[Towertalk] Grounding an Elevated vertical

Tonno Vahk Tonno Vahk" <tonno.vahk@mail.ee
Mon, 11 Mar 2002 11:48:27 +0200


This is a multi-part message in MIME format.

------=_NextPart_000_00DA_01C1C8F2.A888E830
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

As far as nobody really reacted to the statement of yours that passive =
ground screen under elevated radials is a mistake I would like to =
emphasize that it is not. Most of the comments in this thread would also =
lead you to a conclusion that by having a vertical elevated some 10 feet =
off the ground and using a few elevated radials leaves you hardly =
exposed to your ground conductivity.

Thus how can you deny that installing a nearly perfect ground screen =
under elevated vertical with a few radials frees you from 3-4-5-6 or =
whatever DBs of ground loss in the system?

Why not use ground mounted vertical then? Why have all the trouble with =
elevating?

4 Reasons for using 1 elevated radial:
1. You can tune the vertical by simply changing the radial length.
2. You can get some directivity in the desired direction (use 2 or more =
if you don't want that to cancel the currents!!)
3. You get different and better pattern from ground mounted vertical! 10 =
feet elevation on 80m gives you much better pattern especially F/B-wise =
on higher angles! Model if you don't believe!
4. You can get some horizontal radiation using 1 radial and elevating by =
more than 0.05 wl - you might want it for local presence!

I am using full size 80m 4Square elevated 10 feet with 1 elevated radial =
per vertical and a passive ground screen of 64 c.a. 1/4 wl radials per =
vertical on the ground - it's my ideal system! In the air tests have =
given only very good results too.

I tried 4 elevated radials instead of one - did not perform better! =
Rather worse patternwise and modelling confirms that.
I tried to connect the ground screen to the vertical  - no change except =
in the resonance curve as expected!

I had somebody also telling me that a traditional ground mounted system =
would give me much better performance!!!
Better kill that myth right now.

:)
73
Tonno
ES5TV


  ----- Original Message -----=20
  From: K4IA@aol.com=20
  To: K4BEV@aol.com=20
  Cc: towertalk@contesting.com=20
  Sent: Thursday, March 07, 2002 3:42 PM
  Subject: Re: [Towertalk] Grounding an Elevated vertical


  With all due respect to those who have suggested you create a ground =
screen in addition to the elevated radials, I think that is a mistake.

  Your elevated radials are your RF ground and make up the second half =
of the antenna.  If you add another RF ground 10 feet below I think you =
will throw the antenna off without gaining anything.  For one, the 10 =
feet of wire to the earth will act as part of your antenna system.  =
Elevated radials require fewer radial wires and work just fine.  They =
don't need any help.  If you feel compelled to improve your=20
  RF ground add 2 more elevated radials. Cebik seems to think 4-8 =
elevated radials slightly less than 1/4 wavelength long is all you need. =
 Check out his articles at http://www.cebik.com/gp.html and =
http://www.cebik.com/gup27.html

  You do need a lightning ground and that is where your idea makes =
sense.  Run a #4 wire to the ground rod and wrap the antenna end of it =
with electrical tape.  Then tape the taped end to the bottom of your =
vertical.  You could try to create your own spark gap by leaving some of =
the #4 exposed and have it close to, but not touching the vertical.  Run =
your coax down the side of the ground wire and tape it to the ground =
wire for a foot or so before you take a right angle turn to run off to =
the shack.  The theory here is the lightning, looking for the shortest =
and straightest path to ground, will jump across the electrical tape (or =
the gap) and go straight to ground.  Nothing in the amateur realm will =
give complete protection against a direct strike but it may bleed off a =
lot of the hit before it travels back to your house.

  The topic of grounding is a a **hot** one and this post may generate =
some strong comments.  That is good.  I don't think my idea will hurt =
anything and if you want to try attaching the radials to the ground =
wire, you do that to as an experiment.  Let us know how it turns out.

  Radio K4IA
  Craig Buck
  Fredericksburg, Virginia USA
  QRP ARCI #2550  FISTS #6702 CC 788 Diamond #64
  K1 #470    K2 #2460=20
  ----------------------------------------------
  For cheap long distance, 800#s and more

  Tune to http://www.ld.net/?bucksavers
  4.9 cents/min - no monthly fees=20

------=_NextPart_000_00DA_01C1C8F2.A888E830
Content-Type: text/html;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
<META content=3D"MSHTML 6.00.2600.0" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>As far as nobody really&nbsp;reacted to =
the=20
statement&nbsp;of yours that passive ground screen under elevated =
radials is a=20
mistake I would like to&nbsp;emphasize that it is not. Most of the =
comments in=20
this thread&nbsp;would also lead you to a conclusion that by having a =
vertical=20
elevated some 10 feet off the ground and using a few elevated radials =
leaves you=20
hardly exposed to your ground conductivity.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Thus how can you deny that installing a =
nearly=20
perfect ground screen under elevated vertical with a few radials frees =
you from=20
3-4-5-6 or whatever DBs of ground loss in the system?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Why not use ground mounted vertical =
then? Why have=20
all the trouble with elevating?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>4&nbsp;Reasons for using 1 elevated=20
radial:</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>1. You can tune the vertical by simply =
changing the=20
radial length.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>2. You can get some directivity in the =
desired=20
direction (use 2 or more if you don't want that to cancel the=20
currents!!)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>3. You get different and better pattern =
from ground=20
mounted vertical! 10 feet elevation on 80m gives you much better pattern =

