Tim [WB8UHZ],

How Many : Inverted "L" Antenna Radials for a Receiving Only Antenna ?

http://groups.yahoo.com/group/Shortw...a/message/6572


Most Receive 'only' Inverted "L" Antenna (Random Wire) designs
(drawings)
usually do not indicate any Ground Radials.
[ Side View ] "NONE"

......00|-------------------------00......
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Radio ==============$
GR


Reversing the Lay-Out of the Inverted "L" Antenna allows
the Coax Cable to be placed on/in the Ground under the
Horizontal Antenna Element and have it act as a single
Ground Radial.
[ Side View ] "ONE"

.....00|----------------------00.........x
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$============================= Radio
GR


IIRC - There is one Inverted "L" Antenna design (drawing)
with Two Ground Radials at the Base of the Up-Leg of the
Inverted "L" Antenna with the Radials Perpendicular to
the Horizontal Out Arm when viewed from the Top.
[ Top Down View ] "TWO"

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GRX$-------------------------00........
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Drawing Symbols :
"GR" = Ground Rod
"$" = Matching Transformer
"X" = Connection
"00" = Insulator
"|" or "-" = Wire Antenna Element
"=" = Coax Cable
"." = Rigging Rope


something to think about - iane ~ RHF
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= = = In ,
http://groups.yahoo.com/group/Shortw...a/message/6509
= = = amfone@s... wrote:

Yodar
You can get away with one radial on the bottom , that is it will work ,
there will be losses at the connection, adding two more will help,
there still will be losses but in reality to work "perfect" you would
need to lay about a 150 radials. Fortunatly for good performance this
is not necessary. What your doing by adding the radials is limiting the
ground losses and lowering the take off angel of the antenna , which is
what the inverted L will do for you, its is meant to look at a very low
angel of radiation, hence an excellent DX antenna but not much good for
close in stations. You can use any form of good conduction metal , but
to be most effective the concept is to stretch it out at least a quater
wave length from the (L) portion feed point. I would use for both the
(L) portion and the radials number 14 copper stranded wire insulated. I
think you can get a spool of 500 feet at Home Depot for about $20.00

Tim
WB8UHZ

----- Original Message -----
From: Joe Strain
To:
Sent: Sunday, November 13, 2005 4:43 PM
Subject: [Shortwave-SWL-Antenna] Inverted-L antenna resource


In two, er, three sentences Tim took all the physics
out of it, made the operation dynamics of the antenna
understandable even by this dufus! Thanks sir !

Now, how FEW radials can I get away with if I dont
transmit with the antenna? Can I get away with buried
1/2" mesh "hardware cloth'?

Yodar

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On 18 Nov 2005 04:36:17 -0800, "RHF"
wrote:

mercy killing

Except for a 1/4 wave vertical, why would one need ground radials?

On Fri, 18 Nov 2005 14:58:53 GMT, David wrote:

On Fri, 18 Nov 2005 14:24:38 GMT, Bob Miller
wrote:

On 18 Nov 2005 04:36:17 -0800, "RHF"
wrote:

...excerpted...

I have a little inverted L for 20 meters. A single elevated, 1/4
wave, tuned radial makes all the difference when transmitting.
Eliminates key clicks. Brings down the SWR. Makes little difference
on receive, tho'.

bob
k5qwg


That's a ''counterpoise'' isn't it? ''Radials'' implies more than
one.

http://www.arising.com.au/people/Hol...ph/counter.htm

Yep, one wire is usually called a counterpoise.

bob
k5qwg

Except for a 1/4 wave vertical, why would one need ground radials?

For receive, you really don't need any to "work". But like one said,
adding more will lower the overall angle of radiation and would improve
it for low angle long haul stuff. But how much vs the price of wire
would depend. For receive only , I doubt I would use too many radials.
The payoff is not really worth it, if you don't intend to transmit. Of
course,
if time, $$$$, etc, no object, many radials are better than just a few.
So for some of the harder core, it might be worth the trouble.
MK

BM & David,

Using the Coax Cable as a Counterpoise under the
Inverted "L" Antenna as shown.
{ Counterpoise = A Single Ground Reflector / Radial }

Reversing the Lay-Out of the Inverted "L" Antenna allows
the Coax Cable to be placed on/in the Ground under the
Horizontal Antenna Element and have it act as a single
Ground Radial.
[ Side View ]

.....00|----------------------00.........x
|
|
|
|
|
$============================= Radio
GR

iane ~ RHF