Question about vertical and radial placement

[djmd]

Hello,

Currently without any HF antenna and after seeing my friend's success with
his homebuilt vertical, I'm starting to consider a self-supported 43'
allbander, from DX-Engineering or the like. Not really looking to discuss
general performance vs. other antennas, but I am curious about my options
for installing.

I live in a very standard subdivision-type lot, about 180'x70' with a
single-story 55'x25' house right in the middle. The one option that I have
to rule out is putting the antenna smack-dab in the center of the backyard.
Besides just not wanting an antenna in the middle of my backyard, that would
put the antenna way too close to the 7200v powerline strung over my property
line. About the only ground-mounted option would be 5-10' away away from the
back of the house, which would make it clear the high-power line, but it
could still come in contact with my 240v residental feed if it went over in
that direction.

My ideal location would be on the roof. Not only could I be 100% clear of
any powerlines, phone, or cable, but it would be nearly 20' higher, and
basically in the clear of anything to the sides. My question, therefore, is
what about radials? Draping radials across the roof doesn't sound like an
option to me, mainly for asthetic reasons. So I ask: could I send #2 or #4
copper from the antenna base to both the front and the backyard, and connect
it each one to radials in both the front and back yard? I would be mounting
this antenna within 10' of the end of the house, so I could send 1 piece of
copper down one of the ends of the house, and then split off from there in
each direction. It would probably then take about another 20-30' in each
direction before it met with the radial distribution point.

Thank you for any insight. Will probably post this to eham verbatim as well,
but wanted to start here.

K8DJW




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[Mike WA8BXN]

With a wire running down to the radials, you would have something more like
an off center fed vertical dipole. The distance to ground would be near a
quarter wave for some bands. Heavy wire would not change that. Have you
considered going through the roof with a wire to a counterpoise in the
attic?

73 - Mike WA8BXN

 
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[Phil Kane-2]

On 2/14/2010 4:17 PM, djmd wrote:

> Currently without any HF antenna and after seeing my friend's
> success with his homebuilt vertical, I'm starting to consider a
> self-supported 43' allbander, from DX-Engineering or the like.
> Not really looking to discuss general performance vs. other
> antennas, but I am curious about my options for installing.

          [balance snipped]

  My lot is about the same size as yours.

  Consider the Cushcraft R-8 (or R-9 if they have brought it out)
  which is what I use with my K2.  It does not require an external
  "radial field" because it has its own decoupling skirt - hard
  to describe but easy to see in a photo or drawing of it.

  I installed it off the back deck of my two-story house on a 10
  foot mast so that the decoupling skirt clears the 8 foot high
  deck structure.  Another 10 foot piece of conduit is installed
  over a ground rod (safety/lightning ground, not RF ground) and
  the top of that conduit is bonded to the bottom of the mounting
  mast as well as the bottom of the conduit bonded to the round
  rod.

  Works like a charm!

--  73 de K2ASP - Phil Kane
    Elecraft K2/100   s/n 5402

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[Don Wilhelm-4]

You are likely to get a lot of ideas and comments, but a bit of study
will substantiate what I am about to say on the subject - it is all just
practical physics, no real 'magic' involved.  (OK -- some theory from EE
Field Mechanics theory is involved too).

If you mount the 43 ft. vertical on the roof and run a heavy gauge wire
from the roof to the ground, the length of the vertical will be
increased by the length of the wire.  I don't know whether that is good
or bad - it all depends.  For low band use, the extra length can be a
good thing, but the take-off angle on the higher bands will not be as
expected (and published) for a 43 ft. radiator - it will begin to break
up into higher angled lobes.  At what frequency that occurs depends on
th length of the added wire.

If what you want is the 43 foot vertical, then buy enough telescoping
tubing (DX Engineering is one source) to make the total of your "wire
from the housetop" plus the vertical radiator equal to 43 feet (not
critical since it must be tuned anyway).  Then you can bury the radials
in the yard.  How efficient it will be depends on the number of radials.

The other approach is to put the 43 foot vertical on the rooftop and use
4 43 foot radials at its base (yes, 4 wires on the rooftop) - they can
droop down the corners of the house if there is no other choice - use
insulators as if the radials were antenna wires (they actually are).  
These radials should NOT be connected to ground, but are a part of the
antenna.  You can feed the antenna (and radials) with open wire or
ladder line and use a tuner in the shack.  You should have good
performance on 40 through 10 meters with a low angle of radiation (good
for DX).  The horizontal component of radiation will cancel if the
radial pairs are oriented symmetrically (180 degrees apart).  In fact,
you might be able to get away with two radials rather than 4, but 4 will
be slightly better.  Again, these are elevated radials and are a part of
the antenna system - do not connect them to an earth ground.  You should
achieve a low angle of radiation on 80 through 20 meters, but the lobes
of maximum radiation will be higher above 20 meters.  That is
characteristic of the popular 43 foot vertical.

