed
set of weighted criteria for "goodness." (How important is:
size? weight? cost? visual profile? bandwidth? instant QSY?
gain? pattern? low-band performance vs. high-band performance?
power-handling capacity? need for tuner? etc., etc., etc.)


I'm always hesitant to use words like "best" for all the reasons you
state, but I think that Reg qualified things pretty well.


I think Reg's ONLY qualifiers were "all round, all band" (presumably
meaning 80 thru 10). To me, that description falls well short of the
mark, as "qualifiers."

Within the
qualifications of all band dipoles, the ladder-line fed general dipole
is pretty darn hard to beat. I recommend them to any new hams that ask
me for advice on antennas.

You can make a good case for this proposition. But I'm a bit puzzled
on how these qualify as A-1 newbie antennas.

First, our newbie to learn how to coddle finicky ladder line, bring it
into the shack, and make the transition to unbalanced feed. Then he/she
needs a crash course on transmatches:
1. Balanced or unbalanced design? (If unbalanced, may not work well
with this antenna; if balanced, may not work with future, coax-fed
antennas.)
2. Low or high power? (If low, may need to upgrade later.)
3. Manual or automatic? (If automatic, how interface to rig?)
4. Which brand and model? (Might Fine Junk or $quality$?)
5. New or used?
6. How do you operate the transmatch?

If our newbie wants some power-handling capability, and plans
to buy it new, he/she will need an extra 500 to 700 USD and more
space on the desk.

Re Reg's reference to a choke balun: I've been looking for good quality,
commercial choke baluns equipped with SO-239 inputs and outputs.
So far, I haven't found any; and I haven't been quite motivated enough
to make one. What should our newbie do to get one, if needed?

My rationale is that most new hams these days buy rigs that are
all-band, transistorized units.These units are also sensitive to
mismatches between antenna and rig. Most new hams are not antenna gurus
either. So here is an antenna that will allow them to get on the air
without a lot of fussing. The only real measurement caveats are some
lengths that you don't want to use.

I can't quite see how slogging thru all the above is going to be easier for
a newbie than buying a Buckmaster OCF or basic trap dipole, buying a
ready-made coax jumper of the required length, and then doing plug-
and-play with the (typical) rig's built-in auto-tuner. But it probably
would
be more educational.

So we end up with an antenna that allows the newbie to get on the air,
allows them to learn some stuff by twiddling knobs and such, then when
they have a bit more experience, they can tackle that more "advanced
antenna" with it's more exacting design, trimming , and measurements.

I'm having a hard time figuring out what antenna type(s) would be "more
advanced" than the random-length-doublet-with-outboard-ATU, and
yet require more fiddling.

But I will grant you this: IF someone decides from the get-go that they
want a glitzy transmatch at their operating position--whether they need
it or not--then the balanced-feeder doublet makes pretty good sense.
This would be especially true if there wasn't enough space for something
like a Buckmaster OCF, but there was enough space for (say) an 88'
doublet.


2. A good case can be made that choosing the "right" length is
"better" than a random length, within this type.
3. An excellent case can be made that center-fed is NOT always
the "best" option, within this type.
4. I'll let the fans of this antenna type chime in with why they
prefer balanced tuners and/or tuned feeders to the use of an
unbalanced tuner... if they want to. (I use more tailored

antennas,
and don't need a tuner of any kind, most of the time.)


As I do now. I've really been smitten with my OCF dipole, fed with
Coax, because in no small part, the feedpoint drops straight down to my
shack. That coupled with an automatic tuner in my radio , allowing me to
"plug and play.

But I still strongly urge newcomers to put up one of those ladder line
dipoles for the experience. They work okay, too! 8^)


"Reg Edwards" wrote in message
...
The best, all round, all band, antenna is a high centre-fed dipole of
no particular length, fed with an open-wire feedline of no particular
length or impedance, all the way to the shack, used with a choke-balun
and an unbalanced tuner.

It is good down to the frequency at which the dipole is about
1/3-wavelength long.

Simplicity = efficiency.

Once tried you will never return to anything else.
----
Reg.