Well. Shoot, John. It really kinda depends, on your goals, your
financial resources, and available real estate, target bands and
target contact locations, and MORE... but my research tells me
THE ANTENNA WITH GAIN IS PRESUMPTIVELY THE BETTER
CHOICE, ... usually, in most cases, on most days, but IT CAN
DEPEND on many factors.
[Note - we are comparing the vertical to the yagi - and not other
types of antennas...]
First, the Yagi generally has some measurable gain. The typical
vertical radiates equally in all directions. These can both be a
good thing and a band thing depending on what you want to
accomplish. If you are seeking rare DX on the higher bands
(say 40 and higher) then a yagi with gain (i.e. serious directionality)
might be of great service. It helps focus the energy of your
transmission on the target DX location, and helps to focus on
the receive signal, with nulling (attenuation) off the sides and back,
so your target signal generally has better signal-to-noise. Done right,
the yagi can have good take off angles for long DX or for a more
domestic signal - depending on how it is done.
A vertical is a good all purpose antenna in that it is omni directional,
but IT WILL NOT HAVE ANY SIGNIFICANT GAIN IN ANY DIRECTION
(putting aside multiple element arrays for the moment.) The vertical
tends to have better DX take off angels ON LOW BANDS (i.e. lower
angles of radiation on the lower bands, like 16, 80, 40, and somewhat
on 20 but it gets worse as you go to higher bands.....) so on
higher bands it tends to have a much higher angle and transmits more
skyward - making it a more of a domestic and less of a DX antenna as
you work the upper bands. This might be good for those more local
rag chews, so it is not a loss, but is a trade off you must consider
depending on your target contact location.
The vertical is generally less efficient - and not just because it does
not have gain - it is worse... IT HAS LOSS. A yagi beam usually has
GAIN. So LOSS goes in one direction... and GAIN goes in the other,
which means it is not a trivial matter.
But there is more to consider...
The useful size of a yagi beam tends to be on the 20M and higher
bands (sometimes also 40 M depending on your budget, your
available real estate, your tower height and surrounding landscape,
etc.) as they can get rather long in the beam and require some
serious space for rotating them. Thus, it is going to matter as
to what bands you wanna work, your budget, and available space.
So... let's say you wanna work 20 M DX... then I vote the tower with
yagi beam if possible - it has gain, and nulls or attenuates the
undesired directions.
But let's say you wanna just work 20 M regional domestic rag chew,
then maybe the vertical works best as it is omni directional, and does
not null out one guy's QTH while focusing on another guy's QTH,
and tends to have take off angles that more favor the local rabble,
then long throw DX.
On the other hand, let's say you wanna work 80 M DX... then a yagi
that size will require some considerable tower dimensions, and
some rather substantial room to rotate. So, maybe that vertical
which has OK radiation pattens for 80 DX and some regional rag
chewing, also might be a better choice. (Recall we are comparing
the vertical to the yagi - and not other types of antennas...)
Then, again, on 40 M, it will depend on the size of your tower, the
angels you wanna work, and so forth. A 40 M yagi is pretty big,
and requires some substantial tower dimensions, but is not altogether
huge... not like that 80 M yagi - those are gigantic and quite unwieldy,
but still the 40 M yagi is a large antenna and requires some big tower
and real estate. That vertical may have some really good 40 M take
off angles, and may even be fairly efficient (compared to, say, how
it works on 160 M, and 80 M, but the yagi, if you can fit it in the yard
and in the budget will still have gain and the vertical will not.
So... the answer is "it depends" on many factors, - and I have only
mentioned a few so far - including your financial resources, your
real estate available, your goals and target bands and contact
locations, the frequencies you want to work, the location (direction)
of your target contacts, and what your wife might allow (and this
latter factors is the MOST IMPORTANT as it carries the most weight
in the decisional matrix.)
Considering my financial resources, and my rather limited real estate
and my desire to work 160, 80, 40, and 20 meters - some DX and
rag chew anywhere in the US... I chose a dumb old vertical - even
though it is not as efficient as a yagi beam. I cannot erect a tower
with a beam for these lower bands, and even a tower with a wire
antenna for those bands will not fit in my back yard and comply
with local tower regs. So I like my vertical - warts and all. (Even
though it is not the best possible antenna, it is a good compromise
for ME in MY LOCATION and under MY circumstances.)
But, MOST GUYS PREFER GAIN OVER LOSS and want to work
OTHER BAND than I do. So my vertical would not be a good
choice FOR THEM under THEIR circumstances. And they pick on
me for this !! But that's OK, because they are trying to help me get
to a better antenna - and that is what friends do for each other.
;-)
I would hang a big 160 M dipole 80 feet up if I had the space, or
even 150 feet of wire at 50 feet... but I do not have the space... so
my vertical suits my needs fine. It worked really swell in the recent
SSB DX Contest on 20 meters - but, if I was a serious contester,
and wanted more rare DX, and wanted to work more on the higher
bands (i.e., 20 M and up), then a yagi beam would beat my vertical
nearly every the time. (Again, we are not comparing either vertical
or yagi to any other type of antenna ....)
Thus, I like my vertical antenna - mainly because it IS A COMPROMISE
that suits my needs - but you gotta weigh the gives and takes carefully.
It is not going to suit everyone. And yes, I am working on plans for
a medium height tower with a yagi beam on it in the near future...
Why? Because no antenna covers all bands well... There are days
when I want that little extra punch the yagi would give me on 20 M.
My vertical does really well as an all purpose Swiss Army Knife
Antenna - HOWEVER - A YAGI HAS GAIN.
So... consider... do you want gain on the higher bands, or to just
get on the lower bands and do OK... can you afford, and do you have
space for a better low band antenna? I do not, so the big vertical is
really good for me,... but if you have a couple hundred feet of space,
and can afford a tower, or have some nice tall trees in the right location,
then stick up a beam for the upper bands, and a lot of wire for all the
bands. Stick up a vertical also, and have it all, if you can.
So.... make a list of your goals... then make a list of your assets and
limitations... and determine whether or not you want that vertical or a
yagi.
Oh... and parenthetically... did I mention the yagi has GAIN ?
Happy trials. ============= Richards - K8JHR =============
John Geiger wrote:
> Also, how would a roof mounted 1/4 wave vertical compare to a 2 element
> tribander at a low height-like 25 feet or so?
>
> _______________________________________________
>
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