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Author Topic: Asked and answered many times I'm sure . . . which antenna . . . HF . . vertical  (Read 395 times)

W4PCK

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These are my parameters:
No room for ground radials
No HOA restrictions
Have: 47' Rohn 25 tower
Have: full legal amplifier
Would like to be able to work the community, as well as DX
Have been looking at the wonderful reviews here, and have yet to find (not saying they're not there) something well built, doesn't need five people and reverse engineering to assemble and erect, built to handle the power for the next 9/11.

Ready to purchase, or build.

Just obtained my EXTRA, and have a steep learning curve still.

Located in NoVA.

73

Paul
W4PCK
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W0CKI

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And the amount of money that you have ?
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W4PCK

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I suppose I could squeeze $800 or $900 out of the piggy bank . . .
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N6MST

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No room for radials but a decent height tower?

Mosley TA-33-JR WARC
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K1VSK

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  • Posts: 1947

I suppose I could squeeze $800 or $900 out of the piggy bank . . .
a good sized rotor can cost that much. Add the rotor cable and coax, grounding system and surge protectors and welcome to ham radio budgeting.

As for the antenna, there is no consensus answer and everyone has their favorite (pride of ownership). The bigger, the higher, the better.
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K6BRN

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No room for radials but a decent height tower?  Mosley TA-33-JR WARC

Note that the smaller traps of the Mosley TA-33-JR will NOT handle a full legal limit amplifier, which the O.P. says he has, at full bore.  The TA-33 and TA-33-MW can handle about twice the power but are still limited to 600 Watts on "high duty cycle" modes like FM and FT8.

Within their limits, the Mosley antennas are excellent performers and well built.

Brian - K6BRN
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RR999

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The thread title seems to imply a vertical HF antenna. Probably something with minimal to no horizontal space required. ??

If so, the Cushcraft R8 or R9 comes to mind. Either needs about 8' horizontal space at height for their various radials. 1500w PEP rated, though down to a 500w rating for higher duty cycles. Not exactly my idea of fun to assemble, but it is doable with enough patience. An antenna analyzer, even an inexpensive NanoVNA, would be a huge plus for tuning. Toss together a basic temporary tilt-up mast for initial assembling and tuning before transferring to the tower.

Note the R9, like most multi-band HF verticals, has a such as small sliver of 80m bandwidth that an 80m loaded half-sloper off the tower (if possible) might actually be a better solution. Alternatively, if feeling *really* adventurous, the tower and vertical probably could be shunt fed for 160m/80m.

As for the VHF/UHF bands, a typical dual- or tri-band vertical could be deployed on a tower side arm mount.
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WB6BYU

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Let's consider the various parameters you gave.

First, from the title, you want a vertical.
Any particular reason?  That might, or might not,
be a good choice since you already have a tower.

Any particular bands you want to operate?  That
makes a big difference.

How much space around the antenna do you have
to work with?


Quote from: W4PCK

These are my parameters:

No room for ground radials



No room at all, or "not as far as I'd like"?
What about elevated radials?

For ground-mounted verticals, there are trade-offs.
You certainly can use a quarter wave vertical with
just a ground rod at the base, although often it
won't be as efficient compared to one with a good
set of ground radials.  But that's a trade-off that
you need to make, based on your operating
preferences:  there is no "right" or "wrong" choice.

If you do put a vertical at the top of the tower, it
may still require radials, which would be wires
sloping down at an angle to some sort of tie-off
point (which might be at ground level or elevated).
Do you have room to run those out 60' or so from
the base of the tower?


And that trade-off between performance and other
factors (size, complexity, cost, or whatever) will
continuously crop up in this discussion.

Quote

Have: 47' Rohn 25 tower



Are you assuming the antenna will go on top
of the tower?  If so, does it need to be vertical?
How far can it hang out horizontally from the
top of the tower?

Mounting an HF vertical on top of a tower isn't
always the best approach, especially on the lower
bands where propagation is more via the ionosphere
rather than line-of-sight (like VHF).

But a horizontal dipole, beam, or quad can work well
on top of the tower, especially with a rotator so you
can aim it in the desired direction.

The tower can also be used to support wire antennas,
which may be more practical on the lower bands like
40m or 80m.


Quote

Have: full legal amplifier



That's going to rule out some of the shorter options,
as the traps are prone to overheating (some are only
rated for a few hundred watts).  And the operating
mode becomes important:  many antennas have a
lower power rating for CW, FM, or digital modes than
they do for SSB, because the lower average power
means less heating.


Quote

Would like to be able to work the community, as well as DX



That brings up a number of options...

How far out do you consider your "community"
to extend?  In many cases, more local work these
days uses VHF/UHF, rather than HF.  A ~ 4' to 10'
vertical on top of the tower should work well,
although your coverage area will depend on your
local topography and what repeaters you have
available.  That's what I would plan to use for
distances up to 10-20 miles on simplex, or out
to 40-50 miles (and in some cases much further)
using repeaters.

