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Re: LF: Re: UNIPOLE V INV-L ?

To: <[email protected]>
Subject: Re: LF: Re: UNIPOLE V INV-L ?
From: "Graham" <[email protected]>
Date: Fri, 8 May 2015 19:48:17 +0100
Importance: Normal
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Ok Alan,  ..laws
 
That's  easy  , just claim there linked to  dark  matter , then  anything  go's   : ) 
 
A ground  mounted  ui-pole , is it  really  just  a  short    thin loop  ? , if the   ATU  earth  is  bonded to  the  ground  point  ? , IF..the  current   at the   earth  and  at   the  feed point  are  equal  and  opposite , then  nothing  will  happen , or  have  I missed  something  ?   or is  there  a  diminishing  distribution  , but  over a  short loop  , what  go's  out , must  come  back to  the  tuner  ?   what's  radiating  or is it establishing  a  near  field   by cancelation , ala counter-would   ? .. Its  something that  could be  erected  in the   uk 20x40   back   plot..
 
This  talks  of  top loading  and   'ground reference system '  what  ever that  is , no  info  , unless  its a  tuned  counterpoise  .... something  I had not  though of ,   tuner  in the  earth line  to  match  to the  ground  z   on 477 ....   what  happens  at commercial   mw  sites , marine  wise  the  hull  is earth  ?
 
 appears  to  have  a  cage of  wires  to  increase  the  tower diameter ,  the  tower  is actually  broken  up  with  insulators  , once again ,  may be the  effort  should be  in establishing  a  top loaded  vertical  cage / top ,loading    and  not  a  multi  wire  top ?
 
 
bbc  mw  tx  side 
 
 
nav text  mf  Ae 
 
 
 
Ranges  on the   radiation  plot  look  familiar   250/300 K first  skip ?
 
73-G,
 

From: Alan Melia
Sent: Friday, May 08, 2015 5:28 PM
Subject: LF: Re: UNIPOLE V INV-L ?

Hi G,
Well the Laws of Physics dont change however much one might wish it :-))
 
The unipole will be approx -3dB ERP on the inv L
 
Effective height of unipole approx half physical height
Effective height of inv L same height with 1.5*h top is approx 0.9* physical height
 
inv L disadvantage.....requires another support and insulators
inv L advantage ........over poor ground with the same feed-point grounding the inL will have lower ground loss and higher capacity. Over good ground or sea-water this advantage may disappear, but losses will be low anyway.
 
I think this folded monopole is covered in Rik's tutorial, the extra wires are just "matching" they dont increase the radiation resistance. Commercial stations like grounded aerials for lightning protection.
 
Alan
G3NYK 
----- Original Message -----
From: Graham
Sent: Friday, May 08, 2015 4:54 PM
Subject: LF: UNIPOLE V INV-L ?

UNI-POLE  V  INV-L ?
 
 
Assuming  a robust   ATU and   earth   
 
What would be the  advantage  / disadvantage   of  say  a   40  foot  uni-pole  ,   to  a  conventional     40 x 60   ft  inv L   at  MF ?
 
tower  and  side wire  or   RG8U  / copper  pipe  construction ? .........  -3 dB  of a  similar size loop  ?
 
73-Graham
G0NBD
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