especially F/B-wise on higher angles! Model if you don't =
believe!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>4. You can get some horizontal =
radiation using 1=20
radial and elevating by more than 0.05 wl - you might want it for local=20
presence!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>I am using full size 80m 4Square =
elevated 10 feet=20
with 1 elevated radial per vertical and a passive ground screen of 64 =
c.a. 1/4=20
wl radials per vertical on the ground - it's my ideal system! In the air =
tests=20
have given only very good results too.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>I tried 4 elevated radials instead of =
one - did not=20
perform better! Rather worse patternwise and modelling confirms=20
that.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I tried to connect the ground screen to =
the=20
vertical&nbsp; - no change except in the resonance curve as=20
expected!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>I had somebody also telling me that a =
traditional=20
ground mounted system would give me much better =
performance!!!</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Better kill that myth right =
now.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>:)</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>73</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Tonno</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>ES5TV</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
  <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A title=3DK4IA@aol.com href=3D"mailto:K4IA@aol.com">K4IA@aol.com</A> =
</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A title=3DK4BEV@aol.com=20
  href=3D"mailto:K4BEV@aol.com">K4BEV@aol.com</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Cc:</B> <A =
title=3Dtowertalk@contesting.com=20
  href=3D"mailto:towertalk@contesting.com">towertalk@contesting.com</A> =
</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, March 07, 2002 =
3:42=20
  PM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [Towertalk] =
Grounding an=20
  Elevated vertical</DIV>
  <DIV><BR></DIV><FONT face=3Darial,helvetica><FONT size=3D2>With all =
due respect to=20
  those who have suggested you create a ground screen in addition to the =

  elevated radials, I think that is a mistake.<BR><BR>Your elevated =
radials are=20
  your RF ground and make up the second half of the antenna.&nbsp; If =
you add=20
  another RF ground 10 feet below I think you will throw the antenna off =
without=20
  gaining anything.&nbsp; For one, the 10 feet of wire to the earth will =
act as=20
  part of your antenna system.&nbsp; Elevated radials require fewer =
radial wires=20
  and work just fine.&nbsp; They don't need any help.&nbsp; If you feel=20
  compelled to improve your <BR>RF ground add 2 more elevated radials. =
Cebik=20
  seems to think 4-8 elevated radials slightly less than 1/4 wavelength =
long is=20
  all you need.&nbsp; Check out his articles at <A=20
  href=3D"http://www.cebik.com/gp.html">http://www.cebik.com/gp.html</A> =
and <A=20
  =
href=3D"http://www.cebik.com/gup27.html">http://www.cebik.com/gup27.html<=
/A><BR><BR>You=20
  do need a lightning ground and that is where your idea makes =
sense.&nbsp; Run=20
  a #4 wire to the ground rod and wrap the antenna end of it with =
electrical=20
  tape.&nbsp; Then tape the taped end to the bottom of your =
vertical.&nbsp; You=20
  could try to create your own spark gap by leaving some of the #4 =
exposed and=20
  have it close to, but not touching the vertical.&nbsp; Run your coax =
down the=20
  side of the ground wire and tape it to the ground wire for a foot or =
so before=20
  you take a right angle turn to run off to the shack.&nbsp; The theory =
here is=20
  the lightning, looking for the shortest and straightest path to =
ground, will=20
  jump across the electrical tape (or the gap) and go straight to =
ground.&nbsp;=20
  Nothing in the amateur realm will give complete protection against a =
direct=20
  strike but it may bleed off a lot of the hit before it travels back to =
your=20
  house.<BR><BR>The topic of grounding is a a **hot** one and this post =
may=20
  generate some strong comments.&nbsp; That is good.&nbsp; I don't think =
my idea=20
  will hurt anything and if you want to try attaching the radials to the =
ground=20
  wire, you do that to as an experiment.&nbsp; Let us know how it turns=20
  out.<BR><BR>Radio K4IA<BR>Craig Buck<BR>Fredericksburg, Virginia =
USA<BR>QRP=20
  ARCI #2550&nbsp; FISTS #6702 CC 788 Diamond #64<BR>K1 =
#470&nbsp;&nbsp;&nbsp;=20
  K2 #2460 <BR>----------------------------------------------<BR>For =
cheap long=20
  distance, 800#s and more<BR><BR>Tune to <A=20
  =
href=3D"http://www.ld.net/?bucksavers">http://www.ld.net/?bucksavers</A><=
BR>4.9=20
  cents/min - no monthly fees</FONT> </FONT></BLOCKQUOTE></BODY></HTML>

------=_NextPart_000_00DA_01C1C8F2.A888E830--