For distances out so several hundred miles,
NVIS (high-angle) propagation on 40m through
160m is likely to give the best coverage.  The
choice of bands will depend on the current
ionospheric conditions, and  you likely will need
to change bands to maintain 24 hour coverage.

Now, a vertical antenna is a relatively poor choice
for this coverage, as it tends to have a null overhead,
which is where you want maximum radiation.  A
wire dipole, even at a relatively low height, will
generally work better (besides being much simpler
and cheaper, and not needing ground radials).
You might need several of them connected to the
same feedpoint to cover multiple bands.

Ionospheric propagation on the higher bands will
generally have minimum distance of 500 miles or
more, unless stations are relatively close (but there
may be exceptions).



So, yes, there are vertical antennas that claim multi-band
operation with no ground radials, but they are often
limited in their power handling.  (Some versions are
intentionally lossy to improve the SWR, but that means
that they are dissipating much of your power as heat
rather than radiated RF.)  And, in order to cover (or at
least claim to cover) all HF bands in one antenna with
useful radiation patterns can require a fair bit of complexity,
or large physical size.

Part of the problem also is that the same antenna
polarization or other characteristics may not be optimum
for all the HF bands.


A common solution would be to choose a combination of
antennas, rather than just one.  A common approach is to
use a rotatable beam antenna for 20m through 10m (with
or without 17m and 12m, depending on your preferences).
Or you might find that just a 20m antenna is sufficient for
working longer distances most of the time - again, that is
a personal decision, but there are many options in that
category.  Then 40m and 80m (and possibly 160m, 60m,
and/or 30m if desired) would use inverted vee dipoles
using the tower as a center support.  That gives you both
the local coverage on the lower bands (although not just
limited - could cover a couple thousand miles or more),
and DX / longer distances on the higher ones.  For local
work, you can stick a VHF/UHF FM antenna on top of the
tower as well.

That's a common and simple solution with good all-band
coverage.  But, other than the VHF/UHF antenna, none
of them are verticals.  That's why it is important to
understand the reason for that specification.


If you want to stick with a vertical, then something like
the DX COMMANDER, or a home-buit version, might be
a reasonable choice.  This is really just a bunch of
quarter wave wires for each band of interest running up
to a pair of cross-arms, with coax attached at the
base.  Because there are no traps or loading coils
(although you might need to add a coil for 80m),
there isn't much to limit the power handling capacity.
Yes, you would have better performance with a better
ground system, but if all you can manage is a ground
rod or two at the base of the tower that you use to
support the wires, that maybe adequate for your
needs.  There are other variants on that same approach,
depending on what bands you want to include.


So one reason that  you don't find a lot of antennas that
met your original criteria is that making a single vertical
that covers all the HF bands with a useful radiation pattern
is pretty complex.  I have one up in the attic that is rated
to cover 40m through 10m (a Cushcraft R7 I think) and,
while, yes, I can set it up by myself, it can be rather
complex to adjust, easy to detune if there is anything
near the feedpoint, has narrow operating bandwidth,
and...   well, the fact that it is in a bucket up in the attic,
rather than set up and in use, may give you an idea of
how well I like using it.

In another case, a multiband vertical claimed to "work"
on 80m was measured to be 1% efficient.  That means,
with 1 kW input, you'd get about 10 watts radiated.  But
only briefly:  the remaining 990 watts turned into heat
would quickly melt the antenna.


But, if you still want one antenna with good performance
over all or most of the HF range, there are some options.

Like this, or this, or this, or this.

But they might not be in your price range.

W4PCK

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WOW, I’m impressed, and smarter now.  THANK YOU!!!

And I’m no longer wanting that imagined vertical, for the reasons given.

What started all this, and you may find this silly, was my OCF antenna performance was crap on 10m, so much so, I could not participate in the local club’s 10m net.

As suggested, I do have a vertical for VHF/UHF on a side mount from the tower, and that works just fine for reaching local repeaters and participating in that net.

The so-called “Windom” OCF is strung between the tower, over and inline with the the peak of the roof, and attached to a Dawn Redwood I planted shortly after moving in in the late 90’s.  I have that end connected with UV-resistant cord run through a pulley and down to a counter weight, to allow for the tree movement in the wind.

Have more homework to do here.

My thought with the vertical was the idea that the vertical polarization would be better able to be received locally - that’s all.

Thank you.
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WB6BYU

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  • Posts: 20894
    • Practical Antennas

Quote from: W4PCK

...What started all this, and you may find this silly, was my OCF antenna performance was crap on 10m, so much so, I could not participate in the local club’s 10m net.

...

My thought with the vertical was the idea that the vertical polarization would be better able to be received locally - that’s all.




Well, it might be, depending on the antenna
polarization used by the other net participants.

That’s a good place to start doing your homework!

If they are mostly vertical (perhaps using old CB
antennas) then that may be the best choice, at
least for that net on 10m.

The OCFD, assuming it covers down to 40m, or
especially 80m, is going to be mostly horizontally
polarized, and will have various lobes and nulls
in the pattern, that could give good coverage in
some directions but not in others.  And likely the
primary propagation mode is direct wave, like
on VHF, so height (and matching polarization)
is more important.

