Return to KLUBNL.PL main page

[Top] [All Lists]


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
In-reply-to: <[email protected]>
References: <[email protected]> <[email protected]>
Reply-to: [email protected]
Sender: [email protected]
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 ?

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.
----- Original Message -----
From: Graham
Sent: Friday, May 08, 2015 4:54 PM
Subject: LF: UNIPOLE 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  ?
<Prev in Thread] Current Thread [Next in Thread>