73,
Don W3FPR

djmd wrote:

> Hello,
>
> Currently without any HF antenna and after seeing my friend's success with
> his homebuilt vertical, I'm starting to consider a self-supported 43'
> allbander, from DX-Engineering or the like. Not really looking to discuss
> general performance vs. other antennas, but I am curious about my options
> for installing.
>
> I live in a very standard subdivision-type lot, about 180'x70' with a
> single-story 55'x25' house right in the middle. The one option that I have
> to rule out is putting the antenna smack-dab in the center of the backyard.
> Besides just not wanting an antenna in the middle of my backyard, that would
> put the antenna way too close to the 7200v powerline strung over my property
> line. About the only ground-mounted option would be 5-10' away away from the
> back of the house, which would make it clear the high-power line, but it
> could still come in contact with my 240v residental feed if it went over in
> that direction.
>
> My ideal location would be on the roof. Not only could I be 100% clear of
> any powerlines, phone, or cable, but it would be nearly 20' higher, and
> basically in the clear of anything to the sides. My question, therefore, is
> what about radials? Draping radials across the roof doesn't sound like an
> option to me, mainly for asthetic reasons. So I ask: could I send #2 or #4
> copper from the antenna base to both the front and the backyard, and connect
> it each one to radials in both the front and back yard? I would be mounting
> this antenna within 10' of the end of the house, so I could send 1 piece of
> copper down one of the ends of the house, and then split off from there in
> each direction. It would probably then take about another 20-30' in each
> direction before it met with the radial distribution point.
>
> Thank you for any insight. Will probably post this to eham verbatim as well,
> but wanted to start here.
>
> K8DJW
>  
>

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[Leigh L. Klotz Jr WA5ZNU]

Contrary to expectations, your radials need not go anywhere near the ground. If your antenna is on the roof then your radials should start at the feed point and remain horizontal, and stay on the roof.  They don't need to go down to the ground and so they won't be visible (at least not compared to a 44ft vertical!). So you might be able to solve your aesthetics problems and get good antenna performance with "elevated radials."  Two per band would be a minimum, and more would be better, but you don't need 160 of them!  There's a good article in QST this month on ground radials and elevated radials and what works best, based on actual tests.  But first, you might want to read a bit on the issue of ground and vertical antennas; getting the wires to the earth isn't important.  (Though you do need some sort of lightning protection which would likely involve that, perhaps by running your coax down to the ground and putting a lightning device there.)

Leigh/WA5ZNU

[Julius Fazekas n2wn]

Buy, beg, borrow or ste.... ummm locate a copy of Les Moxon's, G6XN (SK), book "HF Antennas
for All Locations". He provides some options that are worth considering. The book covers a lot of possibilities for "small gardens", typical in the UK and US.

Don't buy into the 43' vertical hype. It's a good compromise antenna with limitations, particularly on 160/80/75 where top loading would be a much better option.

For the money, a Hustler 5 BTV Antenna, 80-75/40/20/15/10M, HUS-5BTV, also available from DXE is a good buy. If you find out you don't like the way the vertical works, you haven't just dumped $800.

The other nice thing about the Hustler, is it makes a good platform to "build your own" on, down the road.

73,
Julius
n2wn

[N5GE]

On Sun, 14 Feb 2010 16:17:50 -0800 (PST), djmd <[hidden email]> wrote:

See comments in line...


>I live in a very standard subdivision-type lot, about 180'x70' with a
>single-story 55'x25' house right in the middle. The one option that I have
>to rule out is putting the antenna smack-dab in the center of the backyard.
>Besides just not wanting an antenna in the middle of my backyard, that would
>put the antenna way too close to the 7200v powerline strung over my property
>line. About the only ground-mounted option would be 5-10' away away from the
>back of the house, which would make it clear the high-power line, but it
>could still come in contact with my 240v residental feed if it went over in
>that direction.
 