But also the range is going to be rather limited,
so if you are just a bit further out than many of
the stations, you may have a poor signal even
with the right polarization.

So there are several possible reasons why your
having problems checking into the local 10m
net, some of which may be independent of your
choice of antenna.

So my first suggestion is to contact the club
and / or the net control station and find out
what polarization they use, and what their
expected coverage area is.  From that, we
can see if a different antenna would help.

Depending on the circumstances, you might
need a specific antenna just for checking
into the net, although it wouldn’t surprise
me if many of the stations are using horizontally
polarized beams.  It might be that your
current antenna would work better pointed
in a different direction (maximum radiation
will NOT be broadside to the wire on 10m),
and a simple wire dipole or loop might work
better if the OCFD can’t be changed.


So consider this a starting point in the
(sometimes seemingly endless) discussion
about choosing antennas.

W6HB

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  • Posts: 50

Consider a hexagonal beam and a used rotator....
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US7IGN

  • Posts: 75
    • https://www.us7ign.com/

Any homemade yagi on 14MHz and up. I made SpaderBeam https://www.us7ign.com/?p=84 and OB-16-3 http://www.us7ign.com/?p=166
Inv.V or 4SQ https://www.us7ign.com/?p=372 on 30, 40 and 80 meters
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RR999

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https://w6af.com/makerspace/build-your-own-ham-antennas/10-meter-vertical-to-cover-a-30-mile-radius-net/

As WB6BYU noted, there are decent odds many on your local 10m net could be using repurposed end-fed 11m CB verticals or popular multi-band amateur verticals, especially if using FM. Ask the participants, and if so, you are likely going to want a vertically polarized antenna as well due to cross polarization losses with your existing horizontal OCFD.... assuming you are truly that interested in regularly participating in the net.

Most of the 11m/10m "base" antennas are a typical end-fed 1/2w or 5/8w vertical using a matching network at the feedpoint. The matching network is a critical component, especially with many CB verticals claiming 2KW PEP or higher power ratings, but do you like rolling the dice? Some of the amateur-marketed models seem a little more realistic with their ratings. Either way a few to several hundred watts in a low duty cycle mode like SSB might be okay depending upon the particular antenna (check user reviews!), along with usually more than sufficing for a local 10m net. Seriously derate the power limits for FM and other high duty cycle modes. Also forget the optional elevated "radial kits" and spend the difference to add a decent common-mode choke on the feedline. IMO, YMMV, and at that of course. ;)

https://www.hfkits.com/common-mode-chokes/
http://www.karinya.net/g3txq/chokes/

A 10m end-fed 1/2w or 5/8w vertical can be homebrewed, though if you do not mind elevated radials, an even more basic quarter-wave ground plane does not require a matching network.

BTW, beyond local comms, 100w and even down to QRP into a decent vertical with a low radiation angle often can work tremendous distances when 10m propagation cooperates.
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K5LXP

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The data point I'll offer is "tools in the toolbox".  There's no one size fits all antenna.  The answer to your question won't be just a vertical, just a beam, just a dipole, just a [blank].  Remove 'just' and put in 'and' - a dipole, and a beam, and a vertical, and a [blank].  None of these have to be complicated or expensive.  Wire is cheap, small beams go up fairly easily, verticals you can plant most anywhere.  Then when operating pick the best tool from your toolbox for the band/conditions you need.  Maybe you can't run the amp with some of them.  So what - that will net you more contacts than you would with no antenna.  Start with something, anything, and add on/change from there. 

Mark K5LXP
Albuquerque, NM
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K1KIM

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The thread title seems to imply a vertical HF antenna. Probably something with minimal to no horizontal space required. ??

If so, the Cushcraft R8 or R9 comes to mind. Either needs about 8' horizontal space at height for their various radials. 1500w PEP rated, though down to a 500w rating for higher duty cycles. Not exactly my idea of fun to assemble, but it is doable with enough patience. An antenna analyzer, even an inexpensive NanoVNA, would be a huge plus for tuning. Toss together a basic temporary tilt-up mast for initial assembling and tuning before transferring to the tower.

Note the R9, like most multi-band HF verticals, has a such as small sliver of 80m bandwidth that an 80m loaded half-sloper off the tower (if possible) might actually be a better solution. Alternatively, if feeling *really* adventurous, the tower and vertical probably could be shunt fed for 160m/80m.

As for the VHF/UHF bands, a typical dual- or tri-band vertical could be deployed on a tower side arm mount.

I have a Hustler 5-BTV that is practically worthless on 80M except for the very narrow bandwidth you've  cut the whip to. This has prompted me to build an EFHW to cover the entire 80M band. Since I have dedicated doublets for 17M and 10M and a 6M Squalo I've tuned the EFHW to 80M at the expense of the other bands. The trapped vertical covers my needs on 20M and 40M.

As stated, a vertical atop the tower will be your least expensive option, but still pushing your budget. At the proposed dollars, a Yagi etc with a rotor for legal limit is out of the question.
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So Many Toys.......So Little Time!
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