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Re: LF: Re: InV L Top wire config - Best Option ??

To: <[email protected]>
Subject: Re: LF: Re: InV L Top wire config - Best Option ??
From: "Graham" <[email protected]>
Date: Thu, 21 Jun 2012 21:59:27 +0100
Importance: Normal
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R Alan,
 
Down to   one of  Mr  Hobson's   fine  designs  here ,   the  under slung   wire  , would  be the  simplest to  arrange ,   say  it  ran  10  ft  above  a  90  ft  elevated  ground  radial  , now would  that  xtra  C  , increase the  amp's  in the  vertical  section  , the  other  side  of the  top  coil ...?
 
Other  wise  its ,just possible  to  run  90 deg  about   20 feet  , 90  then  down , at the  far  end 
 
I tune using  a  swr meter  , usually  get a  sharp  dip  with the  variometer  , but  I  also  have a  old   1000  pf   4 gang clipped  , low over the  auto  transformer , that  is handy , just  takes  the  final 'ref   down  and  as its  low , there  is  no  flash  over , bit  like a  band-spread on a  rx oscillator  coil
 
Testing  wise , luckily  , I can  reach the  Delft web-sdr   in the  day  time  , so  can  do  s/n  checks  at  range using  ROS-MF-2    , the  s/n  is the  average  along  the  time  line , so  quite  accurate 
 
Still  raining 
 
73 -G..

From: Alan Melia
Sent: Thursday, June 21, 2012 8:59 PM
Subject: Re: LF: Re: InV L Top wire config - Best Option ??

Hi Graham its not exactlyaerial weather here either :-((
The problem with unconventional "shapes" is you will have to just try 'em out. I have always concentrated on reducing ground loss as the most effective use of time and effort. Best done by measurement, and not urban myths :-))  Thats why I always plug a simple transformer coupled bridge, oscillator and receiver as a detector, noise bridges have never worked at LF for me ....probably too many BC stations close by. I also like bridge measurements......its probably an "age thing" :-))  I feel closer to the problem and able to employ some skill and maybe dexterity, even if I dont get the numbers on the readout of a VNA......at least I learnt to sense when the measurement "feels" right. It is the classic substitution measurement with passive references.
 
Alan
G3NYK
 
----- Original Message -----
From: Graham
Sent: Thursday, June 21, 2012 6:48 PM
Subject: Re: LF: Re: InV L Top wire config - Best Option ??

R Alan.
 
Horizontal  spread  ......missing  at the  moment ...  will  have  another  look  out  side  , when the  rain  stops ,  horizontal   open  box may  be  possible ..just
 
Tnx -G..

From: Alan Melia
Sent: Thursday, June 21, 2012 4:42 PM
Subject: LF: Re: InV L Top wire config - Best Option ??

Hi Graham it basically doesnt matter too much  :-))
The thing is to get as much wire as high as possible. Yes fold it back, meander it....spacings less than about 2 feet dont add much over a single wire. Drop the end if you have to but remember this may reduce the signal slightly in that direction....but it will increase slightly the capacity to ground. be careful of the dropped ends they are high voltage points and may not be "family friendly" ...... doubling the capacity to ground ( note ground....not lossy roofs/foliage underneath) will probably halve you ground losses. It will do very little to increase the radiation resistance.
 
Your diagram is difficult to read but running one of the wires directly under another will be of no benefit and may be worse than not having it......horizonltal spread is what you want, so pull it at least 2 feet aside before folding it back.......I think you get the idea.
 
Alan
G3NYK
 
----- Original Message -----
From: Graham
Sent: Thursday, June 21, 2012 4:17 PM
Subject: LF: InV L Top wire config - Best Option ??

InV  L  Top  wire  config  - Best Option ??
 
Any  thoughts on the  best  configuration  for the  top  wire ??
 
Tnx -G,
 
 
 
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