As Julius say's, don't fall for the 43 foot vertical hype.  It would
be better to get a short loaded 5 or 8 band vertical and install a
ground system for it (more about that below).  Most of the loaded
verticals on the market are short enough to be clear of both of your
power lines if they fell.

Loaded verticals do not require a tuner if you adjust them for your
favorite part of each of the bands, so you would save the money you
would have to spend on a tuner.

>My ideal location would be on the roof. Not only could I be 100% clear of
>any powerlines, phone, or cable, but it would be nearly 20' higher, and
>basically in the clear of anything to the sides. My question, therefore, is
>what about radials? Draping radials across the roof doesn't sound like an
>option to me, mainly for asthetic reasons. So I ask: could I send #2 or #4
>copper from the antenna base to both the front and the backyard, and connect
>it each one to radials in both the front and back yard? I would be mounting
>this antenna within 10' of the end of the house, so I could send 1 piece of
>copper down one of the ends of the house, and then split off from there in
>each direction. It would probably then take about another 20-30' in each
>direction before it met with the radial distribution point.

I agree that your ideal location would be on the roof, but you don.
need to have the radials at ground level.  As others have said that
would actually harm the performance of the vertical.

You could mount the vertical on a short mast three feet in length,
then use good stronger copper wire or galvanized steel electric fence
wire for the radials, attaching them to the roof, making sure you use
insulators on the ends of the radials, which are also your guy wires
for the mast.  Then use 3/6 inch UV resistant rope to guy the antenna
itself at three or four points on the roof.  You can use the same
attachment points you used for the radials.

Another method of installing the vertical is to mount it on an eight
foot pipe or wooden 4 x 4 post using the radials to guy the post or
pipe (I prefer the post).  It is best that the radials are parallel to
the ground.

Either installation will result in the installation of a ground plane
antenna.  Do a search on the Internet for "ground plane antenna" and
see if anything you find resemble a solution for your antenna needs.

Also consider a single mast with inverted vee's all fed at the same
feed point, which in most instances will out perform a loaded vertical
antenna and cost about 20 dollars to build.  Building antennas is much
less expensive than buying them ;o)
   
[snip]
>K8DJW

Tom, N5GE

[hidden email]
K3 #806 with SUB RX, K3 #1055, PR6,
XV144, XV432, KRC2,
W1, 2 W2's and other small kits

1 K144XV on order

http://www.n5ge.com
http://www.swotrc.net

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[Don - K2PMC]

As several others have mentioned, I think you would be better served by a multiband vertical such as a Butterrnut, Hustler, HyGain, etc.  As for the radials, elevated radials are clearly superior to ground radials, as demonstrated in the March QST.  I also speak from personal experience as I have modeled elevated radials against ground radials. In my models, 2  1/4 elevated  radials were more efficient than 16  1/4 wave radials on the ground.  I also use 2 elevated radials on my 160 meter T antenna with very good results.  

You should use 2 resonant 1/4 wave radials per band of operation.  The radials should be laid out opposite each other.  As for the appearance, you can use #20 wire which will be invisible from ground level.  Your vertical will perform very well with that counterpoise system.

Good luck,
Don
K2PMC

[Hardy Landskov]

I agree with the reply and results that Don got but we are straying off
course. Please can everyone who is involved take this thread to Tower Talk?
I am still try to learn this radio.
73 N7RT

----- Original Message -----
From: "Don - K2PMC" <[hidden email]>
To: <[hidden email]>
Sent: Monday, February 15, 2010 6:19 PM
Subject: Re: [Elecraft] Question about vertical and radial placement

>
> As several others have mentioned, I think you would be better served by a
> multiband vertical such as a Butterrnut, Hustler, HyGain, etc.  As for the
> radials, elevated radials are clearly superior to ground radials, as
> demonstrated in the March QST.  I also speak from personal experience as I
> have modeled elevated radials against ground radials. In my models, 2  1/4
> elevated  radials were more efficient than 16  1/4 wave radials on the
> ground.  I also use 2 elevated radials on my 160 meter T antenna with very
> good results.
>
> You should use 2 resonant 1/4 wave radials per band of operation.  The
> radials should be laid out opposite each other.  As for the appearance,
> you
> can use #20 wire which will be invisible from ground level.  Your vertical
> will perform very well with that counterpoise system.
>
> Good luck,
> Don
> K2PMC
>
>
> --
> View this message in context:
> http://n2.nabble.com/Question-about-vertical-and-radial-placement-tp4572326p4578117.html
> Sent from the [HAM] mailing list archive at Nabble.com.
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